Aims: 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. Methods and results: 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). Conclusion: 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. Aims: 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. Methods and results: 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 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 (P = 0.01 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 levels to the presence of apical late-enhancem ent (P = 0.03). Conclusion: 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 depth-enhancement. The depth of negative T waves is related to craniocaudal asymmetry and apical late-enhancement.