Understanding Indications for Permanent Pacemaker Insertion

A third degree AV block, also known as complete heart block, occurs when the atria and ventricles contract independently of each other. This can lead to syncope, chest pain, or signs of heart failure. Definitive treatment is the insertion of a permanent pacemaker. Other arrhythmias that may require permanent pacing include type 2 second-degree heart block (Mobitz II), sick sinus syndrome, and symptomatic slow atrial fibrillation. Ventricular tachycardia and ventricular fibrillation are not indications for pacing. Type 1 second degree (Mobitz I) AV block is a benign condition that does not require specific treatment. It is important to understand these indications for permanent pacemaker insertion for both exam and clinical purposes.

Complications of Myocardial Infarction

Myocardial infarction (MI) is a serious medical condition that can lead to various complications. Among these complications, ventricular arrhythmia is the most common cause of death. Malignant ventricular arrhythmias require immediate direct current (DC) electrical therapy to terminate the arrhythmias. Mural thrombosis, although it may cause systemic emboli, is not a common cause of death. Myocardial wall rupture and muscular rupture typically occur 4-7 days post-infarction, while papillary muscle rupture is also a possibility. Pulmonary edema, which can be life-threatening, is accompanied by symptoms of breathlessness and orthopnea. However, it can be treated effectively with oxygen, positive pressure therapy, and vasodilators.

Understanding the Complications of Myocardial Infarction

Cardiac Conditions: Differentiating Left Atrial Myxoma from Other Pathologies

Left atrial myxoma is a cardiac condition characterized by heart sounds, systemic embolization, and intracardiac calcification seen on X-ray. Echocardiography is used to confirm the diagnosis, and surgery is usually curative. However, other cardiac pathologies can present with similar symptoms, including rheumatic heart disease, mitral stenosis, mitral regurgitation, and infective endocarditis. It is important to differentiate between these conditions to provide appropriate treatment. This article discusses the key features of each pathology to aid in diagnosis.

Acute Mesenteric Ischaemia

Acute mesenteric ischaemia is a condition that occurs when there is a disruption in blood flow to the small intestine or right colon. This can be caused by arterial or venous disease, with arterial disease further classified as non-occlusive or occlusive. The classic triad of symptoms associated with acute mesenteric ischaemia includes gastrointestinal emptying, abdominal pain, and underlying cardiac disease.

The hallmark symptom of mesenteric ischaemia is severe abdominal pain, which may be accompanied by other symptoms such as nausea, vomiting, abdominal distention, ileus, peritonitis, blood in the stool, and shock. Advanced ischaemia is characterized by the presence of these symptoms.

There are several risk factors associated with acute mesenteric ischaemia, including congestive heart failure, cardiac arrhythmias (especially atrial fibrillation), recent myocardial infarction, atherosclerosis, hypercoagulable states, and hypovolaemia. It is important to be aware of these risk factors and to seek medical attention promptly if any symptoms of acute mesenteric ischaemia are present.

Understanding the Relationship between Neck Veins and Various Medical Conditions

The appearance of neck veins can provide valuable information about a patient’s health. Here are some examples of how different medical conditions can affect the appearance of neck veins:

1. Constrictive pericarditis: This condition restricts the heart’s ability to expand, leading to higher pressures within the right heart. This can cause jugular venous distension, which is more pronounced during inspiration (Kussmaul’s sign).

2. Dehydration: A decrease in intravascular blood volume can cause flattened neck veins.

3. Venous insufficiency: Incompetent venous valves can lead to venous stasis and pooling of blood in the lower extremities. This can cause syncope due to decreased venous return to the heart.

4. Budd-Chiari syndrome and hepatic vein thrombosis: These conditions involve blood clots in the hepatic vein or inferior vena cava, which prevent blood from returning to the right heart from the abdomen and lower extremities. This decreases the pressure in the right heart and allows blood to drain more easily from the jugular and neck veins, resulting in flattened neck veins.

Understanding the relationship between neck veins and various medical conditions can aid in diagnosis and treatment.

Interpretation of Heart Sounds

Explanation: When listening to heart sounds, it is important to understand the physiological and pathological factors that can affect them. During inspiration, there is an increased return of blood to the right heart, which can prolong the closure of the pulmonary valve. This is a normal physiological response. Right-to-left shunting, on the other hand, can cause cyanosis and prolong the closure of the aortic valve. A stiff left ventricle, often seen in long-standing hypertension, can produce a third heart sound called S4, but this sound does not vary with inspiration. An atrial septal defect will cause fixed splitting of S2 and will not vary with inspiration. Therefore, understanding the underlying causes of heart sounds can aid in the diagnosis and management of cardiovascular conditions.

Common Heart Murmurs and Their Associations

Heart murmurs are abnormal sounds heard during a heartbeat. They can be innocent or pathological, and their characteristics can provide clues to the underlying condition. Here are some common heart murmurs and their associations:

1. Ejection systolic murmur (ESM): This murmur is associated with aortic stenosis and is related to the ventricular outflow tract. It may be innocent in children and high-output states, but pathological causes include aortic stenosis and sclerosis, pulmonary stenosis, and hypertrophic obstructive cardiomyopathy.

2. Mid-diastolic murmur: This murmur is commonly associated with tricuspid or mitral stenosis and starts after the second heart sound and ends before the first heart sound. Rheumatic fever is a common cause of mitral valve stenosis.

3. Pansystolic murmur: This murmur is associated with mitral regurgitation and is of uniform intensity that starts immediately after S1 and merges with S2. It is also found in tricuspid regurgitation and ventricular septal defects.

4. Early diastolic murmur (EDM): This high-pitched murmur occurs in pulmonary and aortic regurgitation and is caused by blood flowing through a dysfunctional valve back into the ventricle. It may be accentuated by asking the patient to lean forward.

5. Continuous murmur: This murmur is commonly associated with a patent ductus arteriosus (PDA), a connection between the aorta and the pulmonary artery. It causes a continuous murmur, sometimes described as a machinery murmur, heard throughout both systole and diastole.

Arteriosclerosis and Related Conditions

Arteriosclerosis is a medical condition that refers to the hardening and loss of elasticity of medium or large arteries. Atherosclerosis, on the other hand, is a specific type of arteriosclerosis that occurs when fatty materials such as cholesterol accumulate in the artery walls, causing them to thicken. This chronic inflammatory response is caused by the accumulation of macrophages and white blood cells, and is often promoted by low-density lipoproteins. The formation of multiple plaques within the arteries characterizes atherosclerosis.

Medial calcific sclerosis is another form of arteriosclerosis that occurs when calcium deposits form in the middle layer of walls of medium-sized vessels. This condition is often not clinically apparent unless it is severe, and it is more common in people over 50 years old and in diabetics. It can be seen as opaque vessels on radiographs.

Lymphatic obstruction, on the other hand, is a blockage of the lymph vessels that drain fluid from tissues throughout the body. This condition may cause lymphoedema, and the most common reason for this is the removal or enlargement of the lymph nodes.

It is important to understand these conditions and their differences to properly diagnose and treat patients.

Symptoms and Mortality Risk in Aortic Stenosis

Aortic stenosis is a serious condition that can lead to decreased cerebral perfusion and potentially fatal outcomes. Here are some common symptoms and their associated mortality risks:

– Syncope: This is a major concern and indicates the need for valve replacement, regardless of valve area.
– Chest pain: While angina can occur due to reduced diastolic coronary perfusion time and increased left ventricular mass, it is not as significant as syncope in predicting mortality.
– Cough: Aortic stenosis typically does not cause coughing.
– Palpitations: Unless confirmed to be non-sustained ventricular tachycardia, palpitations do not increase mortality risk.
– Orthostatic dizziness: Mild decreased cerebral perfusion can cause dizziness upon standing, but this symptom alone does not confer additional mortality risk.

It is important to be aware of these symptoms and seek medical attention if they occur, as aortic stenosis can be a life-threatening condition.

Heart Failure Medications: Prognostic and Symptomatic Benefits

Heart failure is a prevalent disease that can be managed with various medications. These medications can be divided into two categories: those with prognostic benefits and those with symptomatic benefits. Prognostic medications help improve long-term outcomes, while symptomatic medications provide relief from symptoms.

Prognostic medications include selective beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II antagonists, and spironolactone. In the RALES trial, spironolactone was shown to reduce all-cause mortality by 30% in patients with heart failure and an ejection fraction of less than 35%.

Symptomatic medications include loop diuretics, digoxin, and vasodilators such as nitrates and hydralazine. These medications provide relief from symptoms but do not improve long-term outcomes.

Other medications, such as nifedipine, sotalol, and naftidrofuryl, are used to manage other conditions such as angina, hypertension, and peripheral and cerebrovascular disorders, but are not of prognostic benefit in heart failure.

Treatment for heart failure can be tailored to each individual case, and heart transplant remains a limited option for certain patient groups. Understanding the benefits and limitations of different medications can help healthcare providers make informed decisions about the best course of treatment for their patients.

Understanding Different Types of Heart Blocks on an ECG

An electrocardiogram (ECG) is a diagnostic tool used to monitor the electrical activity of the heart. It can help identify different types of heart blocks, which occur when the electrical signals that control the heartbeat are disrupted. Here are some common types of heart blocks and how they appear on an ECG:

Second Degree Heart Block – Mobitz Type II
This type of heart block is characterized by a regular non-conducted P-wave on the ECG. It may also show a widened QRS, indicating that the block is in the bundle branches of Purkinje fibers. If a patient is symptomatic with Mobitz type II heart block, permanent pacing is required to prevent progression to third degree heart block.

Third Degree Heart Block
An ECG of a third degree heart block would show dissociated P-waves and QRS-waves. This means that the atria and ventricles are not communicating properly, and the heart may beat very slowly or irregularly.

Atrial Flutter
Atrial flutter on an ECG would typically show a saw-toothed baseline. This occurs when the atria are beating too quickly and not in sync with the ventricles.

Ectopic Beats
Ectopic beats are premature heartbeats that occur outside of the normal rhythm. They would not result in regular non-conducted P-waves on an ECG.

Second Degree Heart Block – Mobitz Type I
Mobitz type I heart block would typically show progressive lengthening of the PR interval over several complexes, before a non-conducted P-wave would occur. This type of heart block is usually not as serious as Mobitz type II, but may still require monitoring and treatment.

ECG Changes and Localisation of Infarct in Coronary Artery Disease

Patients with chest pain and multiple risk factors for cardiac disease require prompt evaluation to determine the underlying cause. Electrocardiogram (ECG) changes can help localise the infarct to a particular territory, which can aid in diagnosis and treatment.

Inferior infarcts are often due to lesions in the right coronary artery, as evidenced by ST elevation in leads II, III, and aVF. However, in 20% of cases, this can also be caused by an occlusion of a dominant left circumflex artery.

Lateral infarcts involve branches of the left anterior descending (LAD) and left circumflex arteries, and are characterised by ST elevation in leads I, aVL, and V5-6. It is unusual for a lateral STEMI to occur in isolation, and it usually occurs as part of a larger territory infarction.

Anterior infarcts are caused by blockage of the LAD artery, and are characterised by ST elevation in leads V1-V6.

Blockage of the right marginal artery does not have a specific pattern of ECG changes associated with it, and it is not one of the major coronary vessels.

In summary, understanding the ECG changes associated with different coronary arteries can aid in localising the infarct and guiding appropriate treatment.

Medical Triads and Laws

There are several medical triads and laws that are used to diagnose certain conditions. One of these is Beck’s triad, which consists of muffled or distant heart sounds, low systolic blood pressure, and distended neck veins. This triad is associated with cardiac tamponade.

Another law is Courvoisier’s law, which states that if a patient has a palpable gallbladder that is non-tender and is associated with painless jaundice, the cause is unlikely to be gallstones.

Meigs syndrome is a triad of ascites, pleural effusion, and a benign ovarian tumor.

Cushing’s syndrome is a set of signs and symptoms that occur due to prolonged use of corticosteroids, including hypertension and central obesity. However, this is not relevant to the patient in the question as there is no information about steroid use and the blood pressure is low.

Finally, Charcot’s triad is used in ascending cholangitis and consists of right upper quadrant pain, jaundice, and fever.

Management of ST Elevation Myocardial Infarction in Remote Locations

ST elevation myocardial infarction (STEMI) is a medical emergency that requires prompt treatment. Percutaneous coronary intervention (PCI) is the gold standard first-line treatment for STEMI, but in remote locations, the patient may need to be taken to the nearest facility for initial assessment prior to transfer for PCI. In such cases, the most appropriate management strategy should be considered to minimize time delays and optimize patient outcomes.

Administer Thrombolysis and Transfer for PCI

In cases where the transfer time to the nearest PCI facility is more than 120 minutes, fibrinolysis prior to transfer should be strongly considered. This is particularly important for patients with anterior STEMI, where time is of the essence. Aspirin, clopidogrel, and low-molecular-weight heparin should also be administered, and the patient should be transferred to a PCI-delivering facility as soon as possible.

Other Treatment Options

If PCI is not likely to be achievable within 120 minutes of when fibrinolysis could have been given, thrombolysis should be administered prior to transfer. Analgesia alone is not sufficient, and unfractionated heparin is not the optimum treatment for STEMI.

Conclusion

In remote locations, the management of STEMI requires careful consideration of the potential time delays involved in transferring the patient to a PCI-delivering facility. Administering thrombolysis prior to transfer can help minimize delays and improve patient outcomes. Aspirin, clopidogrel, and low-molecular-weight heparin should also be administered, and the patient should be transferred to a PCI-delivering facility as soon as possible.

Differentiating Types of Myocardial Infarction and Angina

When a patient presents with elevated serum cardiac enzymes and typical myocardial pain, it is likely that a myocardial infarction has occurred. If the ST elevation is limited to a few leads, it is indicative of a transmural infarction caused by the occlusion of a coronary artery. On the other hand, severely hypotensive patients who are hospitalized typically experience a more generalized subendocardial infarction.

Unstable angina, which is characterized by chest pain at rest or with minimal exertion, does not cause a rise in cardiac enzymes or ST elevation. Similarly, Prinzmetal angina, which is caused by coronary artery spasm, would not result in a marked increase in serum enzymes.

Stable angina, which is chest pain that occurs with exertion and is relieved by rest or medication, is not associated with ST elevation or a rise in cardiac enzymes.

Subendocardial infarction, which affects most ECG leads, usually occurs in the setting of shock. It is important to differentiate between the different types of myocardial infarction and angina in order to provide appropriate treatment and management.

Tips for a Hypertension-Friendly Diet

Maintaining a healthy diet is crucial for managing hypertension. Here are some tips to help you make the right food choices:

1. Load up on fruits and vegetables: Consuming a diet rich in fruits and vegetables can reduce blood pressure by 2-8 mmHg in hypertensive patients. It can also aid in weight loss, which further lowers the risk of hypertension.

2. Limit cholesterol intake: A reduction in cholesterol is essential for patients with ischaemic heart disease, and eating foods that are low in fat and cholesterol can reduce blood pressure.

3. Moderate alcohol consumption: Men should have no more than two alcoholic drinks daily to lower their risk of hypertension.

4. Eat oily fish twice a week: Eating more fish can help lower blood pressure, but having oily fish twice weekly is advised for patients with ischaemic heart disease, not hypertension alone.

5. Watch your sodium intake: Restricting dietary sodium is recommended and can lower blood pressure. A low sodium diet contains less than 2 g of sodium daily. Aim for a maximum of 7 g of dietary sodium daily.

By following these tips, you can maintain a hypertension-friendly diet and reduce your risk of complications.

Choosing the Right Statin Dose for Secondary Prevention of Coronary Events

All patients who have had a myocardial infarction should be started on an angiotensin-converting enzyme (ACE) inhibitor, a beta-blocker, a high-intensity statin, and antiplatelet therapy. Before starting a statin, liver function tests should be checked. The recommended statin dose for secondary prevention, as per NICE guidelines, is atorvastatin 80 mg od. Simvastatin 40 mg od is not the most appropriate drug of choice for secondary prevention, and atorvastatin is preferred due to its reduced incidence of myopathy. While simvastatin 80 mg od is an appropriate high-intensity statin therapy, atorvastatin is still preferred. Atorvastatin 20 mg od and 40 mg od are too low a dose to start with, and the dose may need to be increased to 80 mg in the future.

Management of Suspected Myocardial Infarction

Explanation:

When a patient presents with symptoms suggestive of myocardial infarction (MI), a troponin level should be checked. If the level is only slightly raised, it does not confirm a diagnosis of MI, but neither does it rule it out. Therefore, a repeat troponin level should be performed at least 3 hours after the first level and sent as urgent.

In an MI, cardiac enzymes are released from dead myocytes into the blood, causing enzyme levels to rise and eventually fall as they are cleared from blood. If the patient has had an MI, the repeat troponin level should either be further raised or further reduced. If the level remains roughly constant, then an alternative cause should be sought, such as pulmonary embolism, chronic kidney disease, acute kidney injury, pericarditis, heart failure, or sepsis/systemic infection.

Admission to the Coronary Care Unit (CCU) is not warranted yet. Further investigations should be performed to ascertain whether an admission is needed or whether alternative diagnoses should be explored.

Safety-netting and return to the GP should include a repeat troponin level to see if the level is stable (arguing against an MI) or is rising/falling. A repeat electrocardiogram (ECG) should be performed, and a thorough history and examination should be obtained to identify any urgent diagnoses that need to be explored before the patient is discharged.

Thrombolysis carries a risk for bleeding, so it requires a clear indication, which has not yet been obtained. Therefore, it should not be administered without proper evaluation.

The alanine transaminase (ALT) level has been used as a marker of MI in the past, but it has been since superseded as it is not specific for myocardial damage. In fact, it is now used as a component of liver function tests.

Understanding Risk Factors for Atrial Fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia that can lead to palpitations, shortness of breath, and fatigue. It is most commonly associated with alcohol consumption, chest disease, and hyperthyroidism. Other risk factors include hypertension, pericardial disease, congenital heart disease, cardiomyopathy, valvular heart disease, and coronary heart disease. AF can be classified as paroxysmal, persistent, or permanent, and may be diagnosed incidentally through an electrocardiogram (ECG) finding.

Once diagnosed, management includes investigating with a 12-lead ECG, echocardiogram, and thyroid function tests. The main objectives are rate control, rhythm control, and reducing the risk of thromboembolic disease. Rhythm control can be achieved through electrical cardioversion or drug therapy, while rate control is managed using medications such as digoxin, β-blockers, or rate-limiting calcium antagonists. Warfarin is indicated for patients with risk factors for stroke, and the risk of ischaemic stroke is calculated using the CHADS2vasc scoring system. Novel oral anticoagulants are also available as an alternative to warfarin in certain patients.

While hyperthyroidism is a recognized risk factor for AF, obesity and smoking are also associated with an increased risk of developing the condition. Pneumothorax, however, is not a recognized risk factor for AF. Understanding these risk factors can help individuals take steps to reduce their risk of developing AF and manage the condition if diagnosed.

Differentiating Cardiac Conditions: Causes and Risks

Cardiac conditions can have varying causes and risks, making it important to differentiate between them. Essential hypertension, for example, is characterized by uniform left ventricular hypertrophy and is a major risk factor for stroke. On the other hand, atrial fibrillation is a common cause of stroke but does not cause left ventricular hypertrophy and is rarer with normal atrial size. Hypertrophic obstructive cardiomyopathy, which is more common in men and often has a familial tendency, typically causes asymmetric hypertrophy of the septum and apex and can lead to arrhythmogenic or unexplained sudden cardiac death. Dilated cardiomyopathies, such as idiopathic dilated cardiomyopathy, often have no clear precipitant but cause a dilated left ventricular size, increasing the risk for a mural thrombus and an embolic risk. Finally, tuberculous pericarditis is difficult to diagnose due to non-specific features such as cough, dyspnoea, sweats, and weight loss, with typical constrictive pericarditis findings being very late features with fluid overload and severe dyspnoea. Understanding the causes and risks associated with these cardiac conditions can aid in their proper diagnosis and management.

Understanding ECG Time Measurements

When reading an electrocardiogram (ECG), it is important to understand the time measurements represented on the grid paper. The horizontal axis of the ECG represents time, with each small square measuring 1 mm in length and representing 40 milliseconds (0.04 seconds). A large square on the ECG grid has a length of 5 mm and represents 0.2 seconds. Five large squares covering a length of 25 mm on the grid represent 1 second of time. It is important to note that each small square has a length of 1 mm and equates to 40 milliseconds, not 4 seconds. Understanding these time measurements is crucial for accurately interpreting an ECG.

The patient is experiencing cardiac tamponade, which is caused by fluid in the pericardial sac compressing the heart and reducing ventricular filling. This is likely due to pericarditis caused by recent radiotherapy. Beck’s triad of low blood pressure, raised JVP, and muffled heart sounds are indicative of tamponade. Urgent pericardiocentesis is necessary to aspirate the pericardial fluid, and echocardiographic guidance is the safest method. Ibuprofen is the initial treatment for acute pericarditis without haemodynamic compromise, but in severe cases like this, it will not help. A fluid challenge with 1 litre of sodium chloride is not recommended as it may worsen the pericardial fluid. GTN spray, morphine, clopidogrel, and aspirin are useful in managing an MI, but not tamponade. LMWH is important in managing a PE, but not tamponade, and may even worsen the condition if caused by haemopericardium.

Understanding Different Types of Heart Block

Heart block is a condition where the electrical signals that control the heartbeat are disrupted, leading to an abnormal heart rhythm. There are different types of heart block, each with its own characteristic features.

First-degree heart block is characterized by a prolonged PR interval, but with a 1:1 ratio of P waves to QRS complexes. This type of heart block is usually asymptomatic and does not require treatment.

Second-degree heart block can be further divided into two types: Mobitz type 1 and Mobitz type 2. Mobitz type 1, also known as Wenckebach’s phenomenon, is characterized by a progressive lengthening of the PR interval until a QRS complex is dropped. Mobitz type 2, on the other hand, is characterized by intermittent P waves that fail to conduct to the ventricles, leading to intermittent dropped QRS complexes. This type of heart block often progresses to complete heart block.

Complete heart block, also known as third-degree heart block, occurs when there is no association between P waves and QRS complexes. The ventricular rate is often slow, reflecting a ventricular escape rhythm as the ventricles are no longer controlled by the sinoatrial node pacemaker. This type of heart block requires immediate medical attention.

Understanding the different types of heart block is important for proper diagnosis and treatment. If you experience any symptoms of heart block, such as dizziness, fainting, or chest pain, seek medical attention right away.

Differentiating Pulmonary Oedema from Other Cardiac and Respiratory Conditions

Pulmonary oedema is a condition characterized by the accumulation of fluid in the lungs due to left ventricular failure. It presents with symptoms such as shortness of breath, raised jugular venous pressure, and a third heart sound. Bi-basal crackles are also a hallmark of pulmonary oedema. However, it is important to differentiate pulmonary oedema from other cardiac and respiratory conditions that may present with similar symptoms.

Tricuspid regurgitation is another cardiac condition that may present with a raised JVP and a third heart sound. However, it is characterized by additional symptoms such as ascites, a pulsatile liver, peripheral oedema, and a pansystolic murmur. Pneumonia, on the other hand, is a respiratory infection that presents with a productive cough of yellow or green sputum and shortness of breath. Bronchial breath sounds may also be heard upon auscultation.

Pulmonary embolus is a condition that presents with chest pain, shortness of breath, and signs of an underlying deep vein thrombosis. Pericardial effusion, on the other hand, is characterized by the accumulation of fluid in the pericardial sac surrounding the heart. It may eventually lead to cardiac tamponade, which presents with hypotension, shortness of breath, and distant heart sounds. However, bi-basal crackles are not a feature of pericardial effusion.

In summary, it is important to consider the specific symptoms and characteristics of each condition in order to accurately diagnose and differentiate pulmonary oedema from other cardiac and respiratory conditions.

Treatment Options for Atrial Fibrillation in a Patient with Heart Failure

When treating a patient with atrial fibrillation (AF) and heart failure, the aim should be rate control. While bisoprolol is a good choice, it may not be suitable for a patient with chronic low blood pressure. In this case, digoxin would be the treatment of choice. Anticoagulation with a NOAC or warfarin is also necessary. Cardioversion with amiodarone should not be the first line of treatment due to the patient’s heart failure. Increasing the dose of bisoprolol may not be the best option either. Amlodipine is not effective for rate control in AF, and calcium-channel blockers should not be used in heart failure. Electrical cardioversion is not appropriate for this patient. Overall, the treatment plan should be tailored to the patient’s individual needs and medical history.

Managing Atrial Fibrillation and Heart Failure: Treatment Options

The patient in the scenario is experiencing a fast rhythm with wide complexes, which is likely ventricular tachycardia (VT). As the patient is unstable, electrical cardioversion was attempted first, as recommended by the Resuscitation Council Guideline. If cardioversion fails and the patient remains unstable, intravenous amiodarone can be used as a loading dose of 300 mg over 10-20 minutes, followed by an infusion of 900 mg/24 hours. Amiodarone is a class III anti-arrhythmic agent that prolongs the repolarization phase of the cardiac action potential by blocking potassium efflux. Side-effects associated with amiodarone include deranged thyroid and liver function tests, nausea, vomiting, bradycardia, interstitial lung disease, jaundice, and sleep disorders.

Epinephrine is used in the treatment of acute anaphylaxis and cardiopulmonary resuscitation. It acts on adrenergic receptors, causing bronchodilation and vasoconstriction. Side-effects associated with epinephrine include palpitations, arrhythmias, headache, tremor, and hypertension.

Intravenous propranolol is a non-selective β-adrenergic receptor blocker that has limited use in treating arrhythmias and thyrotoxic crisis. It is contraindicated in patients with severe hypotension, asthma, COPD, bradycardia, sick sinus rhythm, atrioventricular block, and cardiogenic shock. Side-effects associated with propranolol include insomnia, nightmares, nausea, diarrhea, bronchospasm, exacerbation of Raynaud’s, bradycardia, hypotension, and heart block.

Digoxin, a cardiac glycoside extracted from the plant genus Digitalis, can be used in the treatment of supraventricular arrhythmias and heart failure. However, it is of no use in this scenario as the patient is experiencing a broad complex tachycardia. Digoxin has a narrow therapeutic window, and even small changes in dosing can lead to toxicity. Side-effects associated with digoxin include nausea, vomiting, diarrhea, bradycardia, dizziness, yellow vision, and eosinophilia.

Diltiazem, a non-dihydropyridine calcium channel blocker, is normally used for hypertension and prophylaxis and treatment of ang

Cardiac Valve Disorders: Mitral Stenosis, Mitral Regurgitation, Aortic Regurgitation, Pulmonary Stenosis, and Primary Pulmonary Hypertension

Cardiac valve disorders are conditions that affect the proper functioning of the heart valves. Among these disorders are mitral stenosis, mitral regurgitation, aortic regurgitation, pulmonary stenosis, and primary pulmonary hypertension.

Mitral stenosis is a narrowing of the mitral valve, usually caused by rheumatic fever. Symptoms include palpitations, dyspnea, and hemoptysis. Diagnosis is aided by electrocardiogram, chest X-ray, and echocardiography. Management may be medical or surgical.

Mitral regurgitation is a systolic murmur that presents with a sustained apex beat displaced to the left and a left parasternal heave. On auscultation, there will be a soft S1, a loud S2, and a pansystolic murmur heard at the apex radiating to the left axilla.

Aortic regurgitation presents with a collapsing pulse with a wide pulse pressure. On palpation of the precordium, there will be a sustained and displaced apex beat with a soft S2 and an early diastolic murmur at the left sternal edge.

Pulmonary stenosis is associated with a normal pulse, with an ejection systolic murmur radiating to the lung fields. There may be a palpable thrill over the pulmonary area.

Primary pulmonary hypertension most commonly presents with progressive weakness and shortness of breath. There is evidence of an underlying cardiac disease, meaning the underlying pulmonary hypertension is more likely to be secondary to another disease process.

The Electrical Activity of the Heart and the ECG

The ECG (electrocardiogram) is a medical test that records the electrical activity of the heart. This activity is responsible for different parts of the ECG. The first part is the atrial depolarisation, which is represented by the P wave. This wave conducts down the bundle of His to the ventricles, causing the ventricular depolarisation. This is shown on the ECG as the QRS complex. Finally, the ventricular repolarisation is represented by the T wave.

It is important to note that atrial repolarisation is not visible on the ECG. This is because it is of lower amplitude compared to the QRS complex. the different parts of the ECG and their corresponding electrical activity can help medical professionals diagnose and treat various heart conditions.

Management of Atrial Fibrillation: Treatment Options and Considerations

Atrial fibrillation (AF) is a common cardiac arrhythmia that requires prompt management to prevent complications. The following are the treatment options and considerations for managing AF:

Investigations for Reversible Causes
Before initiating any treatment, the patient should be investigated for reversible causes of AF, such as hyperthyroidism and alcohol. Blood tests (TFTs, FBC, U and Es, LFTs, and coagulation screen) and a chest X-ray should be performed.

Medical Cardioversion
If no reversible causes are found, medical cardioversion is the most appropriate treatment for haemodynamically stable patients who present within 48 hours of the onset of AF. Amiodarone or flecainide can be used for this purpose.

DC Cardioversion
DC cardioversion is indicated for haemodynamically unstable patients, including those with shock, syncope, myocardial ischaemia, and heart failure. It is also appropriate if medical cardioversion fails.

Anticoagulation Therapy with Warfarin
Patients who remain in persistent AF for over 48 hours should have their CHA2DS2 VASc score calculated. If the score is equal to or greater than 1 for men or equal to or greater than 2 for women, anticoagulation therapy with warfarin should be initiated.

Radiofrequency Ablation
Radiofrequency ablation is not a suitable treatment for acute AF.

24-Hour Three Lead ECG Tape
Sending the patient home with a 24-hour three lead ECG tape and reviewing them in one week is not necessary as the diagnosis of AF has already been established.

In summary, the management of AF involves investigating for reversible causes, considering medical or DC cardioversion, initiating anticoagulation therapy with warfarin if necessary, and avoiding radiofrequency ablation for acute AF.

Fallot’s Tetralogy

Fallot’s tetralogy is a congenital heart defect that consists of four features: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an over-riding aorta. To diagnose this condition, doctors look for specific indicators. A step-down in oxygen saturation between the left atrium and left ventricle indicates a right to left shunt at the level of the ventricles, which is a sign of ventricular septal defect. Pulmonary stenosis is indicated by a significant gradient of 89 mmHg across the pulmonary valve, which is calculated by subtracting the right ventricular systolic pressure from the pulmonary artery systolic pressure. Right ventricular hypertrophy is diagnosed by high right ventricular pressures and a right to left shunt, as indicated by the oxygen saturations. Finally, an over-riding aorta is identified by a further step-down in oxygen saturation between the left ventricle and aorta. While this could also occur in cases of patent ductus arteriosus with right to left shunting, the presence of the other features of Fallot’s tetralogy makes an over-riding aorta the most likely cause of reduced oxygen saturation due to admixture of deoxygenated blood from the right ventricle entering the left heart circulation.