Successful treatment of functional mitral regurgitation in severe heart failure with atrial pacing: A case report

Functional mitral regurgitation (MR) is a common complication accompanying left ventricular dysfunction. Increasing resting heart rate (HR) is demonstrated to be associated with increased mortality in heart failure (HF) patients. Thus, lowering HR is recommended by recent HF management guidelines. However, the hemodynamic effect of changing HR on functional MR remains unclear. We present a patient who demonstrated ischemic cardiomyopathy and was admitted to our hospital. Electrocardiogram showed complete left bundle block with QRS interval of 120 ms and HR of 60 beats/min. Temporal pacing study was performed to confirm the efficacy of cardiac resynchronization therapy. Functional MR was unexpectedly improved by increasing HR with atrial pacing rather than biventricular pacing. Brain natriuretic peptide was reduced from 3642 pg/ml to 435 pg/ml after 2 weeks. Our case indicates that in some HF patients with functional MR, a prolonged diastolic interval may lead to deteriorating MR flow.70 beats/min is observed in patients with systolic HF in sinus rhythm, lowering the HR below 70 beats/min is recommended according to the recent guidelines. However, in some HF patients with functional MR, it is possible that a prolonged diastolic interval leads to deterioration in regurgitation flow. Increasing the HR by atrial pacing may provide a favorable outcome in such patients.>