The effect of ivabradine treatment on atrial conduction times in patients with chronic heart failure

Aim: HR reduction with ivabradine improves left ventricle filling by the prolongation of the diastolic time and increases stroke volume. However, it remains unclear what ivabradine's effect is on atrial conduction time and mechanical atrial function. The aim of our study was to evaluate in stable outpatients with systolic HF the short-term (3 months) effect of ivabradine on atrail conduction time and mechanical function. Method: This study population consists of outpatients who came to the Cardiology Clinic of Abant Izzet Baysal University Hospital. Patients were recruited if they were men or women with more than 18 years of age with a established diagnosis of stable heart failure (HF) with reduced left ventricular ejection fraction (≤35%) in New York Heart Association functional classes II to III and at least 5 minutes after resting 12-lead electrocardiogram (ECG) as measured by the baseline heart rate per minute to 70 beats/min or higher. We evaluated prospectively 43 (34 males, 9 females) patients with HF. Before and after treatment all patients were evaluated by transthoracic M mode, two dimensional (2D), pulsed-wave (PW), continuous wave (CW), color flow and tissue Doppler imaging (TDI). Before and after treatment LA volumes were measured using the biplane area length method and LA active and passive emptying volumes and fraction were calculated. Intra- and interatrial electromechanical delay (EMD) were measured by tissue Doppler imaging (TDI). Results: 33 men and 9 women with mean ± SD age of 64.7 ± 9.9 years were included in this study. All patients were in the NYHA class II and III and resting heart rates were 84.4 ± 12.2 bpm on average with sinus rhythm. Vmax and Vp were significantly reduced after ivabradine treatment (94.6 ± 37.7, 85.9 ± 28.6, p = 0.04, 75.6 ± 34.3, 67.7 ± 28.6, p = 0.012). Also, left atrial active emptying fraction significantly reduced after treatment (22.4 ± 10.6, 17.6 ± 9.1, p= 0.03). Interatrial electromechanical delay interval (PA lateral-PA tricuspit) was significantly reduced after ivabradine treatment (33.7 ± 12.7, 26.2 ± 10.1 , p = 0.001). Conclusion: Our study demonstrated that, atrial conduction time was significantly abbreviated and mechanical atrial functions were considerably improved after 3 months ivabradine treatment.