Characteristics of QT interval dynamicity in patients with heart failure / 心血管康复医学杂志

ABSTRACT

Objective: To study the characteristics of QT interval dynamicity in patients with heart failure (HF) and provide reference for predicting risk of sudden death in HF patients. Methods: A total of 80 inpatients with chronic HF from our department of cardiology were selected as HF group, and another 50 healthy volunteers were enrolled as healthy control group. All subjects received 24h ambulatory electrocardiography (ECG), surface ECG and echocardiography examination. Left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), QT dispersion (QTd), index for heart rate variability-- standard deviation of normal to normal RR intervals calculated over the 24 h period (SDNN) and slope of QT/RR correlated linear were measured. Results: Compared with healthy control group, there were significant increase in LVESV [(34.0±8.3) ml vs. (90.4±15.4) ml], LVEDV [(86.0±32.2) ml vs. (150.3±30.4) ml], QTd [（35.6±8.5）ms vs.（46.6±10.4）ms], slopes of QTe /RR [(0.136±0.021) vs. (0.175±0.023)] and QTp/RR [(0.130±0.026) vs. (0.158± 0.033)], and significant decrease in LVEF [(60.6±8.4) % vs. (38.5±8.8) %], and SDNN [（140.3±53.3）ms vs.（100.4±40.3）ms] in HF group, P<0.01 all.. Conclusions: Instability of ventricular repolarization in patients with heart failure makes their QT/RR slope significantly higher than that of normal subjects.