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  • Question 1 - Which segment of the ECG waveform corresponds to the shutting of the mitral...

    Correct

    • Which segment of the ECG waveform corresponds to the shutting of the mitral valve?

      Your Answer: QRS complex

      Explanation:

      A diagram depicting the various stages of the cardiac cycle can be accessed through the external link provided.

      Heart sounds are the sounds produced by the heart during its normal functioning. The first heart sound (S1) is caused by the closure of the mitral and tricuspid valves, while the second heart sound (S2) is due to the closure of the aortic and pulmonary valves. The intensity of these sounds can vary depending on the condition of the valves and the heart. The third heart sound (S3) is caused by the diastolic filling of the ventricle and is considered normal in young individuals. However, it may indicate left ventricular failure, constrictive pericarditis, or mitral regurgitation in older individuals. The fourth heart sound (S4) may be heard in conditions such as aortic stenosis, HOCM, and hypertension, and is caused by atrial contraction against a stiff ventricle. The different valves can be best heard at specific sites on the chest wall, such as the left second intercostal space for the pulmonary valve and the right second intercostal space for the aortic valve.

    • This question is part of the following fields:

      • Cardiovascular System
      17.9
      Seconds
  • Question 2 - A 50-year-old man comes to the clinic complaining of a painful left foot...

    Correct

    • A 50-year-old man comes to the clinic complaining of a painful left foot that he woke up with. Initially, he didn't want to bother the doctor, but now he's concerned because he can't feel his foot or move his toes. Upon examination, the left foot is cold to the touch and very pale. What is the probable diagnosis?

      Your Answer: Acute limb ischaemia

      Explanation:

      Acute Limb Ischaemia and Compartment Syndrome

      Acute limb ischaemia is a condition that is characterized by six Ps: pain, pallor, pulselessness, perishingly cold, paresthesia, and paralysis. It is a medical emergency that requires immediate attention from a vascular surgeon. Delaying treatment for even a few hours can lead to amputation or death. On the other hand, acute compartment syndrome occurs when the pressure within a closed muscle compartment exceeds the perfusion pressure, resulting in muscle and nerve ischaemia. This condition usually follows a traumatic event, such as a fracture. However, in some cases, there may be no history of trauma.

    • This question is part of the following fields:

      • Cardiovascular System
      20
      Seconds
  • Question 3 - Which nerve is most vulnerable to damage when there is a cut on...

    Incorrect

    • Which nerve is most vulnerable to damage when there is a cut on the upper lateral margin of the popliteal fossa in older adults?

      Your Answer: Sural nerve

      Correct Answer: Common peroneal nerve

      Explanation:

      The lower infero-lateral aspect of the fossa is where the sural nerve exits, and it is at a higher risk during short saphenous vein surgery. On the other hand, the tibial nerve is located more medially and is less susceptible to injury in this area.

      Anatomy of the Popliteal Fossa

      The popliteal fossa is a diamond-shaped space located at the back of the knee joint. It is bound by various muscles and ligaments, including the biceps femoris, semimembranosus, semitendinosus, and gastrocnemius. The floor of the popliteal fossa is formed by the popliteal surface of the femur, posterior ligament of the knee joint, and popliteus muscle, while the roof is made up of superficial and deep fascia.

      The popliteal fossa contains several important structures, including the popliteal artery and vein, small saphenous vein, common peroneal nerve, tibial nerve, posterior cutaneous nerve of the thigh, genicular branch of the obturator nerve, and lymph nodes. These structures are crucial for the proper functioning of the lower leg and foot.

      Understanding the anatomy of the popliteal fossa is important for healthcare professionals, as it can help in the diagnosis and treatment of various conditions affecting the knee joint and surrounding structures.

    • This question is part of the following fields:

      • Cardiovascular System
      26.6
      Seconds
  • Question 4 - A 50-year-old man presents to the emergency department with excruciating chest pain that...

    Incorrect

    • A 50-year-old man presents to the emergency department with excruciating chest pain that raises suspicion of aortic dissection. Which layers are the blood expected to be flowing between?

      Your Answer: Tunica media and tunica adventitia

      Correct Answer: Tunica intima and tunica media

      Explanation:

      In an aortic dissection, the tunica intima becomes separated from the tunica media. The tunica intima is the innermost layer of a blood vessel, while the tunica media is the second layer and the tunica adventitia is the third layer. Normally, the tunica media would be situated between the tunica intima and adventitia in the aorta. Capillaries have layers called endothelium and basal laminae, while the internal and external elastic laminae are found on either side of the tunica media.

      Artery Histology: Layers of Blood Vessel Walls

      The wall of a blood vessel is composed of three layers: the tunica intima, tunica media, and tunica adventitia. The innermost layer, the tunica intima, is made up of endothelial cells that are separated by gap junctions. The middle layer, the tunica media, contains smooth muscle cells and is separated from the intima by the internal elastic lamina and from the adventitia by the external elastic lamina. The outermost layer, the tunica adventitia, contains the vasa vasorum, fibroblast, and collagen. This layer is responsible for providing support and protection to the blood vessel. The vasa vasorum are small blood vessels that supply oxygen and nutrients to the larger blood vessels. The fibroblast and collagen provide structural support to the vessel wall. Understanding the histology of arteries is important in diagnosing and treating various cardiovascular diseases.

    • This question is part of the following fields:

      • Cardiovascular System
      20.9
      Seconds
  • Question 5 - A 35-year-old man comes to the clinic complaining of occasional palpitations and feeling...

    Incorrect

    • A 35-year-old man comes to the clinic complaining of occasional palpitations and feeling lightheaded. He reports no chest pain, shortness of breath, or swelling in his legs. Upon examination, no abnormalities are found. An ECG reveals a shortened PR interval and the presence of delta waves. What is the underlying pathophysiology of the most likely diagnosis?

      Your Answer: Sodium channelopathy

      Correct Answer: Accessory pathway

      Explanation:

      The presence of intermittent palpitations and lightheadedness can be indicative of various conditions, but the detection of a shortened PR interval and delta wave on an ECG suggests the possibility of Wolff-Parkinson-White syndrome. This syndrome arises from an additional pathway connecting the atrium and ventricle.

      Understanding Wolff-Parkinson White Syndrome

      Wolff-Parkinson White (WPW) syndrome is a condition that occurs due to a congenital accessory conducting pathway between the atria and ventricles, leading to atrioventricular re-entry tachycardia (AVRT). This condition can cause AF to degenerate rapidly into VF as the accessory pathway does not slow conduction. The ECG features of WPW include a short PR interval, wide QRS complexes with a slurred upstroke known as a delta wave, and left or right axis deviation depending on the location of the accessory pathway. WPW is associated with various conditions such as HOCM, mitral valve prolapse, Ebstein’s anomaly, thyrotoxicosis, and secundum ASD.

      The definitive treatment for WPW is radiofrequency ablation of the accessory pathway. Medical therapy options include sotalol, amiodarone, and flecainide. However, sotalol should be avoided if there is coexistent atrial fibrillation as it may increase the ventricular rate and potentially deteriorate into ventricular fibrillation. WPW can be differentiated into type A and type B based on the presence or absence of a dominant R wave in V1. It is important to understand WPW and its associations to provide appropriate management and prevent potential complications.

    • This question is part of the following fields:

      • Cardiovascular System
      37.8
      Seconds
  • Question 6 - A 79-year-old man presents to a heart failure clinic with worsening peripheral oedema...

    Incorrect

    • A 79-year-old man presents to a heart failure clinic with worsening peripheral oedema and seeks advice on potential treatment options. The patient has a medical history of heart failure with reduced ejection fraction and chronic kidney disease. His current medication regimen includes ramipril, bisoprolol, atorvastatin, and furosemide.

      The patient's laboratory results show a sodium level of 139 mmol/L (135 - 145), potassium level of 3.6 mmol/L (3.5 - 5.0), bicarbonate level of 24 mmol/L (22 - 29), urea level of 7.4 mmol/L (2.0 - 7.0), creatinine level of 132 µmol/L (55 - 120), and an estimated glomerular filtration rate (eGFR) of 53 ml/min/1.73m2 (>60).

      What adjustments should be made to the patient's furosemide treatment?

      Your Answer: Change to amlodipine

      Correct Answer: Increase the dose

      Explanation:

      To ensure sufficient concentration of loop diuretics within the tubules, patients with poor renal function may require increased doses. This is because loop diuretics, such as furosemide, work by inhibiting the Na-K-Cl cotransporter in the thick ascending limb of the loop of Henle, which reduces the absorption of NaCl. As these diuretics work on the apical membrane, they must first be filtered into the tubules by the glomerulus before they can have an effect. Therefore, increasing the dose can help achieve the desired concentration within the tubules. The other options, such as changing to amlodipine, keeping the dose the same, or stopping immediately, are not appropriate in this scenario.

      Loop Diuretics: Mechanism of Action and Clinical Applications

      Loop diuretics, such as furosemide and bumetanide, are medications that inhibit the Na-K-Cl cotransporter (NKCC) in the thick ascending limb of the loop of Henle. By doing so, they reduce the absorption of NaCl, resulting in increased urine output. Loop diuretics act on NKCC2, which is more prevalent in the kidneys. These medications work on the apical membrane and must first be filtered into the tubules by the glomerulus before they can have an effect. Patients with poor renal function may require higher doses to ensure sufficient concentration in the tubules.

      Loop diuretics are commonly used in the treatment of heart failure, both acutely (usually intravenously) and chronically (usually orally). They are also indicated for resistant hypertension, particularly in patients with renal impairment. However, loop diuretics can cause adverse effects such as hypotension, hyponatremia, hypokalemia, hypomagnesemia, hypochloremic alkalosis, ototoxicity, hypocalcemia, renal impairment, hyperglycemia (less common than with thiazides), and gout. Therefore, careful monitoring of electrolyte levels and renal function is necessary when using loop diuretics.

    • This question is part of the following fields:

      • Cardiovascular System
      106.7
      Seconds
  • Question 7 - An individual in their mid-20s is identified to have a superior vena cava...

    Incorrect

    • An individual in their mid-20s is identified to have a superior vena cava on the left side. What is the most probable route for blood from this system to reach the heart?

      Your Answer: Via the azygos venous system and into the superior vena cava

      Correct Answer: Via the coronary sinus

      Explanation:

      The Superior Vena Cava: Anatomy, Relations, and Developmental Variations

      The superior vena cava (SVC) is a large vein that drains blood from the head and neck, upper limbs, thorax, and part of the abdominal walls. It is formed by the union of the subclavian and internal jugular veins, which then join to form the right and left brachiocephalic veins. The SVC is located in the anterior margins of the right lung and pleura, and is related to the trachea and right vagus nerve posteromedially, and the posterior aspects of the right lung and pleura posterolaterally. The pulmonary hilum is located posteriorly, while the right phrenic nerve and pleura are located laterally on the right side, and the brachiocephalic artery and ascending aorta are located laterally on the left side.

      Developmental variations of the SVC are recognized, including anomalies of its connection and interruption of the inferior vena cava (IVC) in its abdominal course. In some individuals, a persistent left-sided SVC may drain into the right atrium via an enlarged orifice of the coronary sinus, while in rare cases, the left-sided vena cava may connect directly with the superior aspect of the left atrium, usually associated with an un-roofing of the coronary sinus. Interruption of the IVC may occur in patients with left-sided atrial isomerism, with drainage achieved via the azygos venous system.

      Overall, understanding the anatomy, relations, and developmental variations of the SVC is important for medical professionals in diagnosing and treating related conditions.

    • This question is part of the following fields:

      • Cardiovascular System
      32.5
      Seconds
  • Question 8 - A 50-year-old UK born patient with end-stage kidney failure arrives at the emergency...

    Incorrect

    • A 50-year-old UK born patient with end-stage kidney failure arrives at the emergency department complaining of sharp chest pain that subsides when sitting forward. The patient has not undergone dialysis yet. Upon conducting an ECG, it is observed that there is a widespread 'saddle-shaped' ST elevation and PR depression, leading to a diagnosis of pericarditis. What could be the probable cause of this pericarditis?

      Your Answer: Post-myocardial infarction

      Correct Answer: Uraemia

      Explanation:

      There is no indication of trauma in patients with advanced renal failure prior to dialysis initiation.

      ECG results do not indicate a recent heart attack.

      The patient’s age decreases the likelihood of malignancy.

      Acute Pericarditis: Causes, Features, Investigations, and Management

      Acute pericarditis is a possible diagnosis for patients presenting with chest pain. The condition is characterized by chest pain, which may be pleuritic and relieved by sitting forwards. Other symptoms include non-productive cough, dyspnoea, and flu-like symptoms. Tachypnoea and tachycardia may also be present, along with a pericardial rub.

      The causes of acute pericarditis include viral infections, tuberculosis, uraemia, trauma, post-myocardial infarction, Dressler’s syndrome, connective tissue disease, hypothyroidism, and malignancy.

      Investigations for acute pericarditis include ECG changes, which are often global/widespread, as opposed to the ‘territories’ seen in ischaemic events. The ECG may show ‘saddle-shaped’ ST elevation and PR depression, which is the most specific ECG marker for pericarditis. All patients with suspected acute pericarditis should have transthoracic echocardiography.

      Management of acute pericarditis involves treating the underlying cause. A combination of NSAIDs and colchicine is now generally used as first-line treatment for patients with acute idiopathic or viral pericarditis.

      In summary, acute pericarditis is a possible diagnosis for patients presenting with chest pain. The condition is characterized by chest pain, which may be pleuritic and relieved by sitting forwards, along with other symptoms. The causes of acute pericarditis are varied, and investigations include ECG changes and transthoracic echocardiography. Management involves treating the underlying cause and using a combination of NSAIDs and colchicine as first-line treatment.

    • This question is part of the following fields:

      • Cardiovascular System
      21.3
      Seconds
  • Question 9 - A 67-year-old man with heart failure visits his physician and inquires about the...

    Incorrect

    • A 67-year-old man with heart failure visits his physician and inquires about the factors that influence stroke volume. What interventions can enhance stroke volume in a healthy person?

      Your Answer: Hypertension

      Correct Answer: Increased central venous pressure

      Explanation:

      There are four factors that impact stroke volume: cardiac size, contractility, preload, and afterload. When someone has heart failure, their stroke volume decreases. If there is an increase in parasympathetic activation, it would lead to a reduction in contractility. Hypertension would increase afterload, which means the ventricle would have to work harder to pump blood into the aorta. If there is an increase in central venous pressure, it would lead to an increase in preload due to an increase in venous return.

      The stroke volume refers to the amount of blood that is pumped out of the ventricle during each cycle of cardiac contraction. This volume is usually the same for both ventricles and is approximately 70ml for a man weighing 70Kg. To calculate the stroke volume, the end systolic volume is subtracted from the end diastolic volume. Several factors can affect the stroke volume, including the size of the heart, its contractility, preload, and afterload.

    • This question is part of the following fields:

      • Cardiovascular System
      21.6
      Seconds
  • Question 10 - As a curious fourth-year medical student, you observe the birth of a full-term...

    Incorrect

    • As a curious fourth-year medical student, you observe the birth of a full-term baby delivered vaginally to a mother who has given birth once before. The infant's Apgar score is 9 at 1 minute and 10 at 10 minutes, and the delivery is uncomplicated. However, a postnatal examination reveals that the ductus arteriosus has not closed properly. Can you explain the process by which this structure normally closes?

      Your Answer: Increased oxygen tension which increases the concentration of prostaglandins

      Correct Answer: Decreased prostaglandin concentration

      Explanation:

      The ductus arteriosus, which is a shunt connecting the pulmonary artery with the descending aorta in utero, closes with the first breaths of life. This is due to an increase in pulmonary blood flow, which helps to clear local vasodilating prostaglandins that keep the duct open during fetal development. The opening of the lung alveoli with the first breath of life leads to an increase in oxygen tension in the blood, but this is not the primary mechanism behind the closure of the ductus arteriosus. It is important to note that oxygen tension in the blood increases after birth when the infant breathes in air and no longer receives mixed oxygenated blood via the placenta.

      Understanding Patent Ductus Arteriosus

      Patent ductus arteriosus is a type of congenital heart defect that is generally classified as ‘acyanotic’. However, if left uncorrected, it can eventually result in late cyanosis in the lower extremities, which is termed differential cyanosis. This condition is caused by a connection between the pulmonary trunk and descending aorta. Normally, the ductus arteriosus closes with the first breaths due to increased pulmonary flow, which enhances prostaglandins clearance. However, in some cases, this connection remains open, leading to patent ductus arteriosus.

      This condition is more common in premature babies, those born at high altitude, or those whose mothers had rubella infection in the first trimester. The features of patent ductus arteriosus include a left subclavicular thrill, continuous ‘machinery’ murmur, large volume, bounding, collapsing pulse, wide pulse pressure, and heaving apex beat.

      The management of patent ductus arteriosus involves the use of indomethacin or ibuprofen, which are given to the neonate. These medications inhibit prostaglandin synthesis and close the connection in the majority of cases. If patent ductus arteriosus is associated with another congenital heart defect amenable to surgery, then prostaglandin E1 is useful to keep the duct open until after surgical repair. Understanding patent ductus arteriosus is important for early diagnosis and management of this condition.

    • This question is part of the following fields:

      • Cardiovascular System
      25.9
      Seconds
  • Question 11 - A 55-year-old male with hypertension visits his GP complaining of a persistent dry...

    Incorrect

    • A 55-year-old male with hypertension visits his GP complaining of a persistent dry cough. He reports that this started two weeks ago after he was prescribed ramipril. What alternative medication class might the GP consider switching him to?

      Your Answer: Calcium channel blockers

      Correct Answer: Angiotensin receptor blockers

      Explanation:

      A dry cough is a common and bothersome side effect of ACE inhibitors like ramipril. However, angiotensin receptor blockers work by blocking angiotensin II receptors and have similar adverse effects to ACE inhibitors, but without the cough. According to guidelines, ACE inhibitors are the first line of treatment for white patients under 55 years old. If they are ineffective, angiotensin receptor blockers should be used instead. Beta-blockers, diuretics, calcium channel blockers, and alpha blockers are reserved for later use.

      Angiotensin-converting enzyme (ACE) inhibitors are commonly used as the first-line treatment for hypertension and heart failure in younger patients. However, they may not be as effective in treating hypertensive Afro-Caribbean patients. ACE inhibitors are also used to treat diabetic nephropathy and prevent ischaemic heart disease. These drugs work by inhibiting the conversion of angiotensin I to angiotensin II and are metabolized in the liver.

      While ACE inhibitors are generally well-tolerated, they can cause side effects such as cough, angioedema, hyperkalaemia, and first-dose hypotension. Patients with certain conditions, such as renovascular disease, aortic stenosis, or hereditary or idiopathic angioedema, should use ACE inhibitors with caution or avoid them altogether. Pregnant and breastfeeding women should also avoid these drugs.

      Patients taking high-dose diuretics may be at increased risk of hypotension when using ACE inhibitors. Therefore, it is important to monitor urea and electrolyte levels before and after starting treatment, as well as any changes in creatinine and potassium levels. Acceptable changes include a 30% increase in serum creatinine from baseline and an increase in potassium up to 5.5 mmol/l. Patients with undiagnosed bilateral renal artery stenosis may experience significant renal impairment when using ACE inhibitors.

      The current NICE guidelines recommend using a flow chart to manage hypertension, with ACE inhibitors as the first-line treatment for patients under 55 years old. However, individual patient factors and comorbidities should be taken into account when deciding on the best treatment plan.

    • This question is part of the following fields:

      • Cardiovascular System
      9.3
      Seconds
  • Question 12 - A 70-year-old female is brought to the Emergency department with a severe crushing...

    Correct

    • A 70-year-old female is brought to the Emergency department with a severe crushing chest pain that was alleviated by sublingual GTN. The medical team diagnoses her with acute coronary syndrome (ACS). What test can distinguish between unstable angina and non-ST elevation MI (NSTEMI), both of which are types of ACS?

      Your Answer: Troponin level

      Explanation:

      Acute Coronary Syndrome

      Acute coronary syndrome is a term used to describe a range of conditions that affect the heart, including unstable angina, non-ST elevation MI (NSTEMI), and ST elevation MI (STEMI). The detection of raised cardiac enzymes is the definitive test in distinguishing between NSTEMI and unstable angina. If the enzymes are raised, it indicates myocardial tissue infarction, which is present in NSTEMI but not in unstable angina. Clinical history and exercise ECG testing are also important in distinguishing between these conditions. It is important to understand the differences between these conditions in order to provide appropriate treatment and management.

    • This question is part of the following fields:

      • Cardiovascular System
      51.9
      Seconds
  • Question 13 - A 54-year-old man is admitted to the coronary care unit after being hospitalized...

    Incorrect

    • A 54-year-old man is admitted to the coronary care unit after being hospitalized three weeks ago for an ST-elevation myocardial infarction. He reports chest pain again and is concerned it may be another infarction. The pain is described as sharp and worsens with breathing. The cardiology resident notes a fever and hears a rubbing sound and pansystolic murmur on auscultation, which were previously present. A 12-lead ECG shows no new ischemic changes. The patient has a history of diabetes, hypertension, and heavy smoking since his teenage years. What is the most likely cause of his current condition?

      Your Answer: Bacterial infection

      Correct Answer: Autoimmune-mediated

      Explanation:

      Dressler’s syndrome is an autoimmune-mediated pericarditis that occurs 2-6 weeks after a myocardial infarction (MI). This patient, who has been admitted to the coronary care unit following an MI, is experiencing chest pain that is pleuritic in nature, along with fever and a friction rub sound upon examination. Given the timing of the symptoms at three weeks post-MI, Dressler’s syndrome is the most likely diagnosis. This condition results from an autoimmune-mediated inflammatory reaction to antigens following an MI, leading to inflammation of the pericardial sac and pericardial effusion. If left untreated, it can increase the risk of ventricular rupture. Treatment typically involves high-dose aspirin and corticosteroids if necessary.

      Myocardial infarction (MI) can lead to various complications, which can occur immediately, early, or late after the event. Cardiac arrest is the most common cause of death following MI, usually due to ventricular fibrillation. Cardiogenic shock may occur if a large part of the ventricular myocardium is damaged, and it is difficult to treat. Chronic heart failure may result from ventricular myocardium dysfunction, which can be managed with loop diuretics, ACE-inhibitors, and beta-blockers. Tachyarrhythmias, such as ventricular fibrillation and ventricular tachycardia, are common complications. Bradyarrhythmias, such as atrioventricular block, are more common following inferior MI. Pericarditis is common in the first 48 hours after a transmural MI, while Dressler’s syndrome may occur 2-6 weeks later. Left ventricular aneurysm and free wall rupture, ventricular septal defect, and acute mitral regurgitation are other complications that may require urgent medical attention.

    • This question is part of the following fields:

      • Cardiovascular System
      25.2
      Seconds
  • Question 14 - A 57-year-old patient is being evaluated on the ward 3 days after experiencing...

    Incorrect

    • A 57-year-old patient is being evaluated on the ward 3 days after experiencing a transmural myocardial infarction (MI). The patient reports experiencing sharp, severe retrosternal chest pain that worsens with inspiration.

      During the assessment, the patient's vital signs are heart rate 82 beats/min, BP 132/90 mmHg, temperature 37.8ºC, and oxygen saturation 97% on room air. Upon auscultation, a pericardial friction rub is audible.

      What is the histological change in the myocardial tissue that is consistent with this presentation?

      Your Answer: Fat necrosis with basophil infiltration

      Correct Answer: Coagulative necrosis with neutrophil infiltration

      Explanation:

      Myocardial infarction (MI) can lead to various complications, which can occur immediately, early, or late after the event. Cardiac arrest is the most common cause of death following MI, usually due to ventricular fibrillation. Cardiogenic shock may occur if a large part of the ventricular myocardium is damaged, and it is difficult to treat. Chronic heart failure may result from ventricular myocardium dysfunction, which can be managed with loop diuretics, ACE-inhibitors, and beta-blockers. Tachyarrhythmias, such as ventricular fibrillation and ventricular tachycardia, are common complications. Bradyarrhythmias, such as atrioventricular block, are more common following inferior MI. Pericarditis is common in the first 48 hours after a transmural MI, while Dressler’s syndrome may occur 2-6 weeks later. Left ventricular aneurysm and free wall rupture, ventricular septal defect, and acute mitral regurgitation are other complications that may require urgent medical attention.

    • This question is part of the following fields:

      • Cardiovascular System
      23.1
      Seconds
  • Question 15 - A 67-year-old man presents to the emergency department with chest pain. He describes...

    Incorrect

    • A 67-year-old man presents to the emergency department with chest pain. He describes this as crushing central chest pain which is associated with nausea and sweating.

      Blood results are as follows:

      Hb 148 g/L Male: (135-180)
      Female: (115 - 160)
      Platelets 268 * 109/L (150 - 400)
      WBC 14.6 * 109/L (4.0 - 11.0)
      Na+ 136 mmol/L (135 - 145)
      K+ 4.7 mmol/L (3.5 - 5.0)
      Urea 6.2 mmol/L (2.0 - 7.0)
      Creatinine 95 µmol/L (55 - 120)
      Troponin 4058 ng/L (< 14 ng/L)

      An ECG is performed which demonstrates:

      Current ECG Sinus rhythm, QRS 168ms, dominant S wave in V1
      Previous ECG 12 months ago No abnormality

      Which part of the heart's conduction system is likely to be affected?

      Your Answer: SA node

      Correct Answer: Purkinje fibres

      Explanation:

      The Purkinje fibres have the highest conduction velocities in the heart, and a prolonged QRS (>120ms) with a dominant S wave in V1 may indicate left bundle branch block (LBBB). If a patient presents with chest pain, a raised troponin, and a previously normal ECG, LBBB should be considered as a possible cause and managed as an acute STEMI. LBBB is caused by damage to the left bundle branch and its associated Purkinje fibres.

      Understanding the Cardiac Action Potential and Conduction Velocity

      The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.

      Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.

    • This question is part of the following fields:

      • Cardiovascular System
      62.4
      Seconds
  • Question 16 - A 40-year-old male patient complains of shortness of breath, weight loss, and night...

    Incorrect

    • A 40-year-old male patient complains of shortness of breath, weight loss, and night sweats for the past six weeks. Despite being generally healthy, he is experiencing these symptoms. During the examination, the patient's fingers show clubbing, and his temperature is 37.8°C. His pulse is 88 beats per minute, and his blood pressure is 128/80 mmHg. Upon listening to his heart, a pansystolic murmur is audible. What signs are likely to be found in this patient?

      Your Answer: Cervical lymphadenopathy

      Correct Answer: Splinter haemorrhages

      Explanation:

      Symptoms and Diagnosis of Infective Endocarditis

      This individual has a lengthy medical history of experiencing night sweats and has developed clubbing of the fingers, along with a murmur. These symptoms are indicative of infective endocarditis. In addition to splinter hemorrhages in the nails, other symptoms that may be present include Roth spots in the eyes, Osler’s nodes and Janeway lesions in the palms and fingers of the hands, and splenomegaly instead of cervical lymphadenopathy. Cyanosis is not typically associated with clubbing and may suggest idiopathic pulmonary fibrosis or cystic fibrosis in younger individuals. However, this individual has no prior history of cystic fibrosis and has only been experiencing symptoms for six weeks.

    • This question is part of the following fields:

      • Cardiovascular System
      44.9
      Seconds
  • Question 17 - A 44-year-old male presents to the hospital with a headache and blurry vision...

    Incorrect

    • A 44-year-old male presents to the hospital with a headache and blurry vision that started two hours ago. He appears drowsy but is oriented to time, place, and person. He has no history of similar episodes and cannot recall the last time he saw a doctor. He denies any chest pain or shortness of breath. His respiratory rate is 16 breaths per minute, heart rate is 91 beats per minute, and blood pressure is 185/118 mmHg. A random blood glucose level is 6.1 mmol/l. The physician decides to initiate treatment with hydralazine, the only available drug at the time. How does this medication work in this patient?

      Your Answer: It blocks the opening of the voltage-dependent calcium channels in the smooth muscle leader to a decrease in the peripheral vascular resistance

      Correct Answer: It elevates the levels of cyclic GMP leading to a relaxation of the smooth muscle to a greater extent in the arterioles than the veins

      Explanation:

      Hydralazine is a medication commonly used in the acute setting to lower blood pressure. It works by increasing the levels of cyclic GMP, which leads to smooth muscle relaxation. This effect is more pronounced in the arterioles than the veins. The increased levels of cyclic GMP activate protein kinase G, which phosphorylates and activates myosin light chain phosphatase. This prevents the smooth muscle from contracting, resulting in vasodilation. This mechanism of action is different from calcium channel blockers such as amlodipine, which work by blocking calcium channels. Nitroprusside is another medication that increases cyclic GMP levels, but it is not mentioned as an option in this scenario.

      Hydralazine: An Antihypertensive with Limited Use

      Hydralazine is an antihypertensive medication that is not commonly used nowadays. It is still prescribed for severe hypertension and hypertension in pregnancy. The drug works by increasing cGMP, which leads to smooth muscle relaxation. However, there are certain contraindications to its use, such as systemic lupus erythematosus and ischaemic heart disease/cerebrovascular disease.

      Despite its potential benefits, hydralazine can cause adverse effects such as tachycardia, palpitations, flushing, fluid retention, headache, and drug-induced lupus. Therefore, it is not the first choice for treating hypertension in most cases. Overall, hydralazine is an older medication that has limited use due to its potential side effects and newer, more effective antihypertensive options available.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 18 - A patient with a history of aortic stenosis presents with anaemia. Is there...

    Correct

    • A patient with a history of aortic stenosis presents with anaemia. Is there a rare association with aortic stenosis that could explain the anaemia in this patient? This is particularly relevant for elderly patients.

      Your Answer: Angiodysplasia

      Explanation:

      Aortic Stenosis and Angiodysplasia: A Possible Association

      There have been numerous reports suggesting a possible link between aortic stenosis and angiodysplasia, which can result in blood loss and anemia. The exact mechanism behind this association is not yet fully understood. However, it is worth noting that replacing the stenotic valve often leads to the resolution of gastrointestinal blood loss. This finding highlights the importance of early detection and management of aortic stenosis, as it may prevent the development of angiodysplasia and its associated complications. Further research is needed to fully elucidate the relationship between these two conditions and to identify potential therapeutic targets.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 19 - A 36-year-old male comes to his GP complaining of chest pain that has...

    Correct

    • A 36-year-old male comes to his GP complaining of chest pain that has been present for a week. The pain worsens when he breathes in and is relieved when he sits forward. He also has a non-productive cough. He recently had a viral infection. An ECG was performed and showed global saddle-shaped ST elevation.

      Your Answer: Acute pericarditis

      Explanation:

      Chest pain that is relieved by sitting or leaning forward is often a symptom of acute pericarditis. This condition is commonly caused by a viral infection and may also present with flu-like symptoms, non-productive cough, and dyspnea. ECG changes may show a saddle-shaped ST elevation.

      Cardiac tamponade, on the other hand, is characterized by Beck’s triad, which includes hypotension, raised JVP, and muffled heart sounds. Dyspnea and tachycardia may also be present.

      A myocardial infarction is unlikely if the chest pain has been present for a week, as it typically presents more acutely and with constant chest pain regardless of body positioning. ECG changes would also occur in specific territories rather than globally.

      A pneumothorax presents with sudden onset dyspnea, pleuritic chest pain, tachypnea, and sweating. No ECG changes would be observed.

      A pulmonary embolism typically presents with acute onset tachypnea, fever, tachycardia, and crackles. Signs of deep vein thrombosis may also be present.

      Acute Pericarditis: Causes, Features, Investigations, and Management

      Acute pericarditis is a possible diagnosis for patients presenting with chest pain. The condition is characterized by chest pain, which may be pleuritic and relieved by sitting forwards. Other symptoms include non-productive cough, dyspnoea, and flu-like symptoms. Tachypnoea and tachycardia may also be present, along with a pericardial rub.

      The causes of acute pericarditis include viral infections, tuberculosis, uraemia, trauma, post-myocardial infarction, Dressler’s syndrome, connective tissue disease, hypothyroidism, and malignancy.

      Investigations for acute pericarditis include ECG changes, which are often global/widespread, as opposed to the ‘territories’ seen in ischaemic events. The ECG may show ‘saddle-shaped’ ST elevation and PR depression, which is the most specific ECG marker for pericarditis. All patients with suspected acute pericarditis should have transthoracic echocardiography.

      Management of acute pericarditis involves treating the underlying cause. A combination of NSAIDs and colchicine is now generally used as first-line treatment for patients with acute idiopathic or viral pericarditis.

      In summary, acute pericarditis is a possible diagnosis for patients presenting with chest pain. The condition is characterized by chest pain, which may be pleuritic and relieved by sitting forwards, along with other symptoms. The causes of acute pericarditis are varied, and investigations include ECG changes and transthoracic echocardiography. Management involves treating the underlying cause and using a combination of NSAIDs and colchicine as first-line treatment.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 20 - A 56-year-old male is admitted to the hospital with increasing fatigue and difficulty...

    Correct

    • A 56-year-old male is admitted to the hospital with increasing fatigue and difficulty exercising. After undergoing various tests, including echocardiography and right heart catheterization, it is determined that he has pulmonary arterial hypertension (PAH) with a mean pulmonary artery pressure of 35 mmhg and a pulmonary capillary wedge pressure of 8mmhg. One of the medications prescribed for him is ambrisentan. What is the mechanism of action of this drug?

      Your Answer: Endothelin-1 receptor antagonist

      Explanation:

      Ambrisentan is an antagonist of endothelin-1 receptors, which are involved in vasoconstriction. In pulmonary arterial hypertension (PAH), the expression of endothelin-1 is increased, leading to constriction of blood vessels. Ambrisentan selectively targets ETA receptors found in vascular smooth muscle, reducing morbidity and mortality in PAH patients. Common side effects include peripheral edema, sinusitis, flushing, and nasal congestion. Prostacyclins like PGI2 can also be used to manage PPH by dilating blood vessels and inhibiting platelet aggregation. PGE2, an inflammatory mediator, is not used in PAH treatment. PDE inhibitors like sildenafil increase cGMP levels in pulmonary vessels, relaxing vascular smooth muscle and reducing pulmonary artery pressure.

      Pulmonary arterial hypertension (PAH) is a condition where the resting mean pulmonary artery pressure is equal to or greater than 25 mmHg. The pathogenesis of PAH is thought to involve endothelin. It is more common in females and typically presents between the ages of 30-50 years. PAH is diagnosed in the absence of chronic lung diseases such as COPD, although certain factors increase the risk. Around 10% of cases are inherited in an autosomal dominant fashion.

      The classical presentation of PAH is progressive exertional dyspnoea, but other possible features include exertional syncope, exertional chest pain, peripheral oedema, and cyanosis. Physical examination may reveal a right ventricular heave, loud P2, raised JVP with prominent ‘a’ waves, and tricuspid regurgitation.

      Management of PAH should first involve treating any underlying conditions. Acute vasodilator testing is central to deciding on the appropriate management strategy. If there is a positive response to acute vasodilator testing, oral calcium channel blockers may be used. If there is a negative response, prostacyclin analogues, endothelin receptor antagonists, or phosphodiesterase inhibitors may be used. Patients with progressive symptoms should be considered for a heart-lung transplant.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 21 - A 56-year-old woman visits the clinic complaining of swelling and heaviness in her...

    Incorrect

    • A 56-year-old woman visits the clinic complaining of swelling and heaviness in her right leg. She is concerned about the appearance of her leg and attributes the worsening of the heaviness to her job as a security officer, which requires her to stand for extended periods. The patient's height is 160 centimetres, and her weight is 85 kilograms. During the examination, the doctor observes spidery swellings on the inside of her thigh that extend to the back of her leg. Palpation reveals mild tenderness. The doctor has ordered a duplex ultrasound for further assessment and advised the patient to wear graduated compression stockings. What is the most probable cause of this patient's condition?

      Your Answer: Incompetency of deep venous valves

      Correct Answer: Incompetency of superficial venous valves

      Explanation:

      Varicose veins occur when the valves in the superficial veins become incompetent, leading to dilated and twisted veins. Risk factors include aging, prolonged standing, and obesity. Symptoms may include pain, itching, and cosmetic concerns, and severe cases can lead to complications such as ulcers and bleeding. Diagnosis is confirmed by duplex ultrasound, and treatment includes lifestyle modifications and compression stockings. Heart failure, deep venous valve incompetency, and leg skin infection are not causes of varicose veins.

      Understanding Varicose Veins

      Varicose veins are enlarged and twisted veins that occur when the valves in the veins become weak or damaged, causing blood to flow backward and pool in the veins. They are most commonly found in the legs and can be caused by various factors such as age, gender, pregnancy, obesity, and genetics. While many people seek treatment for cosmetic reasons, others may experience symptoms such as aching, throbbing, and itching. In severe cases, varicose veins can lead to skin changes, bleeding, superficial thrombophlebitis, and venous ulceration.

      To diagnose varicose veins, a venous duplex ultrasound is typically performed to detect retrograde venous flow. Treatment options vary depending on the severity of the condition. Conservative treatments such as leg elevation, weight loss, regular exercise, and compression stockings may be recommended for mild cases. However, patients with significant or troublesome symptoms, skin changes, or a history of bleeding or ulcers may require referral to a specialist for further evaluation and treatment. Possible treatments include endothermal ablation, foam sclerotherapy, or surgery.

      In summary, varicose veins are a common condition that can cause discomfort and cosmetic concerns. While many cases do not require intervention, it is important to seek medical attention if symptoms or complications arise. With proper diagnosis and treatment, patients can manage their condition and improve their quality of life.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 22 - Abnormal conduction in the heart can result in arrhythmias, which may be caused...

    Incorrect

    • Abnormal conduction in the heart can result in arrhythmias, which may be caused by reduced blood flow in the coronary arteries leading to hypoxia. This can slow depolarisation in phase 0, resulting in slower conduction speeds.

      What ion movement is responsible for the rapid depolarisation observed in the cardiac action potential?

      Your Answer: Calcium influx

      Correct Answer: Sodium influx

      Explanation:

      Rapid depolarization is caused by a rapid influx of sodium.

      During phase 2, the plateau period, calcium influx is responsible.

      To maintain the electrical gradient, there is potassium influx in phase 4, which is facilitated by inward rectifying K+ channels and the Na+/K+ ion exchange pump.

      Potassium efflux mainly occurs during phases 1 and 3.

      Understanding the Cardiac Action Potential and Conduction Velocity

      The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.

      Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 23 - A 26-year-old Afro-Caribbean woman comes to the Emergency Department complaining of dyspnoea and...

    Incorrect

    • A 26-year-old Afro-Caribbean woman comes to the Emergency Department complaining of dyspnoea and fatigue that has been going on for 2 days. She reports experiencing similar episodes repeatedly over the past few years. She has no other medical history.

      During the examination, you observe sporadic erythematous lesions on her shins and detect a pansystolic murmur. You request a chest x-ray, which reveals bilateral hilar lymphadenopathy and an enlarged heart.

      What additional symptom is linked to this ailment?

      Your Answer: Decreased serum ACE

      Correct Answer: Reduced ventricular ejection fraction

      Explanation:

      Patients with reduced ejection fraction heart failure (HF-rEF) usually experience systolic dysfunction, which refers to the impaired ability of the myocardium to contract during systole.

      Types of Heart Failure

      Heart failure is a clinical syndrome where the heart cannot pump enough blood to meet the body’s metabolic needs. It can be classified in multiple ways, including by ejection fraction, time, and left/right side. Patients with heart failure may have a normal or abnormal left ventricular ejection fraction (LVEF), which is measured using echocardiography. Reduced LVEF is typically defined as < 35 to 40% and is termed heart failure with reduced ejection fraction (HF-rEF), while preserved LVEF is termed heart failure with preserved ejection fraction (HF-pEF). Heart failure can also be described as acute or chronic, with acute heart failure referring to an acute exacerbation of chronic heart failure. Left-sided heart failure is more common and may be due to increased left ventricular afterload or preload, while right-sided heart failure is caused by increased right ventricular afterload or preload. High-output heart failure is another type of heart failure that occurs when a normal heart is unable to pump enough blood to meet the body's metabolic needs. By classifying heart failure in these ways, healthcare professionals can better understand the underlying causes and tailor treatment plans accordingly. It is important to note that many guidelines for the management of heart failure only cover HF-rEF patients and do not address the management of HF-pEF patients. Understanding the different types of heart failure can help healthcare professionals provide more effective care for their patients.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 24 - A 55-year-old male complains of central chest pain. During examination, a mitral regurgitation...

    Incorrect

    • A 55-year-old male complains of central chest pain. During examination, a mitral regurgitation murmur is detected. An ECG reveals ST elevation in leads V1 to V6, but no ST elevation is observed in leads II, III, and aVF. What is the diagnosis?

      Your Answer: Boerhaave's syndrome

      Correct Answer: Anterior myocardial infarct

      Explanation:

      An anterior MI is the most probable diagnosis, given the absence of ST changes in the inferior leads. Aortic dissection is therefore less probable.

      The following table displays the relationship between ECG changes and the affected coronary artery territories. Anteroseptal changes in V1-V4 indicate involvement of the left anterior descending artery, while inferior changes in II, III, and aVF suggest the right coronary artery is affected. Anterolateral changes in V4-6, I, and aVL may indicate involvement of either the left anterior descending or left circumflex artery, while lateral changes in I, aVL, and possibly V5-6 suggest the left circumflex artery is affected. Posterior changes in V1-3 may indicate a posterior infarction, which is typically caused by the left circumflex artery but can also be caused by the right coronary artery. Reciprocal changes of STEMI are often seen as horizontal ST depression, tall R waves, upright T waves, and a dominant R wave in V2. Posterior infarction is confirmed by ST elevation and Q waves in posterior leads (V7-9), usually caused by the left circumflex artery but also possibly the right coronary artery. It is important to note that a new LBBB may indicate acute coronary syndrome.

      Diagram showing the correlation between ECG changes and coronary territories in acute coronary syndrome.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 25 - Samantha is a 63-year-old female who has just been diagnosed with hypertension. Her...

    Correct

    • Samantha is a 63-year-old female who has just been diagnosed with hypertension. Her physician informs her that her average blood pressure is influenced by various bodily processes, such as heart function, nervous system activity, and blood vessel diameter. Assuming an average cardiac output (CO) of 4L/min, Samantha's mean arterial pressure (MAP) is recorded at 140mmHg during her examination.

      What is Samantha's systemic vascular resistance (SVR) based on these measurements?

      Your Answer: 35 mmhgâ‹…minâ‹…mL-1

      Explanation:

      The equation used to calculate systemic vascular resistance is SVR = MAP / CO. For example, if the mean arterial pressure (MAP) is 140 mmHg and the cardiac output (CO) is 4 mL/min, then the SVR would be 35 mmHgâ‹…minâ‹…mL-1. Although the theoretical equation for SVR is more complex, it is often simplified by assuming that central venous pressure (CVP) is negligible. However, in reality, MAP is typically measured directly or indirectly using arterial pressure measurements. The equation for calculating MAP at rest is MAP = diastolic pressure + 1/3(pulse pressure), where pulse pressure is calculated as systolic pressure minus diastolic pressure.

      Cardiovascular physiology involves the study of the functions and processes of the heart and blood vessels. One important measure of heart function is the left ventricular ejection fraction, which is calculated by dividing the stroke volume (the amount of blood pumped out of the left ventricle with each heartbeat) by the end diastolic LV volume (the amount of blood in the left ventricle at the end of diastole) and multiplying by 100%. Another key measure is cardiac output, which is the amount of blood pumped by the heart per minute and is calculated by multiplying stroke volume by heart rate.

      Pulse pressure is another important measure of cardiovascular function, which is the difference between systolic pressure (the highest pressure in the arteries during a heartbeat) and diastolic pressure (the lowest pressure in the arteries between heartbeats). Factors that can increase pulse pressure include a less compliant aorta (which can occur with age) and increased stroke volume.

      Finally, systemic vascular resistance is a measure of the resistance to blood flow in the systemic circulation and is calculated by dividing mean arterial pressure (the average pressure in the arteries during a heartbeat) by cardiac output. Understanding these measures of cardiovascular function is important for diagnosing and treating cardiovascular diseases.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 26 - A 63-year-old male presents with right sided hemiplegia. An MRI confirms a diagnosis...

    Incorrect

    • A 63-year-old male presents with right sided hemiplegia. An MRI confirms a diagnosis of a left sided partial anterior circulating stroke. He is treated with high dose aspirin for 14 days. He is then started on clopidogrel which he was unfortunately intolerant of. You therefore start him on dual aspirin and dipyridamole.

      What is the mechanism of action of dipyridamole?

      Your Answer: Direct thrombin inhibitors

      Correct Answer: Increases the effects of adenosine

      Explanation:

      Dipyridamole is a medication that inhibits phosphodiesterase enzymes and reduces the uptake of adenosine by cells. This leads to an increase in adenosine levels and a decrease in the breakdown of cAMP. Patients taking dipyridamole should not receive exogenous adenosine treatment, such as for supraventricular tachycardia, due to this interaction.

      Clopidogrel is a medication that blocks ADP receptors.

      Aspirin is a medication that inhibits cyclo-oxygenase.

      Dabigatran and bivalirudin are medications that directly inhibit thrombin.

      Tirofiban and abciximab are medications that inhibit glycoprotein IIb/IIIa.

      Warfarin inhibits the production of factors II, VII, IX, and X.

      Understanding the Mechanism of Action of Dipyridamole

      Dipyridamole is a medication that is commonly used in combination with aspirin to prevent the formation of blood clots after a stroke or transient ischemic attack. The drug works by inhibiting phosphodiesterase, which leads to an increase in the levels of cyclic adenosine monophosphate (cAMP) in platelets. This, in turn, reduces the levels of intracellular calcium, which is necessary for platelet activation and aggregation.

      Apart from its antiplatelet effects, dipyridamole also reduces the cellular uptake of adenosine, a molecule that plays a crucial role in regulating blood flow and oxygen delivery to tissues. By inhibiting the uptake of adenosine, dipyridamole can increase its levels in the bloodstream, leading to vasodilation and improved blood flow.

      Another mechanism of action of dipyridamole is the inhibition of thromboxane synthase, an enzyme that is involved in the production of thromboxane A2, a potent platelet activator. By blocking this enzyme, dipyridamole can further reduce platelet activation and aggregation, thereby preventing the formation of blood clots.

      In summary, dipyridamole exerts its antiplatelet effects through multiple mechanisms, including the inhibition of phosphodiesterase, the reduction of intracellular calcium levels, the inhibition of thromboxane synthase, and the modulation of adenosine uptake. These actions make it a valuable medication for preventing thrombotic events in patients with a history of stroke or transient ischemic attack.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 27 - A 47-year-old woman is recuperating in the ICU after undergoing a Whipples surgery....

    Incorrect

    • A 47-year-old woman is recuperating in the ICU after undergoing a Whipples surgery. She has a central venous line inserted. What will cause the 'y' descent on the waveform trace?

      Your Answer: Opening of the pulmonary valve

      Correct Answer: Emptying of the right atrium

      Explanation:

      The JVP waveform consists of 3 upward deflections and 2 downward deflections. The upward deflections include the a wave, which represents atrial contraction, the c wave, which represents ventricular contraction, and the v wave, which represents atrial venous filling. The downward deflections include the x wave, which occurs when the atrium relaxes and the tricuspid valve moves down, and the y wave, which represents ventricular filling. The y descent in the waveform indicates the emptying of the atrium and the filling of the right ventricle.

      The heart has four chambers and generates pressures of 0-25 mmHg on the right side and 0-120 mmHg on the left. The cardiac output is the product of heart rate and stroke volume, typically 5-6L per minute. The cardiac impulse is generated in the sino atrial node and conveyed to the ventricles via the atrioventricular node. Parasympathetic and sympathetic fibers project to the heart via the vagus and release acetylcholine and noradrenaline, respectively. The cardiac cycle includes mid diastole, late diastole, early systole, late systole, and early diastole. Preload is the end diastolic volume and afterload is the aortic pressure. Laplace’s law explains the rise in ventricular pressure during the ejection phase and why a dilated diseased heart will have impaired systolic function. Starling’s law states that an increase in end-diastolic volume will produce a larger stroke volume up to a point beyond which stroke volume will fall. Baroreceptor reflexes and atrial stretch receptors are involved in regulating cardiac output.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 28 - A 20-year-old man undergoes a routine ECG during his employment health check. The...

    Incorrect

    • A 20-year-old man undergoes a routine ECG during his employment health check. The ECG reveals sinus arrhythmia with varying P-P intervals and slight changes in the ventricular rate. The P waves exhibit normal morphology, and the P-R interval remains constant. The patient has a history of asthma and has been using inhalers more frequently due to an increase in running mileage. What is the probable cause of this rhythm, and how would you reassure the patient about the ECG results?

      Your Answer: Use of salbutamol inhaler before appointment

      Correct Answer: Ventricular rate changes with ventilation

      Explanation:

      Sinus arrhythmia is a natural occurrence that is commonly observed in young and healthy individuals. It is characterized by a fluctuation in heart rate during breathing, with an increase in heart rate during inhalation and a decrease during exhalation. This is due to a decrease in vagal tone during inspiration and an increase during expiration. The P-R interval remains constant, indicating no heart block, while the varying P-P intervals reflect changes in the ventricular heart rate.

      While anxiety may cause tachycardia, it cannot explain the fluctuation in P-P intervals. Similarly, salbutamol may cause a brief increase in heart rate, but this would not result in varying P-P and P-R intervals. In healthy and fit individuals, there should be no variation in the firing of the sino-atrial node.

      Understanding the Normal ECG

      The electrocardiogram (ECG) is a diagnostic tool used to assess the electrical activity of the heart. The normal ECG consists of several waves and intervals that represent different phases of the cardiac cycle. The P wave represents atrial depolarization, while the QRS complex represents ventricular depolarization. The ST segment represents the plateau phase of the ventricular action potential, and the T wave represents ventricular repolarization. The Q-T interval represents the time for both ventricular depolarization and repolarization to occur.

      The P-R interval represents the time between the onset of atrial depolarization and the onset of ventricular depolarization. The duration of the QRS complex is normally 0.06 to 0.1 seconds, while the duration of the P wave is 0.08 to 0.1 seconds. The Q-T interval ranges from 0.2 to 0.4 seconds depending upon heart rate. At high heart rates, the Q-T interval is expressed as a ‘corrected Q-T (QTc)’ by taking the Q-T interval and dividing it by the square root of the R-R interval.

      Understanding the normal ECG is important for healthcare professionals to accurately interpret ECG results and diagnose cardiac conditions. By analyzing the different waves and intervals, healthcare professionals can identify abnormalities in the electrical activity of the heart and provide appropriate treatment.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 29 - A man in his 50s arrives at the emergency department exhibiting signs of...

    Correct

    • A man in his 50s arrives at the emergency department exhibiting signs of a stroke. After undergoing a CT angiogram, it is revealed that there is a constriction in the artery that provides blood to the right common carotid.

      What is the name of the affected artery?

      Your Answer: Brachiocephalic artery

      Explanation:

      The largest branch from the aortic arch is the brachiocephalic artery, which originates from it. This artery gives rise to both the right subclavian artery and the right common carotid arteries. The brachiocephalic artery is supplied by the aortic arch, while the coronary arteries are supplied by the ascending aorta. Additionally, the coeliac trunk is a branch that stems from the abdominal aorta.

      The Brachiocephalic Artery: Anatomy and Relations

      The brachiocephalic artery is the largest branch of the aortic arch, originating at the apex of the midline. It ascends superiorly and posteriorly to the right, lying initially anterior to the trachea and then on its right-hand side. At the level of the sternoclavicular joint, it divides into the right subclavian and right common carotid arteries.

      In terms of its relations, the brachiocephalic artery is anterior to the sternohyoid, sterno-thyroid, thymic remnants, left brachiocephalic vein, and right inferior thyroid veins. Posteriorly, it is related to the trachea, right pleura, right lateral, right brachiocephalic vein, superior part of the SVC, left lateral, thymic remnants, origin of left common carotid, inferior thyroid veins, and trachea at a higher level.

      The brachiocephalic artery typically has no branches, but it may have the thyroidea ima artery. Understanding the anatomy and relations of the brachiocephalic artery is important for medical professionals, as it is a crucial vessel in the human body.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 30 - A 50-year-old man undergoes carotid endarterectomy surgery after experiencing a transient ischaemic attack....

    Incorrect

    • A 50-year-old man undergoes carotid endarterectomy surgery after experiencing a transient ischaemic attack. The procedure is successful with no complications. However, the patient develops new hoarseness of voice and loss of effective cough mechanism post-surgery. There are no notable findings upon examination of the oral cavity.

      Which structure has been affected by the surgery?

      Your Answer: Cranial nerve XI

      Correct Answer: Cranial nerve X

      Explanation:

      Speech is innervated by the vagus (X) nerve, so any damage to this nerve can cause speech problems. Injuries to one side of the vagus nerve can result in hoarseness and vocal cord paralysis on the same side, while bilateral injuries can lead to aphonia and stridor. Other symptoms of vagal disease may include dysphagia, loss of cough reflex, gastroparesis, and cardiovascular effects. The facial nerve (VII) may also be affected during carotid surgery, causing muscle weakness in facial expression. However, the vestibulocochlear nerve (VIII) is not involved in speech and would not be damaged during carotid surgery. The accessory nerve (XI) does not innervate speech muscles and is rarely affected during carotid surgery, causing weakness in shoulder elevation instead. Hypoglossal (XII) palsy is a rare complication of carotid surgery that causes tongue deviation towards the side of the lesion, but not voice hoarseness.

      The vagus nerve is responsible for a variety of functions and supplies structures from the fourth and sixth pharyngeal arches, as well as the fore and midgut sections of the embryonic gut tube. It carries afferent fibers from areas such as the pharynx, larynx, esophagus, stomach, lungs, heart, and great vessels. The efferent fibers of the vagus are of two main types: preganglionic parasympathetic fibers distributed to the parasympathetic ganglia that innervate smooth muscle of the innervated organs, and efferent fibers with direct skeletal muscle innervation, largely to the muscles of the larynx and pharynx.

      The vagus nerve arises from the lateral surface of the medulla oblongata and exits through the jugular foramen, closely related to the glossopharyngeal nerve cranially and the accessory nerve caudally. It descends vertically in the carotid sheath in the neck, closely related to the internal and common carotid arteries. In the mediastinum, both nerves pass posteroinferiorly and reach the posterior surface of the corresponding lung root, branching into both lungs. At the inferior end of the mediastinum, these plexuses reunite to form the formal vagal trunks that pass through the esophageal hiatus and into the abdomen. The anterior and posterior vagal trunks are formal nerve fibers that splay out once again, sending fibers over the stomach and posteriorly to the coeliac plexus. Branches pass to the liver, spleen, and kidney.

      The vagus nerve has various branches in the neck, including superior and inferior cervical cardiac branches, and the right recurrent laryngeal nerve, which arises from the vagus anterior to the first part of the subclavian artery and hooks under it to insert into the larynx. In the thorax, the left recurrent laryngeal nerve arises from the vagus on the aortic arch and hooks around the inferior surface of the arch, passing upwards through the superior mediastinum and lower part of the neck. In the abdomen, the nerves branch extensively, passing to the coeliac axis and alongside the vessels to supply the spleen, liver, and kidney.

    • This question is part of the following fields:

      • Cardiovascular System
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SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular System (8/30) 27%
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