Efficacy of Ivabradine in Patient With Both Persistent Atrial Fibrillation and Heart Failure With Reduce Ejection Fraction

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Previous studies have shown that rate control strategy in AF is non-inferior to rhythm control strategy, in terms of stroke and mortality risk. In addition, rate control strategy is associated with lower risk of hospitalization and non-cardiovascular mortality. Therefore, rate control is an essential strategy to improve quality of life, decrease morbidity and prevent tachycardia-induced cardiomyopathy in AF patients. The recommended rate control agents include beta-blocker, nondihydropyridine calcium-channel blocker (CCB), digoxin and amiodarone. However, in heart failure with reduced ejection fraction patient, the medication of rate control were beta-blocker than digoxin. But several clinical observation study show excess mortality in AF patients. Ivabradine, a If inhibitor, it is well-established that a pacemaker current, If current, is functionally expressed in the sinus node . Previous studies have shown that Ivabradine, If inhibitor, significantly reduces sinus rate and improves prognosis in patients with systolic heart failure. Interestingly, several investigators found that hyperpolarization- activated cyclic nucleotidylated channel 4 current (HCN4), the main isoform of the channel responsible for If current, is also functionally expressed in the Atrioventricular node(AV node). Recent data have shown that inhibition of If current slows AV node conduction in animals and humans. Thus, we want to compare the effect of Ivabradine on ventricular rate with digoxin in this study.