Does a prolonged QTc interval predict mortality in patients with heart failure and BNP levels >400 pg/mL?
A prolonged QTc interval (>440 ms) is a strong, independent predictor of mortality in patients with advanced heart failure and elevated BNP levels.
BACKGROUND: The role of QTc interval prolongation in heart failure remains poorly defined. To better understand it, we analyzed the QTc interval duration in patients with heart failure with high B-type natriuretic peptide (BNP) levels and analyzed the combined prognostic impact of prolonged QTc and elevated BNP. METHODS AND RESULTS: QTc intervals were measured in 241 patients with heart failure who had BNP levels >400 pg/mL. QT interval duration was determined by averaging 3 consecutive beats through leads II and V4 on a standard 12-lead ECG and corrected by using the Bazett formula. QTc intervals were prolonged (>440 ms) in 122 (51%) patients and normal in 119 (49%). The BNP levels in these 2 groups were not significantly different (786+/-321 pg/mL in the prolonged QTc group versus 733+/-274 pg/mL in the normal QTc group, P=0.13). During 6 months of follow-up, 46 patients died, 9 underwent transplantation, and 17 underwent left ventricular assist device implantation. The deaths were attributed to pump failure (n=24, 52%), sudden cardiac death (n=18, 39%), or noncardiac causes (n=4, 9%). Kaplan-Meier survival rates were 3 times higher in the normal QTc group than in the prolonged QTc group (P400 pg/mL.
Vrtovec et al. (Tue,) studied this question.