Purpose: Elevated heart rate (70 beats per minute-bpm or more) is a predictor of impaired prognosis in patients with ischemic heart failure. The Austrian Working Group on Heart Failure has established a registry in May 2006 for all patients referred to dedicated heart failure clinics with a planned follow-up after 12 ± 3 months. Here we report an analysis of the prognostic impact of elevated heart rate at referral in a well-defined cohort of heart failure patients.
Methods: Between May 2006 and October 2009 1904 patients have been documented in the Austrian Heart Failure Registry. One thousand threehundred and sixty three patients (72%) had sinus rhythm at referral. Kaplan-Meier and Cox proportional hazards regression analyses were used to compare overall and cardiovascular mortality between high (70 bpm or more) and low heart-rate groups. Patients who were lost-to-follow-up (n = 166) were censored at the time of last contact.
Results: At baseline in 793 patients (58%) heart rate has been elevated (70 bpm or more) while in 562 patients it has been below 70 bpm, in 8 patients no baseline heart rate has been recorded. Groups were equally balanced regarding age, gender and cardiovascular risk factors with the exception of smokers (more active smokers in the high heart-rate group: 23 vs 14%; p = 0.001) and valvular cause of heart failure (more frequent in the high heart-rate group: 3% vs 1%; p = 0.012). Patients in the high heart-rate group had significantly higher median NT-pro-BNP (1470 pg/ml, IQR 499-4188 pg/ml) compared to patients in the low heart-rate group (784 pg/ml, IQR 314-2162 pg/ml; p < 0.001). NYHA functional classes III and IV have been more frequent in the high heart-rate group than in the low heart-rate group (32% and 22%, respectively; p < 0.001) while reduced left ventricular ejection fraction (39% or less) has been more frequent in the high heart-rate group than in the low heart-rate group (71% and 61%, respectively; p < 0.001). In the high heart-rate group treatment with beta-blockers has been less frequent than in the low heart rate group (76% and 86%, respectively; p < 0.01) while dosage of beta-blocker therapy has been comparable in both groups. Of the 75 patients who died within 3.5 years 38 deaths had a cardiovascular cause. Cox proportional hazards analysis revealed that high NYHA functional class (III and IV) and elevated heart rate (70 bpm or more) were the best predictors of overall mortality while cardiovascular mortality could best be predicted by NYHA functional classes III and IV.
Conclusion: Higher NYHA-functional classes and elevated heart rate are predictors of adverse outcome in chronic heart failure patients.