Possible association of papillary muscle hypertrophy with the genesis of J-waves

Background: Although J-waves have been known to be associated with vulnerability to ventricular fibrillation, their electrophysiologic mechanism remains to be elucidated. The papillary muscles (PMs) of the left ventricle (LV) have been recognized as the target site of radiofrequency ablation for ventricular arrhythmias. However, the relationship between PM hypertrophy and J-waves has not been investigated. Objective: To investigate the electrocardiographic characteristics, including the J-waves, in patients with solitary PM hypertrophy. Methods: We studied 101 patients with PM hypertrophy without LV hypertrophy (PMH group) and 159 age- and sex-matched control subjects (control group). The parameters of the 12-lead electrocardiogram and the echocardiogram were compared between the two groups. Results: Compared with the control group, the PMH group had significantly higher incidence (15% vs. 33%, p = 0.001) and amplitude (0.17 +/- 0.06 mV vs. 0.28 +/- 0.17 mV, p < 0.01) of J-waves; significantly longer QRS, QTc, and JTc intervals (p = 0.0001, p < 0.0001, and p < 0.05, respectively); significantly greater Sokolow-Lyon index (p < 0.001); and significantly greater LV wall thickness and LV mass index (p < 0.0001 for each). Multivariate logistic regression analysis showed that only the PM hypertrophy was an independent predictor of the presence of J-waves. Conclusion: PM hypertrophy was related to the genesis of J-waves. (C) 2019 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.