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.

When managing newly diagnosed atrial fibrillation, a rate control strategy is often used. In this approach, beta blockers are typically the first line of treatment. However, sotalol is not recommended, and instead, other beta blockers like atenolol, acebutolol, metoprolol, nadolol, oxprenolol, and propranolol are preferred. Among these options, atenolol is commonly chosen in NHS trusts due to its cost-effectiveness.

For patients with signs of hemodynamic instability or adverse features, rhythm control (cardioversion) may be considered if they present within 48 hours of likely onset. However, in the case of this patient, their symptoms started a week ago, and there are no indications of hemodynamic instability or adverse features.

Digoxin monotherapy is typically reserved for individuals who have limited physical activity or are unable to take other first-line rate control medications due to other health conditions or contraindications.

Further Reading:

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting around 5% of patients over the age of 70-75 years and 10% of patients aged 80-85 years. While AF can cause palpitations and inefficient cardiac function, the most important aspect of managing patients with AF is reducing the increased risk of stroke.

AF can be classified as first detected episode, paroxysmal, persistent, or permanent. First detected episode refers to the initial occurrence of AF, regardless of symptoms or duration. Paroxysmal AF occurs when a patient has 2 or more self-terminating episodes lasting less than 7 days. Persistent AF refers to episodes lasting more than 7 days that do not self-terminate. Permanent AF is continuous atrial fibrillation that cannot be cardioverted or if attempts to do so are deemed inappropriate. The treatment goals for permanent AF are rate control and anticoagulation if appropriate.

Symptoms of AF include palpitations, dyspnea, and chest pain. The most common sign is an irregularly irregular pulse. An electrocardiogram (ECG) is essential for diagnosing AF, as other conditions can also cause an irregular pulse.

Managing patients with AF involves two key parts: rate/rhythm control and reducing stroke risk. Rate control involves slowing down the irregular pulse to avoid negative effects on cardiac function. This is typically achieved using beta-blockers or rate-limiting calcium channel blockers. If one drug is not effective, combination therapy may be used. Rhythm control aims to restore and maintain normal sinus rhythm through pharmacological or electrical cardioversion. However, the majority of patients are managed with a rate control strategy.

Reducing stroke risk in patients with AF is crucial. Risk stratifying tools, such as the CHA2DS2-VASc score, are used to determine the most appropriate anticoagulation strategy. Anticoagulation is recommended for patients with a score of 2 or more. Clinicians can choose between warfarin and novel oral anticoagulants (NOACs) for anticoagulation.

Before starting anticoagulation, the patient’s bleeding risk should be assessed using tools like the HAS-BLED score or the ORBIT tool. These tools evaluate factors such as hypertension, abnormal renal or liver function, history of bleeding, age, and use of drugs that predispose to bleeding.

This patient is likely experiencing an acute coronary syndrome, possibly a non-ST-elevation myocardial infarction (NSTEMI) or unstable angina. The troponin test will help confirm the diagnosis. The patient’s ECG showed ST depression in the inferior leads, but this normalized after treatment with GTN and morphine, ruling out a ST-elevation myocardial infarction (STEMI).

Immediate pain relief should be provided. GTN (sublingual or buccal) can be used, but intravenous opioids like morphine should be considered, especially if a heart attack is suspected.

Aspirin should be given to all patients with unstable angina or NSTEMI as soon as possible and continued indefinitely, unless there are contraindications like bleeding risk or aspirin hypersensitivity. A loading dose of 300 mg should be administered right after presentation.

Fondaparinux should be given to patients without a high bleeding risk, unless coronary angiography is planned within 24 hours of admission. Unfractionated heparin can be an alternative to fondaparinux for patients who will undergo coronary angiography within 24 hours. For patients with significant renal impairment, unfractionated heparin can also be considered, with dose adjustment based on clotting function monitoring.

Routine administration of oxygen is no longer recommended, but oxygen saturation should be monitored using pulse oximetry as soon as possible, preferably before hospital admission. Supplemental oxygen should only be offered to individuals with oxygen saturation (SpO2) below 94% who are not at risk of hypercapnic respiratory failure, aiming for a SpO2 of 94-98%. For individuals with chronic obstructive pulmonary disease at risk of hypercapnic respiratory failure, a target SpO2 of 88-92% should be achieved until blood gas analysis is available.

Bivalirudin, a specific and reversible direct thrombin inhibitor (DTI), is recommended by NICE as a possible treatment for adults with STEMI undergoing percutaneous coronary intervention.

For more information, refer to the NICE guidelines on the assessment and diagnosis of chest pain of recent onset.

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.

Lown-Ganong-Levine (LGL) syndrome is a condition that affects the electrical conducting system of the heart. It is classified as a pre-excitation syndrome, similar to the more well-known Wolff-Parkinson-White (WPW) syndrome. However, unlike WPW syndrome, LGL syndrome does not involve an accessory pathway for conduction. Instead, it is believed that there may be accessory fibers present that bypass all or part of the atrioventricular node.

When looking at an electrocardiogram (ECG) of a patient with LGL syndrome in sinus rhythm, there are several characteristic features to observe. The PR interval, which represents the time it takes for the electrical signal to travel from the atria to the ventricles, is typically shortened and measures less than 120 milliseconds. The QRS duration, which represents the time it takes for the ventricles to contract, is normal. The P wave, which represents the electrical activity of the atria, may be normal or inverted. However, what distinguishes LGL syndrome from other pre-excitation syndromes is the absence of a delta wave, which is a slurring of the initial rise in the QRS complex.

It is important to note that LGL syndrome predisposes individuals to paroxysmal supraventricular tachycardia (SVT), a rapid heart rhythm that originates above the ventricles. However, it does not increase the risk of developing atrial fibrillation or flutter, which are other types of abnormal heart rhythms.

Amiodarone is recommended to be administered after the third shock in a shockable cardiac arrest (Vf/pVT) while performing chest compressions. The prescribed dose is 300 mg, which should be given as an intravenous bolus. To ensure proper administration, the medication should be diluted in 20 mL of 5% dextrose solution.

In cases where VF/pVT continues after five defibrillation attempts, an additional dose of 150 mg of Amiodarone should be administered. It is important to note that Amiodarone is not suitable for treating PEA or asystole, and its use is specifically indicated for shockable cardiac arrest situations.

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.

Tenecteplase is a medication known as a tissue plasminogen activator (tPA). Its main mechanism of action involves binding specifically to fibrin and converting plasminogen into plasmin. This process leads to the breakdown of the fibrin matrix and promotes reperfusion at the affected site. Among the options provided, Tenecteplase is the sole drug that primarily acts by facilitating reperfusion.

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

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.

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.

Narrow QRS complex tachycardia is a term used to describe a fast heart rhythm with a pulse rate over 100 bpm and a QRS duration shorter than 120 ms.

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.

Beta blockers are the primary treatment for long QT syndrome (LQTS). This patient probably has an undiagnosed congenital LQTS because there is no obvious cause. If there is a known cause of LQTS that can be removed, removing it may be the only necessary treatment. However, in all other cases, beta blockers are usually needed to prevent ventricular arrhythmias. Ventricular arrhythmias happen because of increased adrenergic activity. Beta blockers reduce the effects of adrenergic stimulation.

Further Reading:

Long QT syndrome (LQTS) is a condition characterized by a prolonged QT interval on an electrocardiogram (ECG), which represents abnormal repolarization of the heart. LQTS can be either acquired or congenital. Congenital LQTS is typically caused by gene abnormalities that affect ion channels responsible for potassium or sodium flow in the heart. There are 15 identified genes associated with congenital LQTS, with three genes accounting for the majority of cases. Acquired LQTS can be caused by various factors such as certain medications, electrolyte imbalances, hypothermia, hypothyroidism, and bradycardia from other causes.

The normal QTc values, which represent the corrected QT interval for heart rate, are typically less than 450 ms for men and less than 460ms for women. Prolonged QTc intervals are considered to be greater than these values. It is important to be aware of drugs that can cause QT prolongation, as this can lead to potentially fatal arrhythmias. Some commonly used drugs that can cause QT prolongation include antimicrobials, antiarrhythmics, antipsychotics, antidepressants, antiemetics, and others.

Management of long QT syndrome involves addressing any underlying causes and using beta blockers. In some cases, an implantable cardiac defibrillator (ICD) may be recommended for patients who have experienced recurrent arrhythmic syncope, documented torsades de pointes, previous ventricular tachyarrhythmias or torsades de pointes, previous cardiac arrest, or persistent syncope. Permanent pacing may be used in patients with bradycardia or atrioventricular nodal block and prolonged QT. Mexiletine is a treatment option for those with LQT3. Cervicothoracic sympathetic denervation may be considered in patients with recurrent syncope despite beta-blockade or in those who are not ideal candidates for an ICD. The specific treatment options for LQTS depend on the type and severity of the condition.

Post myocardial infarction ventricular septal defect (VSD) is a rare but serious complication that occurs when the cardiac wall ruptures. It typically develops 2-3 days after a heart attack, and if left untreated, 85% of patients will die within two months. The murmur associated with VSD is a continuous sound throughout systole, and it is loudest at the lower left sternal edge. A palpable vibration, known as a thrill, is often felt along with the murmur.

Dressler’s syndrome, on the other hand, is a type of pericarditis that occurs 2-10 weeks after a heart attack or cardiac surgery. It is characterized by sharp chest pain that is relieved by sitting forwards. Other signs of Dressler’s syndrome include a rubbing sound heard when listening to the heart, pulsus paradoxus (an abnormal drop in blood pressure during inspiration), and signs of right ventricular failure.

Mitral regurgitation also causes a continuous murmur throughout systole, but it is best heard at the apex of the heart and may radiate to the axilla (armpit).

Tricuspid stenosis, on the other hand, causes an early diastolic murmur that is best heard at the lower left sternal edge during inspiration.

Lastly, mitral stenosis causes a rumbling mid-diastolic murmur that is best heard at the apex of the heart. To listen for this murmur, the patient should be in the left lateral position, and the stethoscope bell should be used during expiration.

In order to gain a comprehensive understanding of AF management, it is crucial to familiarize oneself with the terminology used to describe its various subtypes. These terms help categorize different episodes of AF based on their characteristics and outcomes.

Acute AF refers to any episode that occurs within the previous 48 hours. It can manifest with or without symptoms and may or may not recur. On the other hand, paroxysmal AF describes episodes that spontaneously end within 7 days, typically within 48 hours. While these episodes are often recurrent, they can progress into a sustained form of AF.

Recurrent AF is defined as experiencing two or more episodes of AF. If the episodes self-terminate, they are classified as paroxysmal AF. However, if the episodes do not self-terminate, they are categorized as persistent AF. Persistent AF lasts longer than 7 days or has occurred after a previous cardioversion. To terminate persistent AF, electrical or pharmacological intervention is required. In some cases, persistent AF can progress into permanent AF.

Permanent AF, also known as Accepted AF, refers to episodes that cannot be successfully terminated, have relapsed after termination, or where cardioversion is not pursued. This subtype signifies a more chronic and ongoing form of AF.

By understanding and utilizing these terms, healthcare professionals can effectively communicate and manage the different subtypes of AF.

Adrenaline and isoprenaline are considered as second-line medications for the treatment of bradycardia. If atropine fails to improve the condition, transcutaneous pacing is recommended. However, if pacing is not available, the administration of second-line drugs becomes necessary. Adrenaline is typically given intravenously at a dosage of 2-10 mcg/minute, while isoprenaline is given at a dosage of 5 mcg/minute. It is important to note that glucagon is not mentioned as a treatment option for this patient’s bradycardia, as the cause of the condition is not specified as a beta-blocker overdose.

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

Mitral stenosis is a condition characterized by a narrowing of the mitral valve, which can lead to various symptoms. One common symptom is a mid-late diastolic murmur, which can be heard during a physical examination. This murmur may also be described as mid-diastolic, late-diastolic, or mid-late diastolic. Additionally, patients with chronic mitral stenosis may not experience any symptoms, and the murmur may only be detected incidentally.

A significant risk associated with mitral stenosis is the development of atrial fibrillation (AF). When AF occurs in patients with mitral stenosis, it can trigger acute pulmonary edema. This happens because the left atrium, which is responsible for pumping blood across the narrowed mitral valve into the left ventricle, needs to generate higher pressure. However, when AF occurs, the atrial contraction becomes inefficient, leading to impaired emptying of the left atrium. This, in turn, causes increased back pressure in the pulmonary circulation.

The elevated pressure in the left atrium and pulmonary circulation can result in the rupture of bronchial veins, leading to the production of pink frothy sputum. This symptom is often observed in patients with mitral stenosis who develop acute pulmonary edema.

Further Reading:

Mitral Stenosis:
– Causes: Rheumatic fever, Mucopolysaccharidoses, Carcinoid, Endocardial fibroelastosis
– Features: Mid-late diastolic murmur, loud S1, opening snap, low volume pulse, malar flush, atrial fibrillation, signs of pulmonary edema, tapping apex beat
– Features of severe mitral stenosis: Length of murmur increases, opening snap becomes closer to S2
– Investigation findings: CXR may show left atrial enlargement, echocardiography may show reduced cross-sectional area of the mitral valve

Mitral Regurgitation:
– Causes: Mitral valve prolapse, Myxomatous degeneration, Ischemic heart disease, Rheumatic fever, Connective tissue disorders, Endocarditis, Dilated cardiomyopathy
– Features: pansystolic murmur radiating to left axilla, soft S1, S3, laterally displaced apex beat with heave
– Signs of acute MR: Decompensated congestive heart failure symptoms
– Signs of chronic MR: Leg edema, fatigue, arrhythmia (atrial fibrillation)
– Investigation findings: Doppler echocardiography to detect regurgitant flow and pulmonary hypertension, ECG may show signs of LA enlargement and LV hypertrophy, CXR may show LA and LV enlargement in chronic MR and pulmonary edema in acute MR.

In order to gain a comprehensive understanding of AF management, it is crucial to familiarize oneself with the terminology used to describe its various subtypes. These terms help categorize different episodes of AF based on their characteristics and outcomes.

Acute AF refers to any episode that occurs within the previous 48 hours. It can manifest with or without symptoms and may or may not recur. On the other hand, paroxysmal AF describes episodes that spontaneously end within 7 days, typically within 48 hours. While these episodes are often recurrent, they can progress into a sustained form of AF.

Recurrent AF is defined as experiencing two or more episodes of AF. If the episodes self-terminate, they are classified as paroxysmal AF. However, if the episodes do not self-terminate, they are categorized as persistent AF. Persistent AF lasts longer than 7 days or has occurred after a previous cardioversion. To terminate persistent AF, electrical or pharmacological intervention is required. In some cases, persistent AF can progress into permanent AF.

Permanent AF, also known as Accepted AF, refers to episodes that cannot be successfully terminated, have relapsed after termination, or where cardioversion is not pursued. This subtype signifies a more chronic and ongoing form of AF.

By understanding and utilizing these terms, healthcare professionals can effectively communicate and manage the different subtypes of AF.

One of the signs of digoxin toxicity is yellow-green vision. Other clinical features include feeling generally unwell, lethargy, nausea and vomiting, loss of appetite, confusion, and the development of arrhythmias such as AV block and bradycardia.

Further Reading:

Digoxin is a medication used for rate control in atrial fibrillation and for improving symptoms in heart failure. It works by decreasing conduction through the atrioventricular node and increasing the force of cardiac muscle contraction. However, digoxin toxicity can occur, and plasma concentration alone does not determine if a patient has developed toxicity. Symptoms of digoxin toxicity include feeling generally unwell, lethargy, nausea and vomiting, anorexia, confusion, yellow-green vision, arrhythmias, and gynaecomastia.

ECG changes seen in digoxin toxicity include downsloping ST depression with a characteristic Salvador Dali sagging appearance, flattened, inverted, or biphasic T waves, shortened QT interval, mild PR interval prolongation, and prominent U waves. There are several precipitating factors for digoxin toxicity, including hypokalaemia, increasing age, renal failure, myocardial ischaemia, electrolyte imbalances, hypoalbuminaemia, hypothermia, hypothyroidism, and certain medications such as amiodarone, quinidine, verapamil, and diltiazem.

Management of digoxin toxicity involves the use of digoxin specific antibody fragments, also known as Digibind or digifab. Arrhythmias should be treated, and electrolyte disturbances should be corrected with close monitoring of potassium levels. It is important to note that digoxin toxicity can be precipitated by hypokalaemia, and toxicity can then lead to hyperkalaemia.

This patient is likely experiencing an acute coronary syndrome, possibly a non-ST-elevation myocardial infarction (NSTEMI) or unstable angina. The troponin test will help confirm the diagnosis. The patient’s ECG showed ST depression in the inferior leads, but this normalized after treatment with GTN and morphine, ruling out a ST-elevation myocardial infarction (STEMI).

Immediate pain relief should be provided. GTN (sublingual or buccal) can be used, but intravenous opioids like morphine should be considered, especially if a heart attack is suspected.

Aspirin should be given to all patients with unstable angina or NSTEMI as soon as possible and continued indefinitely, unless there are contraindications like bleeding risk or aspirin hypersensitivity. A loading dose of 300 mg should be administered right after presentation.

Fondaparinux should be given to patients without a high bleeding risk, unless coronary angiography is planned within 24 hours of admission. Unfractionated heparin can be an alternative to fondaparinux for patients who will undergo coronary angiography within 24 hours. For patients with significant renal impairment, unfractionated heparin can also be considered, with dose adjustment based on clotting function monitoring.

Routine administration of oxygen is no longer recommended, but oxygen saturation should be monitored using pulse oximetry as soon as possible, preferably before hospital admission. Supplemental oxygen should only be offered to individuals with oxygen saturation (SpO2) below 94% who are not at risk of hypercapnic respiratory failure, aiming for a SpO2 of 94-98%. For individuals with chronic obstructive pulmonary disease at risk of hypercapnic respiratory failure, a target SpO2 of 88-92% should be achieved until blood gas analysis is available.

Bivalirudin, a specific and reversible direct thrombin inhibitor (DTI), is recommended by NICE as a possible treatment for adults with STEMI undergoing percutaneous coronary intervention.

For more information, refer to the NICE guidelines on the assessment and diagnosis of chest pain of recent onset.

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

The ECG shows the following findings:
– There is ST depression in leads V1-V4 and aVR.
– There is ST elevation in leads V5-V6, II, III, and aVF.
– There is a positive R wave in leads V1 and V2, which indicates a reverse Q wave.
These ECG changes indicate that there is an acute inferoposterior myocardial infarction.

According to NICE guidelines, the usual threshold score for initiating anticoagulation in this case is 2.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting around 5% of patients over the age of 70-75 years and 10% of patients aged 80-85 years. While AF can cause palpitations and inefficient cardiac function, the most important aspect of managing patients with AF is reducing the increased risk of stroke.

AF can be classified as first detected episode, paroxysmal, persistent, or permanent. First detected episode refers to the initial occurrence of AF, regardless of symptoms or duration. Paroxysmal AF occurs when a patient has 2 or more self-terminating episodes lasting less than 7 days. Persistent AF refers to episodes lasting more than 7 days that do not self-terminate. Permanent AF is continuous atrial fibrillation that cannot be cardioverted or if attempts to do so are deemed inappropriate. The treatment goals for permanent AF are rate control and anticoagulation if appropriate.

Symptoms of AF include palpitations, dyspnea, and chest pain. The most common sign is an irregularly irregular pulse. An electrocardiogram (ECG) is essential for diagnosing AF, as other conditions can also cause an irregular pulse.

Managing patients with AF involves two key parts: rate/rhythm control and reducing stroke risk. Rate control involves slowing down the irregular pulse to avoid negative effects on cardiac function. This is typically achieved using beta-blockers or rate-limiting calcium channel blockers. If one drug is not effective, combination therapy may be used. Rhythm control aims to restore and maintain normal sinus rhythm through pharmacological or electrical cardioversion. However, the majority of patients are managed with a rate control strategy.

Reducing stroke risk in patients with AF is crucial. Risk stratifying tools, such as the CHA2DS2-VASc score, are used to determine the most appropriate anticoagulation strategy. Anticoagulation is recommended for patients with a score of 2 or more. Clinicians can choose between warfarin and novel oral anticoagulants (NOACs) for anticoagulation.

Before starting anticoagulation, the patient’s bleeding risk should be assessed using tools like the HAS-BLED score or the ORBIT tool. These tools evaluate factors such as hypertension, abnormal renal or liver function, history of bleeding, age, and use of drugs that predispose to bleeding.

The ratio of chest compressions to ventilations is 15:2. This ratio has not been proven through experiments, but it has been validated through mathematical studies. When performing chest compressions on a child, it is recommended to make them at least 1/3 of the depth of the child’s chest. Additionally, the optimal compression rate is between 100 and 120 compressions per minute.
To protect the airway of an unconscious child, the oropharyngeal (Guedel) airway is the best option. However, it should not be used on awake patients as there is a risk of vomiting and aspiration.
In children, asystole is the most common arrest rhythm. This occurs when the young heart responds to prolonged hypoxia and acidosis by progressively slowing down, eventually resulting in asystole.

This particular patient has a high risk of experiencing an acute coronary syndrome. Therefore, it is recommended to administer aspirin at a dosage of 300 mg and clopidogrel at a dosage ranging from 300-600 mg.

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.

Hypothermia can cause various changes in an electrocardiogram (ECG). These changes include a slower heart rate (bradycardia), the presence of Osborn Waves (also known as J waves), a prolonged PR interval, a widened QRS complex, and a prolonged QT interval. Additionally, the ECG may show artifacts caused by shivering, as well as the presence of ventricular ectopics. In severe cases, hypothermia can lead to cardiac arrest, which may manifest as ventricular tachycardia (VT), ventricular fibrillation (VF), or asystole.

Further Reading:

Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, the basal metabolic rate decreases and cell signaling between neurons decreases, leading to reduced tissue perfusion. This can result in decreased myocardial contractility, vasoconstriction, ventilation-perfusion mismatch, and increased blood viscosity. Symptoms of hypothermia progress as the core temperature drops, starting with compensatory increases in heart rate and shivering, and eventually leading to bradyarrhythmias, prolonged PR, QRS, and QT intervals, and cardiac arrest.

In the management of hypothermic cardiac arrest, ALS should be initiated with some modifications. The pulse check during CPR should be prolonged to 1 minute due to difficulty in obtaining a pulse. Rewarming the patient is important, and mechanical ventilation may be necessary due to stiffness of the chest wall. Drug metabolism is slowed in hypothermic patients, so dosing of drugs should be adjusted or withheld. Electrolyte disturbances are common in hypothermic patients and should be corrected.

Frostbite refers to a freezing injury to human tissue and occurs when tissue temperature drops below 0ºC. It can be classified as superficial or deep, with superficial frostbite affecting the skin and subcutaneous tissues, and deep frostbite affecting bones, joints, and tendons. Frostbite can be classified from 1st to 4th degree based on the severity of the injury. Risk factors for frostbite include environmental factors such as cold weather exposure and medical factors such as peripheral vascular disease and diabetes.

Signs and symptoms of frostbite include skin changes, cold sensation or firmness to the affected area, stinging, burning, or numbness, clumsiness of the affected extremity, and excessive sweating, hyperemia, and tissue gangrene. Frostbite is diagnosed clinically and imaging may be used in some cases to assess perfusion or visualize occluded vessels. Management involves moving the patient to a warm environment, removing wet clothing, and rapidly rewarming the affected tissue. Analgesia should be given as reperfusion is painful, and blisters should be de-roofed and aloe vera applied. Compartment syndrome is a risk and should be monitored for. Severe cases may require surgical debridement of amputation.

Adenosine is a type of purine nucleoside that is primarily utilized in the diagnosis and treatment of paroxysmal supraventricular tachycardia. Its main mechanism of action involves stimulating A1-adenosine receptors and opening acetylcholine-sensitive potassium channels. This leads to hyperpolarization of the cell membrane in the atrioventricular (AV) node and slows down conduction in the AV node by inhibiting calcium channels.

When administering adenosine, it is given rapidly through an intravenous bolus, followed by a saline flush. The initial dose for adults is 6 mg, and if necessary, additional doses of 12 mg or 18 mg can be given at 1-2 minute intervals until the desired effect is observed. It is important to note that the latest ALS guidelines recommend 18 mg for the third dose, while the BNF/NICE guidelines suggest 12 mg.

One of the advantages of adenosine is its very short half-life, which is less than 10 seconds. This means that its effects are rapid, typically occurring within 10 seconds. However, the duration of action is also short, lasting only 10-20 seconds. Due to its short half-life, any side effects experienced are usually brief. These side effects may include a sense of impending doom, facial flushing, dyspnea, chest discomfort, and a metallic taste.

There are certain contraindications to the use of adenosine. These include 2nd or 3rd degree AV block, sick sinus syndrome, long QT syndrome, severe hypotension, decompensated heart failure, chronic obstructive lung disease, and asthma. It is important to exercise caution when administering adenosine to patients with a heart transplant, as they are particularly sensitive to its effects. In these cases, a reduced initial dose of 3 mg is recommended, followed by 6 mg and then 12 mg.

It is worth noting that the effects of adenosine can be potentiated by dipyridamole, a medication commonly used in combination with adenosine. Therefore, the dose of adenosine should be adjusted and reduced in patients who are also taking dipyridamole.

Severe aortic stenosis is characterized by several distinct features. These include a narrow pulse pressure, which refers to the difference between the systolic and diastolic blood pressure readings. Additionally, individuals with severe aortic stenosis may exhibit a slow rising pulse, meaning that the pulse wave takes longer to reach its peak. Another common feature is a delayed ejection systolic murmur, which is a heart sound that occurs during the ejection phase of the cardiac cycle. The second heart sound (S2) may also be soft or absent in individuals with severe aortic stenosis. Another potential finding is the presence of an S4 heart sound, which occurs during the filling phase of the cardiac cycle. A thrill, which is a palpable vibration, may also be felt in severe cases. The duration of the murmur, as well as the presence of left ventricular hypertrophy or failure, are additional features that may be observed in individuals with severe aortic stenosis.

Further Reading:

Valvular heart disease refers to conditions that affect the valves of the heart. In the case of aortic valve disease, there are two main conditions: aortic regurgitation and aortic stenosis.

Aortic regurgitation is characterized by an early diastolic murmur, a collapsing pulse (also known as a water hammer pulse), and a wide pulse pressure. In severe cases, there may be a mid-diastolic Austin-Flint murmur due to partial closure of the anterior mitral valve cusps caused by the regurgitation streams. The first and second heart sounds (S1 and S2) may be soft, and S2 may even be absent. Additionally, there may be a hyperdynamic apical pulse. Causes of aortic regurgitation include rheumatic fever, infective endocarditis, connective tissue diseases like rheumatoid arthritis and systemic lupus erythematosus, and a bicuspid aortic valve. Aortic root diseases such as aortic dissection, spondyloarthropathies like ankylosing spondylitis, hypertension, syphilis, and genetic conditions like Marfan’s syndrome and Ehler-Danlos syndrome can also lead to aortic regurgitation.

Aortic stenosis, on the other hand, is characterized by a narrow pulse pressure, a slow rising pulse, and a delayed ESM (ejection systolic murmur). The second heart sound (S2) may be soft or absent, and there may be an S4 (atrial gallop) that occurs just before S1. A thrill may also be felt. The duration of the murmur is an important factor in determining the severity of aortic stenosis. Causes of aortic stenosis include degenerative calcification (most common in older patients), a bicuspid aortic valve (most common in younger patients), William’s syndrome (supravalvular aortic stenosis), post-rheumatic disease, and subvalvular conditions like hypertrophic obstructive cardiomyopathy (HOCM).

Management of aortic valve disease depends on the severity of symptoms. Asymptomatic patients are generally observed, while symptomatic patients may require valve replacement. Surgery may also be considered for asymptomatic patients with a valvular gradient greater than 40 mmHg and features such as left ventricular systolic dysfunction. Balloon valvuloplasty is limited to patients with critical aortic stenosis who are not fit for valve replacement.

Unstable angina is characterized by the presence of one or more of the following symptoms: angina of effort occurring over a few days with increasing frequency, episodes of angina occurring recurrently and predictably without specific provocation, or an unprovoked and prolonged episode of cardiac chest pain. The electrocardiogram (ECG) may appear normal or show T-wave/ST-segment changes, and cardiac enzymes are typically within normal range.

On the other hand, stable angina is defined by central chest pain that is triggered by activities such as exercise and emotional stress. This pain may radiate to the jaw or left arm and is relieved by resting for a few minutes. It is usually brought on by a predictable amount of exertion.

Prinzmetal angina, although rare, is a variant of angina that primarily occurs at rest between midnight and early morning. The attacks can be severe and tend to happen in clusters. This type of angina is caused by coronary artery spasm, and patients may have normal coronary arteries.

Decubitus angina, on the other hand, is angina that occurs when lying down. It often develops as a result of cardiac failure due to an increased volume of blood within the blood vessels, which places additional strain on the heart.

Lastly, Ludwig’s angina is an extremely serious and potentially life-threatening cellulitis that affects the submandibular area. It most commonly arises from an infection in the floor of the mouth, which then spreads to the submandibular space.

A summary of the vessels involved in different types of myocardial infarction, along with the corresponding ECG leads and the location of the infarction.

For instance, an anteroseptal infarction involving the left anterior descending artery is indicated by ECG leads V1-V3. Similarly, an anterior infarction involving the left anterior descending artery is indicated by leads V3-V4.

In cases of anterolateral infarctions, both the left anterior descending artery and the left circumflex artery are involved, and this is reflected in ECG leads V5-V6. An extensive anterior infarction involving the left anterior descending artery is indicated by leads V1-V6.

Lateral infarcts involving the left circumflex artery are indicated by leads I, II, aVL, and V6. Inferior infarctions, on the other hand, involve either the right coronary artery (in 80% of cases) or the left circumflex artery (in 20% of cases), and this is shown by leads II, III, and aVF.

In the case of a right ventricular infarction, the right coronary artery is involved, and this is indicated by leads V1 and V4R. Lastly, a posterior infarction involving the right coronary artery is shown by leads V7-V9.