Improvement of increased cQTd is associated with heart function in patients with ischemic heart failure

BACKGROUND: Chronic heart failure (CHF) is life-threatening without timely or effective intervention. In this study, we investigated the association between QT dispersion corrected for heart rate (cQTd) and heart function in patients with CHF. METHODS: From January 2013 to December 2015, we continuously enrolled 240 patients categorized as New York Heart Association functional class (NYHA) III–IV with a left ventricular ejection fraction (LVEF) < 40%. Based on the etiology, the patients were divided into a dilated cardiomyopathy (DCM) group (n = 120) and an ischemic cardiomyopathy (ICM) group (n = 120). Then, based on the cQTd width, the ICM group was divided into two subgroups: a QS group (cQTd ≤ 60 ms, n = 70) and a QL group (cQTd > 60 ms, n = 50). All patients were examined by echocardiography and 12-lead electrocardiography (ECG) at 1, 3, 6, and 12 months after enrollment. RESULTS: After one year of optimized medical treatment, patients in both groups showed significant improvement in LVEF and NYHA classification from baseline. However, the cQTd in the ICM group, especially the QL, was significantly shorter than that in the DCM group at each time point. In addition, the cQTd was negatively correlated with LVEF and 6-min walking test and positively correlated with NYHA class in the ICM group. CONCLUSIONS: The present findings clearly demonstrate that cQTd is a meaningful parameter for assessing heart function in the follow-up of ICM patients.