β-Blockers and 1-Year Postdischarge Mortality for Heart Failure and Reduced Ejection Fraction and Slow Discharge Heart Rate

Abstract

Background Many hospitalized patients with heart failure and reduced ejection fraction ( HF r EF ) have a slow heart rate at discharge, and the effect of β-blockers may be reduced in those patients. We sought to examine the variable effect of β-blockers on clinical outcomes according to the discharge heart rate of hospitalized HF r EF patients. Methods and Results The KorAHF (Korean Acute Heart Failure) registry consecutively enrolled 5625 patients hospitalized for acute heart failure. In this analysis, we included patients with HF r EF (left ventricular ejection fraction ≤40%). Slow heart rate was defined as <70 beats per minute regardless of the use of β-blockers. The primary outcome was 1-year all-cause postdischarge death according to heart rate. Among 2932 patients with HF r EF , 840 (29%) had a slow heart rate and 56% received β-blockers at discharge. Patients with slow heart rates were older and had lower 1-year mortality than those with high heart rates ( P<0.001). A significant interaction between discharge heart rate and β-blocker use was observed ( P<0.001 for interaction). When stratified, only patients without a β-blocker prescription and with a high heart rate showed higher 1-year mortality. In a Cox-proportional hazards regression analysis, β-blocker prescription at discharge was associated with 24% reduced risk for 1-year mortality in patients with high heart rates (hazard ratio: 0.76; 95% CI, 0.61-0.95) but not in those with slow heart rates (hazard ratio: 1.02; 95% CI, 0.68-1.55). Conclusions Many patients with acute heart failure have slow discharge heart rates, and β-blockers may have a limited effect on HF r EF and slow discharge heart rate. Clinical Trial Registration URL : http://www.clinicaltrial.gov . Unique identifier: NCT 01389843.

Trial registration: ClinicalTrials.gov NCT01389843.

Keywords: heart failure; heart rate; outcome; β‐blocker.

Figure 1

The study patients. BB indicates β‐blocker; KorAHF, Korean acute heart failure; LVEF, left ventricular ejection fraction.

Figure 2

BB prescription rate and change in heart rate. A, BB prescription rate and proportion of patients with slow heart rate. B, Among patients with high heart rate, patients with BBs had lower heart rate than those without BBs (at discharge 82.7±10.8 vs 85.6±11.6 bpm, P<0.001; at 1 month: 82.8±16.7 vs 87.9±15.8 bpm, P<0.001; at 3 months: 78.0±15.5 vs 83.9±14.9 bpm, P<0.001; at 6 months: 75.6±13.9 vs 83.5±15.2 bpm, P<0.001; at 12 months: 79.0±14.4 vs 82.4±16.6 bpm, P=0.002). Among patients with slow heart rate, the heart rate did not differ after 3 months from discharge (at discharge: 62.3±5.2 vs 61.4±5.8 bpm P=0.015; at 1 month: 71.5±14.6 vs 74.5±16.6 bpm, P=0.036; at 3 months: 72.8±14.9 vs 73.0±16.9 bpm, P=0.649; at 12 months: 73.8±14.1 vs 73.5±15.4 bpm, P=0.806). BB indicates β‐blocker; bpm, beats per minute; HR, heart rate.

Figure 3

One‐year all‐cause death and hospitalization for HF according to heart rate and BB prescription at discharge. A, Only patients with high heart rate and no BB prescription at discharge had higher 1‐year all‐cause mortality, whereas there was no significant difference among the other groups. B, Patients without BB prescription had higher 1‐year hospitalization for HF regardless of heart rate, whereas those with BB prescription and slow heart rate had the lowest hospitalization. BB indicates β‐blocker; HF, heart failure.

Figure 4

One‐year all‐cause deaths in patients with sinus rhythm and atrial fibrillation. A, Sinus rhythm. B, In the subgroup of patients with atrial fibrillation, patients taking a BB at discharge had better outcomes regardless of heart rate, whereas those without a BB and with high heart rate had the worst outcomes. BB indicates β‐blocker; HR, heart rate.

Figure 5

One‐year all‐cause deaths according to BB dosage. In all patients and patients with high heart rate, patients without BB prescription at discharge had higher 1‐year all‐cause mortality than those with BB prescription; however, there was no difference in mortality between patients with BB dose above and below the median. Among patients with slow heart rate, 1‐year mortality did not differ between those with doses above and below the median and those without a BB. BB indicates β‐blocker; bpm, beats per minute; HR, heart rate.

Figure 6

Heart rate and outcomes. A, The risk of mortality increased as the heart rate elevated in patients both with and without BBs. B, Effect size of BBs on outcomes according to heart rate. The effect of BBs appeared to decrease as the heart rate declined. The solid line represents the estimated probability of 1‐year all‐cause mortality, the shaded area is 95% CI. Below is a density plot showing the distribution of observed heart rate. BB indicates β‐blocker.