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The effects of pacing mode on development of chronic AF in patients undergoing pacemaker implantation due to AV block : A retrospective study

Permanent atrial fibrillation (AF) is the most prevalent arrhythmia among elderly patients. Permanent AF may cause thromboembolic events, heart failure, poor quality of life and recurrent hospitalizations. The effects of pacemaker mode on developing permanent AF have been investigated in several studies. In this study, we aimed to investigate the effects of physiological pacing (DDD) and non-physiological pacing (VVI) on the development of permanent AF in patients undergoing pacemaker implantation due to AV block who initially had a sinus rhythm and did not have significant coronary artery disease (CAD). We included 148 patients who underwent permanent cardiac pacemaker implantation (67 VVI and 81 DDD) due to AV block. All patients had P wave activity before pacemaker insertion, and none had significant CAD on coronary angiography. Trans thoracic echocardiography and a 12 lead ECG of each patient were performed. Of 148 patients who were included in the study, 81 had DDD pacemaker and 67 had VVI pacemaker. There were 72 women (48.6%) and 76 men (51.4%). The mean age was 67±7 years. Mean follow-up time was 5.7±1.8 years. Permanent AF developed in 16 (10.8%) patients. Age, gender, hypertension, diabetes mellitus, initial LA diameter, and LV ejection fraction were not statistically the difference between two groups. Pacemaker mode was the unique variable that reached statistical significance (p=0.003). Permanent AF developed in 13 (19.4%) patients and in 3 (3.7%) patients in VVI and DDD pacemaker groups, respectively (p=0.003). The comparison of initial and follow-up echocardiographic parameters such as change in LA diameters, LV ejection fractions, and LV end-systolic and end-diastolic diameters revealed that merely the change in LA diameters was statistically significant between the patients who developed permanent AF and who did not. In this study, we found that pacemaker mode significantly leads to the development of permanent AF. The risk of developing permanent AF was 7-8 times greater in the VVI group than that in the DDD group. Neither mode had effects on ventricular systolic functions. However, the mean left atrial diameter was significantly higher in the VVI group. According to these results, we suggest the insertion of a DDD pacemaker for the patient with P wave activity and AV block.