Background: There have been conflicting results about the role of strict rate control on cardiovascular outcomes in patients with chronic atrial fibrillation (AF). To date, large clinical studies have not shown a net clinical benefit derived from the current trend to specify the target ventricular rate according to the patient’s own clinical and laboratory characteristics. Although the existing literature shows no superiority of strict rate control in clinical end points, it is difficult to assess the pure rate effect without commonly coexisting medication side effects which can also influence clinical end points.

Aim: To determine the effects of strict rate control in patients with chronic AF, regarding objective parameters such as echocardiographic data and B-type natriuretic peptide (BNP) values.

Methods: 38 patients with chronic AF for whom strict rate control had been planned were enrolled in the study. Patients’ echocardiographic parameters, BNP values and 24 h Holter electrocardiography findings showing the average heart rate (HR), were studied at baseline and then monthly, until the end of the 3rd month. Patients’ negative dromotropic therapy was adjusted to achieve a target resting HR of below 80 bpm. Laboratory and echocardiographic parameters at baseline and at the end of the study were compared in the whole study group. The whole study group was subclassified according to the average resting HRs achieved, (group 1 with strict rate control < 80 bpm; n = 25, and group 2 without strict rate control; n = 13).

Results: In group 1, the average HR declined from 101 ± 16.3 bpm to 77 ± 5.2 bpm. In group 2, the average HR was 96.6 ± 6.8 bpm at baseline and there was no significant change at the end of the study (94.2 ± 5.9 bpm). In group 1, there were significant decreases in BNP, left ventricular volumes, left atrial and right atrial areas at the end of the study. In group 2, BNP values were significantly higher at the end of the study despite similar ventricular and atrial dimensions according to the baseline. Diastolic functions were assessed roughly by septal E/e’, but no significant change was observed in either group.

Conclusions: Strict rate control in patients with chronic AF yielded a significant decrease in BNP values as well as a reductionin volumes of cardiac chambers.