Noninfarction Q Waves on ECG: Differential Diagnosis and Clinical Approach Q waves on an electrocardiogram (ECG) are often associated with previous myocardial infarction (MI). However, an important clinical principle is: Not every Q wave represents myocardial infarction. Q waves can occur as normal variants or as a result of changes in cardiac position, ventricular hypertrophy, cardiomyopathy, myocardial infiltration, and conduction abnormalities. Recognizing these noninfarction Q waves is important because an incorrect diagnosis of previous MI may lead to unnecessary investigations, anxiety, and inappropriate treatment. This article provides a practical differential diagnosis of Q waves that may occur without myocardial infarction. --- What Is a Q Wave? A Q wave is the first negative deflection of the QRS complex occurring before the first positive deflection (R wave). Small Q waves can be entirely physiological because normal ventricular depolarization begins in the interventricular ...
Dr. Usman's Cardiology Notes
Cardiology Notes: Clinical Cases including ECG, Echocardiography, Cath, and MOCK Exams to sharpen your cardiology data interpretation skills. Healthcare is stressful!!! Learning cardiology shouldn't be !!!