For the exam, it is important to be familiar with the statistics regarding the outcomes of outpatient and inpatient cardiac arrest in the UK.

Further Reading:

Cardiopulmonary arrest is a serious event with low survival rates. In non-traumatic cardiac arrest, only about 20% of patients who arrest as an in-patient survive to hospital discharge, while the survival rate for out-of-hospital cardiac arrest is approximately 8%. The Resus Council BLS/AED Algorithm for 2015 recommends chest compressions at a rate of 100-120 per minute with a compression depth of 5-6 cm. The ratio of chest compressions to rescue breaths is 30:2.

After a cardiac arrest, the goal of patient care is to minimize the impact of post cardiac arrest syndrome, which includes brain injury, myocardial dysfunction, the ischaemic/reperfusion response, and the underlying pathology that caused the arrest. The ABCDE approach is used for clinical assessment and general management. Intubation may be necessary if the airway cannot be maintained by simple measures or if it is immediately threatened. Controlled ventilation is aimed at maintaining oxygen saturation levels between 94-98% and normocarbia. Fluid status may be difficult to judge, but a target mean arterial pressure (MAP) between 65 and 100 mmHg is recommended. Inotropes may be administered to maintain blood pressure. Sedation should be adequate to gain control of ventilation, and short-acting sedating agents like propofol are preferred. Blood glucose levels should be maintained below 8 mmol/l. Pyrexia should be avoided, and there is some evidence for controlled mild hypothermia but no consensus on this.

Post ROSC investigations may include a chest X-ray, ECG monitoring, serial potassium and lactate measurements, and other imaging modalities like ultrasonography, echocardiography, CTPA, and CT head, depending on availability and skills in the local department. Treatment should be directed towards the underlying cause, and PCI or thrombolysis may be considered for acute coronary syndrome or suspected pulmonary embolism, respectively.

Patients who are comatose after ROSC without significant pre-arrest comorbidities should be transferred to the ICU for supportive care. Neurological outcome at 72 hours is the best prognostic indicator of outcome.

Torsades de pointes is a condition that is linked to low levels of potassium (hypokalaemia) and magnesium (hypomagnesaemia). When potassium and magnesium levels are low, it can cause the QT interval to become prolonged, which increases the risk of developing Torsades de pointes.

Further Reading:

Torsades de pointes is an irregular broad-complex tachycardia that can be life-threatening. It is a polymorphic ventricular tachycardia that can lead to sudden cardiac death. It is characterized by distinct features on the electrocardiogram (ECG).

The causes of irregular broad-complex tachycardia include atrial fibrillation with bundle branch block, atrial fibrillation with ventricular pre-excitation (in patients with Wolff-Parkinson-White syndrome), and polymorphic ventricular tachycardia such as torsades de pointes. However, sustained polymorphic ventricular tachycardia is unlikely to be present without adverse features, so it is important to seek expert help for the assessment and treatment of this condition.

Torsades de pointes can be caused by drug-induced QT prolongation, diarrhea, hypomagnesemia, hypokalemia, and congenital long QT syndrome. It may also be seen in malnourished individuals due to low potassium and/or low magnesium levels. Additionally, it can occur in individuals taking drugs that prolong the QT interval or inhibit their metabolism.

The management of torsades de pointes involves immediate action. All drugs known to prolong the QT interval should be stopped. Amiodarone should not be given for definite torsades de pointes. Electrolyte abnormalities, especially hypokalemia, should be corrected. Magnesium sulfate should be administered intravenously. If adverse features are present, immediate synchronized cardioversion should be arranged. sought, as other treatments such as overdrive pacing may be necessary to prevent relapse once the arrhythmia has been corrected. If the patient becomes pulseless, defibrillation should be attempted immediately.

In summary, torsades de pointes is a dangerous arrhythmia that requires prompt management. It is important to identify and address the underlying causes, correct electrolyte abnormalities, and seek expert help for appropriate treatment.

There is no known connection between the use of cannabis and aortic dissection. Some factors that are recognized as increasing the risk of aortic dissection include hypertension, atherosclerosis, aortic coarctation, the use of sympathomimetic drugs like cocaine, Marfan syndrome, Ehlers-Danlos syndrome, Turner’s syndrome, tertiary syphilis, and pre-existing aortic aneurysm.

In stable patients with SVT, it is recommended to first try vagal manoeuvres before resorting to drug treatment. This approach is particularly applicable to patients who do not exhibit any adverse features, as mentioned in the case above.

Further Reading:

Supraventricular tachycardia (SVT) is a type of tachyarrhythmia that originates from the atria or above the bundle of His in the heart. It includes all atrial and junctional tachycardias, although atrial fibrillation is often considered separately. SVT typically produces a narrow QRS complex tachycardia on an electrocardiogram (ECG), unless there is an underlying conduction abnormality below the atrioventricular (AV) node. Narrow complex tachycardias are considered SVTs, while some broad complex tachycardias can also be SVTs with co-existent conduction delays.

SVT can be classified into three main subtypes based on where it arises: re-entrant accessory circuits (the most common type), atrial tachycardias, and junctional tachycardias. The most common SVTs are AVNRT (AV nodal re-entry tachycardia) and AVRT (AV re-entry tachycardia), which arise from accessory circuits within the heart. AVNRT involves an accessory circuit within the AV node itself, while AVRT involves an accessory pathway between the atria and ventricles that allows additional electrical signals to trigger the AV node.

Atrial tachycardias originate from abnormal foci within the atria, except for the SA node, AV node, or accessory pathway. Junctional tachycardias arise in the AV junction. The ECG features of SVTs vary depending on the type. Atrial tachycardias may have abnormal P wave morphology, an isoelectric baseline between P waves (in atrial flutter), and inverted P waves in certain leads. AVNRT may show pseudo R waves in V1 or pseudo S waves in certain leads, with an RP interval shorter than the PR interval. AVRT (WPW) may exhibit a delta wave on a resting ECG and retrograde P waves in the ST segment, with an RP interval shorter than the PR interval. Junctional tachycardias may have retrograde P waves before, during, or after the QRS complex, with inverted P waves in certain leads and upright P waves in others.

Treatment of SVT follows the 2021 resuscitation council algorithm for tachycardia with a pulse. The algorithm provides guidelines for managing stable patients with SVT.

The majority of dissections happen in individuals between the ages of 40 and 70, with the highest occurrence observed in the age group of 50 to 65.

Further Reading:

Aortic dissection is a life-threatening condition in which blood flows through a tear in the innermost layer of the aorta, creating a false lumen. Prompt treatment is necessary as the mortality rate increases by 1-2% per hour. There are different classifications of aortic dissection, with the majority of cases being proximal. Risk factors for aortic dissection include hypertension, atherosclerosis, connective tissue disorders, family history, and certain medical procedures.

The presentation of aortic dissection typically includes sudden onset sharp chest pain, often described as tearing or ripping. Back pain and abdominal pain are also common, and the pain may radiate to the neck and arms. The clinical picture can vary depending on which aortic branches are affected, and complications such as organ ischemia, limb ischemia, stroke, myocardial infarction, and cardiac tamponade may occur. Common signs and symptoms include a blood pressure differential between limbs, pulse deficit, and a diastolic murmur.

Various investigations can be done to diagnose aortic dissection, including ECG, CXR, and CT with arterial contrast enhancement (CTA). CT is the investigation of choice due to its accuracy in diagnosis and classification. Other imaging techniques such as transoesophageal echocardiography (TOE), magnetic resonance imaging/angiography (MRI/MRA), and digital subtraction angiography (DSA) are less commonly used.

Management of aortic dissection involves pain relief, resuscitation measures, blood pressure control, and referral to a vascular or cardiothoracic team. Opioid analgesia should be given for pain relief, and resuscitation measures such as high flow oxygen and large bore IV access should be performed. Blood pressure control is crucial, and medications such as labetalol may be used to reduce systolic blood pressure. Hypotension carries a poor prognosis and may require careful fluid resuscitation. Treatment options depend on the type of dissection, with type A dissections typically requiring urgent surgery and type B dissections managed by thoracic endovascular aortic repair (TEVAR) and blood pressure control optimization.

Tricuspid regurgitation leads to a pansystolic murmur that is most pronounced in the tricuspid area during inhalation. The primary cause of tricuspid regurgitation is right ventricular failure.

Other clinical signs that may be present in tricuspid regurgitation include a raised jugular venous pressure (JVP) and giant C-V waves. Additionally, features of increased right atrial pressure, such as ascites and dependent edema, may be observed. Pulsatile hepatomegaly and a thrill at the left sternal edge are also possible indicators. Reverse splitting of the second heart sound, due to early closure of the pulmonary valve, and a third heart sound, caused by rapid right ventricular filling, may be heard as well.

Aortic regurgitation, on the other hand, produces an early diastolic murmur that is most audible at the lower left sternal edge when the patient is sitting forward and exhaling.

In the case of mitral stenosis, a rumbling mid-diastolic murmur is best heard at the apex while the patient is in the left lateral position and exhaling, using the bell of the stethoscope.

Atrial myxomas are benign tumors that can develop in the heart. Most commonly found on the left side, they may obstruct the mitral valve, resulting in a mid-diastolic murmur similar to that of mitral stenosis.

Lastly, left anterior descending artery stenosis can cause an early diastolic murmur, also known as Dock’s murmur. This murmur is similar to that of aortic regurgitation and is best heard at the left 2nd or 3rd intercostal space.

The first heart sound (S1) is created by vibrations produced when the mitral and tricuspid valves close. It occurs at the end of diastole and the start of ventricular systole, coming before the upstroke of the carotid pulsation.

A sample of the normal heart sounds can be listened to here (courtesy of Littman stethoscopes).

A loud S1 can be associated with the following conditions:
– Increased transvalvular gradient (e.g. mitral stenosis, tricuspid stenosis)
– Increased force of ventricular contraction (e.g. tachycardia, hyperdynamic states like fever and thyrotoxicosis)
– Shortened PR interval (e.g. Wolff-Parkinson-White syndrome)
– Mitral valve prolapse
– Thin individuals

A soft S1 can be associated with the following conditions:
– Inappropriate apposition of the AV valves (e.g. mitral regurgitation, tricuspid regurgitation)
– Prolonged PR interval (e.g. heart block, digoxin toxicity)
– Decreased force of ventricular contraction (e.g. myocarditis, myocardial infarction)
– Increased distance from the heart (e.g. obesity, emphysema, pericardial effusion)

A split S1 can be associated with the following conditions:
– Right bundle branch block
– LV pacing
– Ebstein anomaly

Anaphylaxis, also known as anaphylactic shock, is characterized by certain symptoms similar to other types of shock. These symptoms include low blood pressure (hypotension), rapid heart rate (tachycardia), irregular heart rhythm (arrhythmia), changes in the electrocardiogram (ECG) indicating reduced blood flow to the heart (myocardial ischemia), such as ST elevation, and in severe cases, cardiac arrest.

Further Reading:

Anaphylaxis is a severe and life-threatening hypersensitivity reaction that can have sudden onset and progression. It is characterized by skin or mucosal changes and can lead to life-threatening airway, breathing, or circulatory problems. Anaphylaxis can be allergic or non-allergic in nature.

In allergic anaphylaxis, there is an immediate hypersensitivity reaction where an antigen stimulates the production of IgE antibodies. These antibodies bind to mast cells and basophils. Upon re-exposure to the antigen, the IgE-covered cells release histamine and other inflammatory mediators, causing smooth muscle contraction and vasodilation.

Non-allergic anaphylaxis occurs when mast cells degrade due to a non-immune mediator. The clinical outcome is the same as in allergic anaphylaxis.

The management of anaphylaxis is the same regardless of the cause. Adrenaline is the most important drug and should be administered as soon as possible. The recommended doses for adrenaline vary based on age. Other treatments include high flow oxygen and an IV fluid challenge. Corticosteroids and chlorpheniramine are no longer recommended, while non-sedating antihistamines may be considered as third-line treatment after initial stabilization of airway, breathing, and circulation.

Common causes of anaphylaxis include food (such as nuts, which is the most common cause in children), drugs, and venom (such as wasp stings). Sometimes it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis.

The Resuscitation Council (UK) provides guidelines for the management of anaphylaxis, including a visual algorithm that outlines the recommended steps for treatment.
https://www.resus.org.uk/sites/default/files/2021-05/Emergency%20Treatment%20of%20Anaphylaxis%20May%202021_0.pdf

Dressler’s syndrome is a form of pericarditis that occurs within 2 to 10 weeks following a heart attack or cardiac surgery. It is distinguished by intense chest pain that is usually alleviated by assuming an upright position. Additionally, individuals may experience a mild fever, a pericardial rub, pulsus paradoxus, and indications of right ventricular failure.

Adrenaline should be administered promptly once access to the circulatory system has been established in cases of non-shockable cardiac arrests such as PEA or asystole. The recommended dose is 1 mg, which can be given either as 10 mL of a 1:10,000 solution or as 1 mL of a 1:1000 solution through the intravenous (IV) or intraosseous (IO) routes.

In cases of shockable cardiac arrests like ventricular fibrillation (Vf) or pulseless ventricular tachycardia (pVT), adrenaline should be administered after the third shock has been delivered and chest compressions have been resumed. The same dose of 1 mg can be given using the same concentration options as mentioned earlier.

Subsequently, adrenaline should be administered every 3-5 minutes, alternating with chest compressions, without interrupting the compressions. The alpha-adrenergic effects of adrenaline cause constriction of blood vessels throughout the body, leading to increased pressures in the coronary and cerebral circulation.

The beta-adrenergic effects of adrenaline have positive effects on the heart, increasing its contractility (inotropic) and heart rate (chronotropic), which may also enhance blood flow to the coronary and cerebral arteries. However, it is important to note that these benefits may be counteracted by increased oxygen consumption by the heart, the potential for abnormal heart rhythms, temporary decrease in oxygen levels due to abnormal blood flow in the lungs, impaired microcirculation, and increased dysfunction of the heart after the cardiac arrest.

While there is no evidence supporting the long-term benefits of adrenaline use in cardiac arrest cases, some studies have shown improved short-term survival rates, which justifies its continued use.

The clinical symptoms of mitral stenosis include shortness of breath, which tends to worsen during exercise and when lying flat. Tiredness, palpitations, ankle swelling, cough, and haemoptysis are also common symptoms. Chest discomfort is rarely reported.

The clinical signs of mitral stenosis can include a malar flush, an irregular pulse if atrial fibrillation is present, a tapping apex beat that can be felt as the first heart sound, and a left parasternal heave if there is pulmonary hypertension. The first heart sound is often loud, and a mid-diastolic murmur can be heard.

The mid-diastolic murmur of mitral stenosis is a rumbling sound that is best heard at the apex, in the left lateral position during expiration, using the bell of the stethoscope.

Mitral stenosis is typically caused by rheumatic heart disease, and it is more common in females, with about two-thirds of patients being female.

Aortic stenosis leads to the presence of a murmur during the ejection phase of the cardiac cycle. This murmur is most audible at the right second intercostal space and can be heard extending into the right neck.

Mitral regurgitation, on the other hand, produces a high-pitched murmur that occurs throughout the entire systolic phase of the cardiac cycle. This murmur is best heard at the apex of the heart and can be heard radiating into the axilla.

Tricuspid regurgitation is characterized by a blowing murmur that occurs throughout the entire systolic phase of the cardiac cycle. This murmur is most clearly heard at the lower left sternal edge.

Ventricular septal defect results in a harsh murmur that occurs throughout the entire systolic phase of the cardiac cycle. This murmur is best heard at the third or fourth left intercostal space and can be heard radiating throughout the praecordium.

Aortopulmonary shunts are an extremely rare cause of a murmur that occurs throughout the entire systolic phase of the cardiac cycle.

For patients suspected of having acute coronary syndromes (ACS), it is recommended that they receive 300 mg of aspirin and pain relief in the form of glyceryl trinitrate (GTN) with the option of intravenous opioids such as morphine. However, if the patient is pain-free after taking GTN, there is no need to administer morphine. The next steps in medical management or intervention will be determined once the diagnosis is confirmed.

Further Reading:

Acute Coronary Syndromes (ACS) is a term used to describe a group of conditions that involve the sudden reduction or blockage of blood flow to the heart. This can lead to a heart attack or unstable angina. ACS includes ST segment elevation myocardial infarction (STEMI), non-ST segment elevation myocardial infarction (NSTEMI), and unstable angina (UA).

The development of ACS is usually seen in patients who already have underlying coronary heart disease. This disease is characterized by the buildup of fatty plaques in the walls of the coronary arteries, which can gradually narrow the arteries and reduce blood flow to the heart. This can cause chest pain, known as angina, during physical exertion. In some cases, the fatty plaques can rupture, leading to a complete blockage of the artery and a heart attack.

There are both non modifiable and modifiable risk factors for ACS. non modifiable risk factors include increasing age, male gender, and family history. Modifiable risk factors include smoking, diabetes mellitus, hypertension, hypercholesterolemia, and obesity.

The symptoms of ACS typically include chest pain, which is often described as a heavy or constricting sensation in the central or left side of the chest. The pain may also radiate to the jaw or left arm. Other symptoms can include shortness of breath, sweating, and nausea/vomiting. However, it’s important to note that some patients, especially diabetics or the elderly, may not experience chest pain.

The diagnosis of ACS is typically made based on the patient’s history, electrocardiogram (ECG), and blood tests for cardiac enzymes, specifically troponin. The ECG can show changes consistent with a heart attack, such as ST segment elevation or depression, T wave inversion, or the presence of a new left bundle branch block. Elevated troponin levels confirm the diagnosis of a heart attack.

The management of ACS depends on the specific condition and the patient’s risk factors. For STEMI, immediate coronary reperfusion therapy, either through primary percutaneous coronary intervention (PCI) or fibrinolysis, is recommended. In addition to aspirin, a second antiplatelet agent is usually given. For NSTEMI or unstable angina, the treatment approach may involve reperfusion therapy or medical management, depending on the patient’s risk of future cardiovascular events.

Atropine acts as an antagonist to the parasympathetic neurotransmitter acetylcholine at muscarinic receptors. This means that it blocks the effects of the vagus nerve on both the SA node and the AV node, resulting in increased sinus automaticity and improved AV node conduction.

The side effects of atropine are dependent on the dosage and may include dry mouth, nausea and vomiting, blurred vision, urinary retention, and tachyarrhythmias. Elderly patients may also experience acute confusion and hallucinations.

Atropine is recommended for use in cases of sinus, atrial, or nodal bradycardia or AV block when the patient’s hemodynamic condition is unstable due to the bradycardia. According to the ALS bradycardia algorithm, an initial dose of 500 mcg IV is suggested if any adverse features such as shock, syncope, myocardial ischemia, or heart failure are present. If this initial dose is unsuccessful, additional 500 mcg doses can be administered at 3-5 minute intervals, with a maximum dose of 3 mg. It is important to avoid doses exceeding 3 mg as they can paradoxically slow the heart rate.

Asystole during cardiac arrest is typically caused by primary myocardial pathology rather than excessive vagal tone. Therefore, there is no evidence supporting the routine use of atropine in the treatment of asystole or PEA. Consequently, atropine is no longer included in the non-shockable part of the ALS algorithm.

Aside from its use in cardiac conditions, atropine also has other applications. It can be used topically in the eyes as a cycloplegic and mydriatic, to reduce secretions during anesthesia, and in the treatment of organophosphate poisoning.

Atropine is a medication that slows down the movement of the digestive system and is not recommended for use in individuals with intestinal blockage. It works by blocking the effects of a neurotransmitter called acetylcholine, which is responsible for promoting gastrointestinal motility and the emptying of the stomach. Therefore, atropine should not be given to patients with gastrointestinal obstruction as it can further hinder the movement of the intestines.

Further Reading:

Types of Heart Block:

1. Atrioventricular (AV) Blocks:
– Disrupt electrical conduction between the atria and ventricles at the AV node.
– Three degrees of AV block: first degree, second degree (type 1 and type 2), and third degree (complete) AV block.

– First degree AV block: PR interval > 0.2 seconds.
– Second degree AV block:
– Type 1 (Mobitz I, Wenckebach): progressive prolongation of the PR interval until a dropped beat occurs.
– Type 2 (Mobitz II): PR interval is constant, but the P wave is often not followed by a QRS complex.
– Third degree (complete) AV block: no association between the P waves and QRS complexes.

Features of complete heart block: syncope, heart failure, regular bradycardia (30-50 bpm), wide pulse pressure, JVP (jugular venous pressure) cannon waves in neck, variable intensity of S1.

2. Bundle Branch Blocks:
– Electrical conduction travels from the bundle of His to the left and right bundle branches.
– Diagnosed when the duration of the QRS complex on the ECG exceeds 120 ms.

– Right bundle branch block (RBBB).
– Left bundle branch block (LBBB).
– Left anterior fascicular block (LAFB).
– Left posterior fascicular block (LPFB).
– Bifascicular block.
– Trifascicular block.

ECG features of bundle branch blocks:
– RBBB: QRS duration > 120 ms, RSR’ pattern in V1-3 (M-shaped QRS complex), wide S wave in lateral leads (I, aVL, V5-6).
– LBBB: QRS duration > 120 ms, dominant S wave in V1, broad, notched (‘M’-shaped) R wave in V6, broad monophasic R wave in lateral leads (I, aVL, V5-6), absence of Q waves in lateral leads, prolonged R wave peak time > 60 ms in leads V5-6.

WiLLiaM MaRROW is a useful mnemonic for remembering the morphology of the QRS in leads V1 and V6 for LBBB.

Orthostatic hypotension is a condition where patients feel lightheaded and may experience tunnel vision when they stand up from a lying down position. These symptoms are often worse in the morning. The patient’s history of recurrent episodes after being in a supine position for a long time strongly suggests orthostatic hypotension. There are no signs of epilepsy, such as deja-vu or jambs vu prodrome, tongue biting, loss of bladder or bowel control, or postictal confusion. The normal ECG and consistent timing of symptoms make postural orthostatic tachycardia syndrome (PAF) less likely. There are no neurological deficits to suggest a transient ischemic attack (TIA). The prodromal symptoms, such as tunnel vision and lightheadedness, align more with orthostatic hypotension rather than vasovagal syncope, which typically occurs after long periods of standing and is characterized by feeling hot and sweaty. Although carotid sinus syndrome could be considered as a differential diagnosis, as the patient’s head turning on getting out of bed may trigger symptoms, it is not one of the options.

Further Reading:

Blackouts, also known as syncope, are defined as a spontaneous transient loss of consciousness with complete recovery. They are most commonly caused by transient inadequate cerebral blood flow, although epileptic seizures can also result in blackouts. There are several different causes of blackouts, including neurally-mediated reflex syncope (such as vasovagal syncope or fainting), orthostatic hypotension (a drop in blood pressure upon standing), cardiovascular abnormalities, and epilepsy.

When evaluating a patient with blackouts, several key investigations should be performed. These include an electrocardiogram (ECG), heart auscultation, neurological examination, vital signs assessment, lying and standing blood pressure measurements, and blood tests such as a full blood count and glucose level. Additional investigations may be necessary depending on the suspected cause, such as ultrasound or CT scans for aortic dissection or other abdominal and thoracic pathology, chest X-ray for heart failure or pneumothorax, and CT pulmonary angiography for pulmonary embolism.

During the assessment, it is important to screen for red flags and signs of any underlying serious life-threatening condition. Red flags for blackouts include ECG abnormalities, clinical signs of heart failure, a heart murmur, blackouts occurring during exertion, a family history of sudden cardiac death at a young age, an inherited cardiac condition, new or unexplained breathlessness, and blackouts in individuals over the age of 65 without a prodrome. These red flags indicate the need for urgent assessment by an appropriate specialist.

There are several serious conditions that may be suggested by certain features. For example, myocardial infarction or ischemia may be indicated by a history of coronary artery disease, preceding chest pain, and ECG signs such as ST elevation or arrhythmia. Pulmonary embolism may be suggested by dizziness, acute shortness of breath, pleuritic chest pain, and risk factors for venous thromboembolism. Aortic dissection may be indicated by chest and back pain, abnormal ECG findings, and signs of cardiac tamponade include low systolic blood pressure, elevated jugular venous pressure, and muffled heart sounds. Other conditions that may cause blackouts include severe hypoglycemia, Addisonian crisis, and electrolyte abnormalities.

Atropine should not be given to patients with certain conditions, including heart transplant, angle-closure glaucoma, gastrointestinal motility disorders, myasthenia gravis, severe ulcerative colitis, toxic megacolon, bladder outflow obstruction, and urinary retention. In heart transplant patients, atropine will not have the desired effect as the denervated hearts do not respond to vagal blockade. Giving atropine in these patients may even lead to paradoxical sinus arrest or high-grade AV block.

Further Reading:

Causes of Bradycardia:
– Physiological: Athletes, sleeping
– Cardiac conduction dysfunction: Atrioventricular block, sinus node disease
– Vasovagal & autonomic mediated: Vasovagal episodes, carotid sinus hypersensitivity
– Hypothermia
– Metabolic & electrolyte disturbances: Hypothyroidism, hyperkalaemia, hypermagnesemia
– Drugs: Beta-blockers, calcium channel blockers, digoxin, amiodarone
– Head injury: Cushing’s response
– Infections: Endocarditis
– Other: Sarcoidosis, amyloidosis

Presenting symptoms of Bradycardia:
– Presyncope (dizziness, lightheadedness)
– Syncope
– Breathlessness
– Weakness
– Chest pain
– Nausea

Management of Bradycardia:
– Assess and monitor for adverse features (shock, syncope, myocardial ischaemia, heart failure)
– Treat reversible causes of bradycardia
– Pharmacological treatment: Atropine is first-line, adrenaline and isoprenaline are second-line
– Transcutaneous pacing if atropine is ineffective
– Other drugs that may be used: Aminophylline, dopamine, glucagon, glycopyrrolate

Bradycardia Algorithm:
– Follow the algorithm for management of bradycardia, which includes assessing and monitoring for adverse features, treating reversible causes, and using appropriate medications or pacing as needed.
https://acls-algorithms.com/wp-content/uploads/2020/12/Website-Bradycardia-Algorithm-Diagram.pdf

Aortic dissection is a condition that occurs when the middle layer of the aorta, known as the tunica media, becomes weakened. This weakening leads to the development of cases of aortic dissection.

Further Reading:

Aortic dissection is a life-threatening condition in which blood flows through a tear in the innermost layer of the aorta, creating a false lumen. Prompt treatment is necessary as the mortality rate increases by 1-2% per hour. There are different classifications of aortic dissection, with the majority of cases being proximal. Risk factors for aortic dissection include hypertension, atherosclerosis, connective tissue disorders, family history, and certain medical procedures.

The presentation of aortic dissection typically includes sudden onset sharp chest pain, often described as tearing or ripping. Back pain and abdominal pain are also common, and the pain may radiate to the neck and arms. The clinical picture can vary depending on which aortic branches are affected, and complications such as organ ischemia, limb ischemia, stroke, myocardial infarction, and cardiac tamponade may occur. Common signs and symptoms include a blood pressure differential between limbs, pulse deficit, and a diastolic murmur.

Various investigations can be done to diagnose aortic dissection, including ECG, CXR, and CT with arterial contrast enhancement (CTA). CT is the investigation of choice due to its accuracy in diagnosis and classification. Other imaging techniques such as transoesophageal echocardiography (TOE), magnetic resonance imaging/angiography (MRI/MRA), and digital subtraction angiography (DSA) are less commonly used.

Management of aortic dissection involves pain relief, resuscitation measures, blood pressure control, and referral to a vascular or cardiothoracic team. Opioid analgesia should be given for pain relief, and resuscitation measures such as high flow oxygen and large bore IV access should be performed. Blood pressure control is crucial, and medications such as labetalol may be used to reduce systolic blood pressure. Hypotension carries a poor prognosis and may require careful fluid resuscitation. Treatment options depend on the type of dissection, with type A dissections typically requiring urgent surgery and type B dissections managed by thoracic endovascular aortic repair (TEVAR) and blood pressure control optimization.

Amiodarone is a medication that is recommended to be administered after the third shock in a shockable cardiac arrest (Vf/pVT) while chest compressions are being performed. The prescribed dose is 300 mg, given as an intravenous bolus that is diluted in 5% dextrose to a volume of 20 mL. It is important to note that amiodarone is not suitable for treating PEA or asystole.

In cases where VF/pVT persists after five defibrillation attempts, an additional dose of 150 mg of amiodarone should be given. However, if amiodarone is not available, lidocaine can be used as an alternative. The recommended dose of lidocaine is 1 mg/kg. It is crucial to avoid administering lidocaine if amiodarone has already been given.

Amiodarone is classified as a membrane-stabilizing antiarrhythmic drug. It works by prolonging the duration of the action potential and the refractory period in both the atrial and ventricular myocardium. This medication also slows down atrioventricular conduction and has a similar effect on accessory pathways.

Additionally, amiodarone has a mild negative inotropic action, meaning it weakens the force of heart contractions. It also causes peripheral vasodilation through non-competitive alpha-blocking effects.

It is important to note that while there is no evidence of long-term benefits from using amiodarone, it may improve short-term survival rates, which justifies its continued use.

The timing of the initial rise, peak, and return to normality of various cardiac enzymes can serve as a helpful guide. Creatine kinase, the main cardiac isoenzyme, typically experiences an initial rise within 4-8 hours, reaches its peak at 18 hours, and returns to normal within 2-3 days. Myoglobin, which lacks specificity due to its association with skeletal muscle damage, shows an initial rise within 1-4 hours, peaks at 6-7 hours, and returns to normal within 24 hours. Troponin I, known for its sensitivity and specificity, exhibits an initial rise within 3-12 hours, reaches its peak at 24 hours, and returns to normal within 3-10 days. HFABP, or heart fatty acid binding protein, experiences an initial rise within 1.5 hours, peaks at 5-10 hours, and returns to normal within 24 hours. Lastly, LDH, predominantly found in cardiac muscle, shows an initial rise at 10 hours, peaks at 24-48 hours, and returns to normal within 14 days.