Importance of baseline heart rate as a predictor of cardiac functional recovery in newly diagnosed heart failure with reduced ejection fraction.

BACKGROUND: Left ventricular ejection fraction (LVEF) has shown to predict outcomes in patients with heart failure (HF). Left ventricular recovery (LVR) has shown to improve prognosis. HYPOTHESIS: Guideline-directed medical therapy will predict LVR in patients with HF and reduced LVEF.
METHODS: We studied 244 patients with newly diagnosed HF and an LVEF ≤35%. LVR was defined as an increase in LVEF ≥40%. Patients who experienced LVR were compared with those who had persistent left ventricular dysfunction.
RESULTS: Population characteristics included ischemic etiology, 38.1%; baseline LVEF, 23% ±6%; and mean baseline heart rate (HR), 75 ±13 bpm. Guideline-directed medical therapy was achieved as follows: angiotensin-converting enzyme inhibitors, 74.3%; β-blockers (BB), 95.4%; target dosing of angiotensin-converting enzyme inhibitors, 33.7%; target dosing of BB, 40.2%. LVR occurred in 154/244 patients (63.1%). By multivariable analysis, baseline HR ≤70 bpm was the only independent predictor of LVR (odds ratio: 3.39, 95% confidence interval: 1.5-7.5, P = 0.003). Target dosing of BB therapy was predictive of LVR only in the univariate analysis (odds ratio: 1.9, 95% confidence interval: 1.1-3.4, P = 0.03). Furthermore, the composite endpoint of HF hospitalization or mortality occurred less frequently in those who did vs those who did not achieve target BB doses (5.4% vs 16.7%, respectively; P = 0.023).
CONCLUSIONS: The novel findings of our analysis reveal that the only predictor of LVR in this study was a low baseline HR. Early modulation of HR in newly diagnosed HF patients may increase the rates of LVR.