Abstract
Prognostic impact of heart rate reduction therapy using ivabradine, a selective inhibitor of I(f) channel that purely reduces heart rate, in patients with heart failure with reduced ejection fraction and sinus tachycardia has been demonstrated. However, ideal heart rate remains unknown. We experienced an 80-year-old woman with reduced left ventricular ejection fraction who was hospitalized due to congestive heart failure. Following the ivabradine administration that decreased her heart rate from 100 bpm down to around 60 bpm, the "overlap" between E-wave and A-wave in the trans-mitral Doppler echocardiography diminished, accompanied by an improvement in cardiac output. Heart rate optimization targeting to diminish the overlap between E-wave and A-wave might maximize cardiac output and improve the clinical course via facilitated cardiac reverse remodeling. Further studies are warranted to validate the implication of therapeutic strategy to aggressively minimize the echocardiographic "overlap" by heart rate reduction therapy in heart failure patients.