Get access

Prognostic Value of QT/RR Slope in Predicting Mortality in Patients with Congestive Heart Failure

Authors


  • Funding for this study was provided by a grant from the Instituto de Salud Carlos III, Madrid, Spain (grant code: G03/078).

  • Manuscript received 18 February 2008; Revised manuscript received 14 March 2008; Accepted for publication 24 March 2008.

Address for correspondence: Iwona Cygankiewicz, M.D, Ph.D., Heart Research Follow-up Program, Cardiology Division, University of Rochester Medical Center, 601 Elmwood Ave., Box 653, Rochester, NY 14642, USA. Fax: 585-273-5283; E-mail: iwona.cygankiewicz@heart.rochester.edu

Abstract

Introduction: Repolarization dynamics, reflecting adaptation of QT to changing heart rate, is considered a marker of unfavorable prognosis in patients with heart diseases. We aimed to evaluate the prognostic value of QT/RR slope in predicting total mortality (TM) and sudden death (SD) in patients with congestive heart failure (CHF).

Methods and Results: In 651 sinus rhythm patients with CHF in NYHA class II–III enrolled in the MUSIC study, 24-hour Holter monitoring was performed at enrollment to assess slope of the QTa/RR (QT apex) and QTe/RR (QTend) during the entire 24-hour Holter recording and separately during day and night periods. Patients were followed for a median of 44 months, with the primary endpoint defined as TM and the secondary as SD. Analysis of repolarization dynamics was feasible in 542 patients (407M), mean age 63 years, 83% in NYHA class II, 49% with ischemic cardiomyopathy, with mean LVEF 37%. Mean value of QTa/RR slope was 0.172 and QTe/RR was 0.193. During the 44-month follow-up there were 119 deaths including 47 SD. Nonsurvivors were characterized by steeper QT/RR slopes. Increased QT/RR slopes during the daytime (>0.20 for QTa and >0.22 for QTe) were independently associated with increased TM in multivariate analysis after adjustment for clinical covariates with respective hazard ratios 1.57 and 1.58, P = 0.002. None of the dynamic repolarization parameters was associated with increased risk of SD in the entire population.

Conclusions: Abnormal repolarization dynamics reflected as increased daytime QT/RR slopes is an independent risk stratifier of all-cause mortality in patients with chronic heart failure

Ancillary