Differential Effectiveness of Landiolol Between Atrial Fibrillation and Atrial Flutter/Atrial Tachycardia Patients With Left Ventricular Dysfunction

Background: Landiolol, an ultra-short acting beta(1)-selective blocker, is more effective for controlling the heart rate (HR) than digoxin in patients with atrial tachyarrhythmias and left ventricular (LV) dysfunction. The impact of the type of atrial tachyarrhythmias on the effectiveness of landiolol is uncertain. We evaluated the efficacy and safety of landiolol on tachycardiac atrial fibrillation (AF) and tachycardiac atrial flutter/atrial tachycardia (AFl/AT) in patients with reduced LV function. Methods and Results: Seventy-seven patients treated with landiolol were retrospectively analyzed. There were no significant differences in the baseline characteristics between the AF group (n=65) and AFl/AT group (n=12). Despite a higher dosage, the %change in HR from baseline to 12 and 24 h was only -10.2 +/- 12.7% and -16.1 +/- 19.4% in the AFl/AT group, while it was -28.3 +/- 13.2% and -31.3 +/- 11.3% in the AF group (P<0.02), respectively. The prevalence of the responders to landiolol treatment was much greater in the AF group than in the AFl/AT group (P<0.001). Alternative treatments such as i.v. amiodarone and electrical cardioversion were required in 83% of the AFl/AT patients. Conclusions: Landiolol was ineffective in the majority of AFl/AT patients. An alternative management to prevent any worsening of heart failure might be considered in those patients.