Electrocardiography (ECG) is an essential tool in clinical practice, used for diagnosing arrhythmias, myocardial infarctions, electrolyte imbalances, and various cardiac conditions. Despite its ubiquity, ECG interpretation requires a structured approach to ensure accurate diagnosis and appropriate clinical management. This article provides a detailed yet practical guide for medical professionals, breaking down ECG interpretation into a stepwise approach. It includes key considerations for rhythm analysis, conduction abnormalities, ischemic changes, and electrolyte disturbances, with reference to relevant guidelines. Further Reading: NICE Guidelines on ECG Interpretation 2. Basic Principles of ECG An ECG records the electrical activity of the heart as it propagates…
Author: Dr Ben
Arrhythmias are disturbances in cardiac rhythm that can range from benign to life-threatening. This article provides a comprehensive comparison of Atrial Fibrillation (AF), Atrial Flutter, Supraventricular Tachycardia (SVT), Ventricular Tachycardia (VT), Ventricular Fibrillation (VF), and Torsades de Pointes (TdP), including their ECG findings, causes, symptoms, and management. 2. Overview of Arrhythmias Arrhythmia ECG Characteristics Origin Heart Rate Clinical Features Atrial Fibrillation (AF) Irregularly irregular rhythm, no P waves, fibrillatory waves Atria 100-175 bpm Palpitations, stroke risk, dyspnea, fatigue Atrial Flutter Sawtooth flutter waves, regular rhythm Atria ~150 bpm Palpitations, dizziness, heart failure symptoms Supraventricular Tachycardia (SVT) Narrow QRS, P waves…
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, characterized by irregular, rapid atrial electrical activity leading to ineffective atrial contraction. It significantly increases the risk of stroke, heart failure, and mortality. 2. Classification of Atrial Fibrillation Type Duration Characteristics Paroxysmal AF <7 days (self-terminating) Spontaneously resolves within 48 hours – 7 days Persistent AF >7 days Requires cardioversion for termination Long-standing Persistent AF >12 months May not respond to rhythm control Permanent AF Persistent despite attempts at cardioversion Rate control is the primary strategy 3. Causes and Risk Factors Category Common Causes Cardiac Causes Hypertension, ischemic heart disease,…
Infective Endocarditis (IE) is a life-threatening infection of the heart’s endocardium, most commonly affecting heart valves. It can lead to valvular destruction, heart failure, embolic events, and multi-organ complications. Early recognition and treatment are crucial to reduce morbidity and mortality. 2. Classification of Infective Endocarditis Type Description Acute IE Rapid onset, highly virulent organisms (e.g., Staphylococcus aureus), aggressive progression Subacute IE Indolent course, less virulent organisms (e.g., Streptococcus viridans), occurs on pre-existing valve disease Native Valve Endocarditis (NVE) Infection on natural heart valves Prosthetic Valve Endocarditis (PVE) Infection on prosthetic heart valves (early: <1 year post-surgery, late: >1 year post-surgery)…
Hypertension, commonly known as high blood pressure, is a chronic medical condition characterized by elevated blood pressure levels. It significantly increases the risk of cardiovascular diseases, including stroke, myocardial infarction, heart failure, and kidney disease. Effective management of hypertension involves accurate diagnosis, lifestyle modifications, pharmacological interventions, and regular monitoring to prevent complications. 2. Diagnosis and Classification of Hypertension (A) Blood Pressure Measurement Accurate measurement of blood pressure (BP) is crucial for diagnosis. The American Heart Association emphasizes proper techniques to ensure reliable readings, such as correct arm positioning and using appropriately sized cuffs. citeturn0search7 (B) Classification by Guidelines NICE Guidelines…
Congenital heart diseases (CHDs) are structural abnormalities of the heart present at birth. They range from simple, asymptomatic defects to severe, life-threatening conditions requiring urgent intervention. Advances in fetal screening, surgical correction, and catheter-based interventions have improved survival rates, allowing many CHD patients to reach adulthood. 2. Classification of Congenital Heart Diseases CHDs are classified based on cyanosis, shunting patterns, and structural defects. (A) Classification by Cyanosis Category Description Examples Acyanotic CHDs (Left-to-Right Shunts) Increased pulmonary blood flow ASD, VSD, PDA, AVSD Cyanotic CHDs (Right-to-Left Shunts) Deoxygenated blood enters systemic circulation Tetralogy of Fallot, Transposition of Great Arteries (B) Classification…
Arrhythmias are abnormal heart rhythms caused by disturbances in impulse formation or conduction. Management includes antiarrhythmic drugs (AADs), electrical interventions (cardioversion, pacemakers), and catheter ablation. Proper selection of antiarrhythmic therapy depends on the type of arrhythmia, hemodynamic stability, and underlying heart disease. 2. Classification of Antiarrhythmic Drugs (Vaughan-Williams Classification) Class Mechanism of Action Examples Indications Class I (Sodium Channel Blockers) Slows depolarization (Phase 0) Quinidine, Procainamide, Lidocaine, Flecainide SVT, VT, AF (not first-line) Class II (Beta-Blockers) Decreases SA & AV node activity Metoprolol, Esmolol, Propranolol AF, SVT, rate control Class III (Potassium Channel Blockers) Prolongs repolarization (Phase 3) Amiodarone, Sotalol,…
Atrioventricular (AV) block is an abnormal delay or interruption in the conduction of electrical impulses from the atria to the ventricles. It can range from mild (first-degree block) to severe (third-degree block, complete heart block). Recognizing AV block on an ECG is critical, as higher-degree blocks may require pacemaker implantation. 2. Classification of AV Blocks Type ECG Findings Clinical Features First-Degree AV Block PR interval >200ms (prolonged but constant) Usually asymptomatic Second-Degree AV Block – Mobitz Type I (Wenckebach) Progressive PR prolongation → Dropped QRS May cause dizziness, rarely progresses Second-Degree AV Block – Mobitz Type II Sudden dropped QRS…
Hypertrophic Obstructive Cardiomyopathy (HOCM) is a genetic disorder characterized by left ventricular hypertrophy (LVH) and dynamic outflow tract obstruction. It is a leading cause of sudden cardiac death (SCD) in young athletes due to arrhythmias and left ventricular outflow tract (LVOT) obstruction. 2. Causes and Pathophysiology (A) Causes Genetic mutation (autosomal dominant) in sarcomere proteins: Beta-myosin heavy chain (MYH7) Myosin-binding protein C (MYBPC3) Family history of sudden cardiac death is a key risk factor. (B) Pathophysiology Asymmetric septal hypertrophy → Left Ventricular Outflow Tract (LVOT) obstruction Diastolic dysfunction → Impaired ventricular filling → Increased left atrial pressure Mitral valve involvement…
Acute pericarditis is the inflammation of the pericardium, the fibrous sac surrounding the heart. It presents with chest pain, pericardial friction rub, and characteristic ECG changes. Early recognition is crucial to prevent complications such as cardiac tamponade and constrictive pericarditis. 2. Causes of Acute Pericarditis Acute pericarditis can be idiopathic or caused by infections, autoimmune diseases, malignancies, or metabolic disorders. (A) Infectious Causes Viral (most common): Coxsackievirus, influenza, echovirus, HIV Bacterial: Tuberculosis, Staphylococcus, Streptococcus pneumoniae Fungal: Histoplasmosis, Aspergillus (rare) (B) Non-Infectious Causes Post-myocardial infarction: Early pericarditis (1-3 days post-MI) Dressler’s syndrome (autoimmune, weeks post-MI) Autoimmune Diseases: SLE, rheumatoid arthritis, scleroderma…
A heart murmur is an abnormal sound heard during the cardiac cycle due to turbulent blood flow. It may be innocent (physiological) or indicate underlying valvular or structural heart disease. Proper assessment of murmurs requires understanding timing, location, radiation, pitch, and maneuvers. 2. Classification of Heart Murmurs Heart murmurs are classified based on timing in the cardiac cycle and clinical characteristics. (A) Based on Timing Type Occurs During Common Causes Systolic Murmurs Between S1 and S2 Aortic stenosis, mitral regurgitation, VSD Diastolic Murmurs Between S2 and S1 Aortic regurgitation, mitral stenosis Continuous Murmurs Throughout systole & diastole Patent ductus arteriosus…
1. Introduction Hypertension (HTN) is a chronic elevation of blood pressure (BP) and a leading risk factor for cardiovascular disease (CVD), stroke, renal failure, and heart failure. It is often asymptomatic, earning it the name “silent killer.” Early detection and effective management significantly reduce morbidity and mortality. 2. Definition and Classification of Hypertension Blood pressure is measured in millimeters of mercury (mmHg) and classified according to NICE and European Society of Cardiology (ESC) guidelines. (A) Blood Pressure Categories Category Systolic BP (mmHg) Diastolic BP (mmHg) Normal BP <120 <80 Elevated BP (Prehypertension) 120-129 <80 Hypertension Stage 1 130-139 80-89 Hypertension…