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Changes in ECG
Pathological Changes in ECG
Question | Answer |
---|---|
Depressed QRS | Heart failure, ischemia, pericardial effusion, obesity, COPD |
Elevated QRS | Hypertrophy of myocardium |
Q wave | Previous MI |
ST segment elevation | Acute MI |
Atrial Fibrillation (A. Fib) | Irregular atrial rhythm, no rate, P waves are abnormal or not identifiable "F" waves absent, quivers noted, ventricular rhythm varies CO is usually maintained Common causes: HTN, CHF, CAD, rheumatic heart disease, cor pulmonale, pericarditis |
Supraventricular Tachycardia | Rate varies 160-250 bpm, regular rhythm Common causes: mitral valve prolapse, cor pulmonale, digitalis toxicity, rheumatic heart disease |
Ventricular Fibrillation (V.fib) | No regular rate or rhythm, emergency, require immediate medical attention Erratic activity without QRS wave No effective CO; clinical death in 4-6 minutes Common causes: post MI, long term or severe heart disease, hypercalcemia, hypo and hyper kalemia |
Premature Atrial Contractions (PAC) | P wave is premature with abnormal configuration Rate is normal Indicative of ischemia or valve pathology Common causes: caffeine intake, emotional stress, smoking, CAD, CHF, infection, electrolyte imbalance. |
Ventricular Tachycardia (VT) | Rate > 100 bpm, rhythm usually regular No P wave or it appears after QRS complex with retrograde conduction; Wide bizarre QRS waves Requires immediate medical attention Common causes: post MI, rheumatic heart disease, CAD, cardiomyopathy Compromised |
Premature Ventricular Contractions (PVC) | Rate is normal (60-100 bpm) P wave absent, ST segment distorted, QRS complex occurs early Common causes: caffeine intake, emotional stress, smoking, CAD, MI, cardiomyopathy, digitalis toxicity. |
Complex heart block (3rd degree AV block) | Regular rhythm Requires immediate medical intervention (pacemaker) Common causes: CAD, infection, electrolyte imbalance, anteroseptal MI, impairment with AV conduction system. |
Multifocal Ventricular Tachycardia | Rate > 150 bpm, irregular rhythm No P waves, QRS complex is wide, require immediate medical attention Common causes: hypokalemia, hypomagnesemia, hypothermia, drug-induced through antiarrhythmic medications. |
Asystole | No rhythm Absence of P waves, QRS, and T wave Can have abrupt onset and requires immediate medical attention Common causes: failure of all pacemakers to initiate, conduction system failure, acute MI, ventricular rupture. |
Ischemia | Inverted T wave |
ST depression | May indicate ischemia if downsloping 2-3 mm |
ST elevation | Shows new infarct, injury, or pericarditis |