Dr. Usman's Cardiology Notes

STEPWISE ALGORITHM: ACID–BASE DISORDER INTERPRETATION START → CHECK pH ↓ pH < 7.35 → ACIDEMIA pH > 7.45 → ALKALEMIA ↓ CHECK PRIMARY CHANGE • PaCO₂ abnormal → RESPIRATORY • HCO₃⁻ abnormal → METABOLIC ↓ ASSESS COMPENSATION • Metabolic acidosis → Winter’s formula • Metabolic alkalosis → Expected PaCO₂ rise • Respiratory disorders → Acute vs chronic pattern ↓ IF METABOLIC ACIDOSIS → CALCULATE ANION GAP AG = Na⁺ − (Cl⁻ + HCO₃⁻) • AG 8–12 → Normal AG acidosis • AG >12 → High AG acidosis ↓ CHECK FOR MIXED DISORDERS • Normal pH with abnormal PaCO₂ & HCO₃⁻ • Compensation inappropriate • Use delta gap if needed END → CORRELATE WITH CLINICAL CONTEXT For more infographics visit: drmusmanjaved.com  

   Acid–base disorders are common clinical problems resulting from disturbances in hydrogen ion (H⁺) balance. Understanding them is essential for interpreting arterial blood gases (ABGs), managing critically ill patients, and identifying underlying systemic diseases. --- Acid–Base Physiology (Quick Review) Normal arterial values pH: 7.35–7.45 PaCO₂: 35–45 mmHg (respiratory component) HCO₃⁻: 22–26 mEq/L (metabolic component) Key relationship (Henderson–Hasselbalch concept): pH depends on the ratio of HCO₃⁻ (kidney) to PaCO₂ (lungs) --- Classification of Acid–Base Disorders There are four primary acid–base disorders: 1. Metabolic Acidosis 2. Metabolic Alkalosis 3. Respiratory Acidosis 4. Respiratory Alkalosis Each primary disorder triggers a predictable compensatory response. --- 1. Metabolic Acidosis Definition ↓ pH, ↓ HCO₃⁻ Mechanisms • Increased acid production • Loss of bicarbonate • Reduced acid excretion Anion Gap (AG) AG = Na⁺ − (Cl⁻ + HCO₃⁻) Normal: 8–12 mEq/L High Anion...

Romano-Ward syndrome vs Jervell–Lange-Nielsen syndrome A Detailed Clinical Review of Congenital Long QT Syndromes Congenital Long QT Syndromes (LQTS) are inherited cardiac channelopathies characterized by delayed ventricular repolarization, leading to QT interval prolongation on ECG and a high risk of malignant ventricular arrhythmias. Among these, Romano–Ward syndrome and Jervell–Lange-Nielsen (JLN) syndrome represent two classic but clinically distinct entities. --- Overview of Congenital Long QT Syndrome LQTS results from mutations in genes encoding cardiac ion channels, primarily potassium and sodium channels. The hallmark is QT prolongation, predisposing patients to polymorphic ventricular tachycardia, especially Torsades de Pointes, which may degenerate into ventricular fibrillation and cause sudden cardiac death. Common clinical manifestations include: Syncope (often exercise- or stress-related) Seizure-like episodes Sudden cardiac arrest, particularly in young individuals --- R...

  Vernakalant: Mechanism of Action Explained (Atrial-Selective Antiarrhythmic) Vernakalant is an intravenous antiarrhythmic drug specifically developed for rapid pharmacological cardioversion of recent-onset atrial fibrillation (AF). Its unique value lies in atrial selectivity, providing effective AF termination with minimal ventricular proarrhythmic risk. --- What Makes Vernakalant Different? Unlike traditional Class I or Class III antiarrhythmic drugs that affect both atria and ventricles, vernakalant primarily targets ion channels predominantly expressed in atrial myocardium. This atrial selectivity is the cornerstone of its safety and efficacy. --- Core Mechanism of Action 1. Blockade of Atrial Potassium Currents Vernakalant blocks potassium currents that are mainly present in atrial cells: IKur (Ultra-rapid delayed rectifier K⁺ current) Found almost exclusively in atria Responsible for atrial repolarization Blockade leads to prolongation of atrial action potential duration IKA...

Measurement of Fractional Area Change (FAC) of the Right Ventricle Introduction Assessment of right ventricular (RV) systolic function is an essential component of echocardiography, as RV dysfunction carries important diagnostic and prognostic implications in many cardiovascular diseases. Fractional Area Change (FAC) is a simple, reproducible, and guideline-recommended echocardiographic parameter used to quantify global RV systolic function. What is Right Ventricular Fractional Area Change (RV FAC)? RV FAC is a two-dimensional echocardiographic measurement that represents the percentage change in RV cavity area between end-diastole and end-systole. It reflects longitudinal and radial contraction of the RV and correlates reasonably well with RV ejection fraction measured by cardiac MRI. Formula for RV FAC RV FAC (%) = [(RV End-Diastolic Area − RV End-Systolic Area) ÷ RV End-Diastolic Area] × 100 Echocardiographic View Required • RV-focused apical four-chamber view • The RV should be cen...

📍 Medical Triads Medical triads are sets of three important clinical features (symptoms, signs, or findings) that tend to appear together and help clinicians quickly identify and diagnose specific conditions. 🚨 Why medical triads matter 🎓 Simple to memorize for exams ⚡ Aid in fast bedside diagnosis 📚 Frequently tested in medicine, nursing, and allied health sciences

Top 10 Cardiology Mnemonics 1. Causes of Chest Pain – RAT PLACES R – Reflux A – Aortic dissection T – Trauma P – Pneumonia / Pneumothorax L – Lung (PE) A – Angina / MI C – Costochondritis E – Esophageal spasm S – Shingles 2. Causes of Reversible Secondary Hypertension – CHAPS C – Coarctation of aorta H – Hyperaldosteronism A – Apnea (OSA) P – Pheochromocytoma S – Stenosis (renal artery) 3. Diastolic Murmurs – PR ARD P – Pulmonary regurgitation R – Rheumatic (mitral stenosis) A – Austin Flint murmur R – Ruptured papillary muscle (functional MS) D – Aortic regurgitation 4. Causes of Dilated Cardiomyopathy – ABCD FRESH A – Alcohol B – Beriberi C – Coxsackie / Cocaine D – Doxorubicin F – Familial R – Rheumatic E – Endocrine S – Sepsis H – Hemochromatosis 5. ECG Causes of Tall T Waves – MI HAT M – Myocardial infarction (hyperacute) I – Ischemia H – Hyperkalemia A – Acute pericarditis T – Tall normal variant 6. Causes of Left Ventricular Hypertrophy – HARD H – Hypertension A – Aortic stenosi...