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,…
Author: Dr Ben
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…
1. Introduction to Stroke A stroke is an acute neurological deficit caused by disruption of blood flow to the brain, leading to infarction (ischemic stroke) or hemorrhage (hemorrhagic stroke). Ischemic strokes account for about 80% of all strokes, while hemorrhagic strokes account for 20%. Understanding the vascular territories of the brain is essential for localizing strokes and predicting their clinical manifestations. 2. Classification of Stroke (A) Ischemic Stroke (80%) Caused by thrombosis, embolism, or systemic hypoperfusion, leading to brain infarction. Cause Examples Thrombotic Atherosclerosis (large vessel disease), lacunar infarcts (small vessel disease) Embolic Cardioembolism (AF, endocarditis), carotid stenosis Watershed (Hypoperfusion)…
The cranial nerves (CN) are 12 pairs of nerves emerging from the brainstem, responsible for sensory, motor, and autonomic functions. Their lesions present with distinct clinical signs, making them a crucial topic in neurology and clinical practice. 1. Overview of Cranial Nerves Cranial Nerve Function Clinical Sign of Lesion I. Olfactory (Sensory) Smell Anosmia (loss of smell) II. Optic (Sensory) Vision, pupillary reflex Visual field loss, afferent pupillary defect III. Oculomotor (Motor, Parasymp.) Eye movement (except LR6, SO4), pupillary constriction Ptosis, down & out eye, pupil dilation IV. Trochlear (Motor) Superior oblique (SO4) Vertical diplopia, worsens on downward gaze V.…
A hernia is the abnormal protrusion of an organ or tissue through a defect in the surrounding structures that usually contain it. This commonly occurs in the abdominal wall, involving the intestines or other intra-abdominal contents. Understanding hernia anatomy, classification, and clinical implications is essential for accurate diagnosis and management. 1. Basic Anatomy of a Hernia A hernia consists of three main components: Component Description Hernial Sac The peritoneal outpouching containing the herniated contents. Hernial Ring The defect in the fascia or muscle through which the contents protrude. Hernial Contents May include bowel, omentum, or other intra-abdominal structures. 2. Classification…
The hepatobiliary system plays a critical role in metabolism, detoxification, digestion, and waste elimination. It includes the liver, gallbladder, and bile ducts, forming a complex network essential for maintaining homeostasis. This article covers its anatomy, function, clinical significance, and diagnostic approach. 1. Anatomy of the Hepatobiliary System The hepatobiliary system consists of: Liver – Largest gland, responsible for metabolism and detoxification. Gallbladder – Stores and concentrates bile. Biliary tree – Transports bile from the liver to the duodenum. Liver Anatomy Lobes: Right and left lobes (divided by the falciform ligament). Microscopic structure: Contains hepatocytes organized into lobules with a central…
The brachial plexus is a vital nerve network supplying the upper limb, frequently encountered in clinical practice due to its involvement in trauma, nerve compression syndromes, and surgical procedures. A thorough understanding of its anatomy, function, and injury patterns is crucial for accurate diagnosis and management. 1. Anatomy of the Brachial Plexus The brachial plexus originates from the ventral rami of C5-T1 and extends from the neck into the axilla, providing motor and sensory innervation to the upper limb. Structural Organization (Mnemonic: Remember To Drink Cold Beer) The plexus is systematically divided into five regions: Part Mnemonic Details Roots Remember…
Pulmonary embolism (PE), venous thromboembolism (VTE), and fat embolism (FE) are all types of embolic disorders that involve obstruction of blood vessels, leading to significant morbidity and mortality. Understanding their differences, diagnostic approaches, and clinical features is crucial for effective management. 1. Overview and Differences Feature Pulmonary Embolism (PE) Venous Thromboembolism (VTE) Fat Embolism (FE) Definition A blockage of pulmonary arteries due to a thrombus (commonly from deep veins). A collective term for deep vein thrombosis (DVT) and pulmonary embolism (PE). Embolization of fat droplets, often following trauma or orthopedic surgery. Etiology Most commonly from deep vein thrombosis (DVT) in…