Abstract 14025: Mild QTc Prolongation was Associated With Cardiovascular Events in Japanese Male Patients With Cardiovascular Risk Japan Morning Surge Home Blood Pressure (J-HOP) Study

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Introduction: The relationships between QTc intervals and the risk of cardiovascular (CV) events could differ among ethnicities or between subjects with/without left ventricular hypertrophy (LVH). Hypothesis: We hypothesized that mild QTc prolongation was associated with CV events in Japanese patients with CV risk factors. Methods: Subjects were 3,592 patients enrolled in the Japan Morning Surge Home Blood Pressure Study who had one or more CV risk factors. Corrected QT intervals (QTc) were calculated using the Bazett formula. Prolonged QTc interval was defined as ≥440 ms in men and ≥460 ms in women on electrocardiogram (ECG). We divided patients into 3 subgroups according to the percentile of QTc (shortest 10%, middle 80%, and longest 10%). The primary endpoints were fatal/nonfatal CV events (myocardial infarction, stroke, hospitalization for heart failure, aortic dissection). The Sokolow-Lyon criteria (RV5(6)+SV1) ≥35 mm were used to diagnose LVH. Results: During the mean follow-up period of 48±39 months, there were 138 CV events. In male patients, those with prolonged QTc (N=57) were more likely to suffer CV events than those without prolonged QTc (N=1523) (log rank 6.22, p=0.013). A Cox proportional hazards model including age, hypertension, dyslipidemia and diabetes revealed that prolonged QTc was a significant independent predictor of CV events in male patients (hazard ratio 2.21, 95%CI 1.01-4.82, p=0.047). In female patients, CV events were similar in prolonged QTc (N=33) and non- prolonged QTc patients (N=1766, p=0.73). In male patients, the longest 10% of QTc patients (QTc≥406ms, N=157) were more likely to suffer CV events than those in the middle 80% of QTc patients (QTc 332-405ms, N=1265) and shortest 10% of QTc patients (QTc<332ms, N=157) (log rank 16.57, p<0.001). In the absence of LVH (N=1308), male patients in longest 10% of QTc suffered more CV events than those in the other groups (log rank 6.61, p=0.037), and in the presence of LVH (N=272), males in the longest 10% of QTc also suffered more CV events than those in the other groups (log rank 13.73, p=0.001).In female patients, CV events were similar in three subgroups. Conclusions: Mild QTc prolongation was associated with CV events in Japanese male patients with a CV risk with or without ECG-LVH.