Effect of lenient versus strict rate control on cardiac remodeling in patients with atrial fibrillation data of the RACE II (RAte Control Efficacy in permanent atrial fibrillation II) study.

Objectives: The aim of this study was to evaluate echocardiographic remodeling in permanent atrial fibrillation (AF) patients treated with either lenient or strict rate control.

Background: It is unknown whether in permanent AF, lenient rate control is associated with more adverse cardiac remodeling than strict rate control.

Methods: Echocardiography was conducted at baseline and at follow-up in 517 patients included in the RACE II (RAte Control Efficacy in permanent atrial fibrillation II) trial. Echocardiographic parameters were compared between patients randomized to lenient rate control (n = 261) or strict rate control (n = 256).

Results: Baseline echocardiographic parameters were comparable between patients randomized to lenient and strict rate control. Between baseline and follow-up, significant adverse atrial or ventricular remodeling was not observed in either group. There were also no significant differences in atrial and ventricular remodeling between patients who continuously had heart rates between 80 and 110 beats/min and patients who continuously had heart rates <80 beats/min during follow-up. Lenient rate control was not independently associated with changes in echocardiographic parameters: mean adjusted effect on left atrial size was 1.6 mm (p = 0.09) and 1.1 mm on left ventricular end-diastolic diameter (p = 0.23). Instead, female sex was independently associated with adverse remodeling: mean adjusted effect on left atrial size was 2.4 mm (p = 0.02) and 6.5 mm on left ventricular end-diastolic diameter (p < 0.0001).

Conclusions: Female sex, not lenient rate control, seemed to be associated with significant adverse cardiac remodeling in patients with permanent AF such as those enrolled in the RACE II study. (RAte Control Efficacy in Permanent Atrial Fibrillation [RACE II]; NCT00392613).