Interpretation of electrocardiographic abnormalities in hypertrophic cardiomyopathy with cardiac magnetic resonance.

Abstract

To clarify the mechanisms of electrocardiographic abnormalities in hypertrophic cardiomyopathy, 102 patients were examined with cardiac magnetic resonance. Distribution and magnitude of hypertrophy and late-enhancement were correlated with electrocardiographic abnormalities. Abnormal Q waves were associated with greater upper anterior septal thickness (22+/-7 mm vs. 18+/-5 mm, P=0.001) and increased ratios of upper anterior septum to mean inferolateral (P=0.01), anterolateral (P=0.002), apical (P=0.001), and right ventricular (P=0.001) wall thickness. There was no relation between abnormal Q waves and late-enhancement, except for Q waves >/=40 ms (P=0.02). Conduction disturbances and absent septal Q waves were associated with late-enhancement (89 vs. 45%, P=0.01 and 75 vs. 39%, P=0.002, respectively). The depth of negative T waves was related to an increased ratio of the mean thickness between apical and basal level (P=0.01), and to the presence of apical late-enhancement (P=0.03). Abnormal Q waves reflect the interrelation between upper anterior septal thickness and other regions of the left and right ventricles, and wider Q waves are associated with late-enhancement. Conduction disturbances and absent septal Q waves are associated with late-enhancement. The depth of negative T waves is related to craniocaudal asymmetry and apical late-enhancement.