title: Correlation of pathologic Q waves on the standard electrocardiogram and the epicardial electrogram of the human heart.
abstract: To evaluate the relationship between abnormal Q waves on the standard ECG and localized ventricular excitation, unipolar epicardial electrograms were recorded over the left ventricle during aortocoronary bypass surgery in 36 patients. Of 20 without standard ECG Q waves, six had abnormal epicardial Q waves, three anterioly and three inferiorly. Of 16 patients with standard ECG Q waves, four had both precordial and anterior epicardial Q waves while seven had Q waves in leads III and aVF and inferior epicardial Q waves. Three of the 14 had Q waves in both precordial and inferior leads of the ECG but epicardial Q waves only from the antero-apical region in two and only from the inferior wall in one. Two patients with Q waves in both III and aVF had no epicardial Q waves. Thus, the standard electocardiogram underestimates epicardial Q waves. If Q waves are present in the standard ECG, they correlate with the presence, although not invariably the location of Q waves on the epicardial electrogram.
mesh_terms: D006328:Cardiac Catheterization; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000503:physiopathology* / Q000601:surgery; D004562:Electrocardiography / Q000379:methods*; D006322:Heart Aneurysm / Q000601:surgery; D006329:Heart Conduction System / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D009200:Myocardial Contraction; D009435:Synaptic Transmission