Predictors of inappropriate atrial sensing in long-term VDD-pacing systems

The efficacy and stability of the atrial electrode sensing function is essential for maintaining atrioventricular (AV) synchrony. This study aimed to explore the long-term reliability and causes of the long-term sensing failure of VDD systems. We enrolled all the patients with complete or high-degree AV block who received VDD pacemakers between August 1994 to January 2006 and who were followed up for more than 12 months. The interrogation parameters, including the atrial potentials (APs) and AV-synchrony ratio were acquired immediately post-implantation and at 3-6 month intervals thereafter. An inappropriate atrial sensing efficacy was defined as an AV-synchrony ratio of < 90%. Totally 157 patients (70 +/- 12 years, 103 males) were enrolled into the study with a follow-up for 4.9 +/- 2.5 years. Twenty-six patients (16.6%) suffered from inappropriate atrial sensing. According to a Kaplan-Meier analysis, the incidence of inappropriate atrial sensing was higher in the patients with an age >= 72 years old (P = 0.047), mean AP during the implantation of < 3.0 mV (P = 0.015), concomitant use of non-dihydropyridine calcium channel blockers (CCBs) (P = 0.003), and atrial fibrillation (AF) (P < 0.001). A Cox regression analysis showed that non-dihydropyridine CCBs (hazard ratio, 3.255; 95% confidence interval, 1.148-9.227, P = 0.026) and AF (hazard ratio, 6.507; 95% confidence interval, 2.478-17.104, P < 0.001) predicted inappropriate atrial sensing. VDD pacing is a reliable pacing modality. However, we should monitor the pacemaker sensing function in the patients with the concomitant use of non-dihydropyridine CCBs and AF.