Prognostic Implications of Mitral Valve Inflow Pattern Overlap during Ivabradine Therapy

The prognostic impact of mitral inflow wave overlap during ivabradine therapy in patients with heart failure with reduced ejection fraction (HFrEF) remains to be unknown. Thus, in this study, we have retrospectively examined consecutive inpatients with HFrEF admitted with decompensated heart failure who continued ivabradine following the index discharge. Ideal heart rate (HR), at which echocardiographic mitral inflow wave overlap is theoretically 0, was retrospectively calculated as follows: 96 - 0.13 x (deceleration time [msec]). HR difference was then calculated as follows: actual HR - ideal HR. The association between the HR difference at index discharge and a composite outcome of cardiovascular death and heart failure readmissions was investigated. In total, 16 patients (68 [47, 75] years old, 11 men, median left ventricular ejection fraction 28% [22%, 35%]) were included in this study for analysis. Baseline actual IIR was determined to be 88 (81, 93) bpm, whereas the ideal HR was calculated as 75 (73, 76) bpm. Following the initiation of ivabradine, actual HR at index discharge was 75 (64, 84) bpm. Patients with optimal HR (actual HR - ideal HR < +/- 10 bpm; n = 9) were found to have experienced a lower incidence of the composite endpoint (40% versus 100%, P = 0.013) compared with those with sub-optimal HR (n = 7) with a hazard ratio of 0.10 (95% confidence interval 0.01-0.91) adjusted for actual IIR at index discharge. In conclusion, IIR modulation therapy using ivabradine may improve outcomes in patients with HFrEF if individualized ideal HR was achieved.