title: Epicardial activation of the human ventricle: effects of left ventricular hypertrophy.
abstract: To determine the effects of left ventricular hypertrophy on epicardial activation of the human heart, intraoperative epicardial mapping of 40 to 66 points was performed in 10 patients undergoing aortic valve replacement. Mean calculated left ventricular mass was 364 +/- 98 g. All patients had normal left ventricular contraction. Earliest epicardial activation occurred in the anterior right ventricle in all patients. In 9 patients, it was the only epicardial breakthrough point. One patient had a single inferior left ventricular breakthrough point. Epicardial activation spread from the right ventricle towards the left ventricle in both the anterior and inferior direction. Latest epicardial activation occurred at the base of the left ventricle in 9 patients and the base of the right ventricle in 1. When compared with patients with coronary artery disease, normal ventricular contraction, and no left ventricular hypertrophy, patients with hypertrophy had fewer left ventricular breakthrough points (p less than 0.001) and were more likely to have latest activation at the left ventricular base (p less than 0.0010. We conclude that left ventricular hypertrophy is associated with marked changes in the pattern of epicardial activation. These changes may reflect delay in spread from endocardium due to the increased wall thickness.
mesh_terms: D000328:Adult; D000368:Aged; D001021:Aortic Valve; D006328:Cardiac Catheterization; D006332:Cardiomegaly / Q000175:diagnosis* / Q000503:physiopathology; D004452:Echocardiography; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction