PERMANENT CARDIAC PACING AND THROMBOEMBOLIC RISK IN ELDERLY PATIENTS

In patients undergoing permanent cardiac pacing, the maintenance of at rial contractility is important to ensure adequate ventricular filling and to guarantee an optimal ventricular ejection capacity. The approp riate pacing mode, assuring a suitable mechanical atrioventricular cou pling, prevents the onset of atrial fibrillation and contributes to re duction of the risk of subsequent systemic and pulmonary thromboemboli c episodes. We examined 461 patients (266 males and 195 females, aged between 52 and 97 years, average age 76.5 +/- 18) paced for conduction disturbances of various degrees and etiology. Of them, 323 patients r eceived ventricular demand pacemaker (VVI group, average age 77.9 year s); 138 underwent dual chamber pacing (DCP group, average age 75.2 yea rs), 117 of the latter received universal demand pacing (DDD) and 21 a trial synchronous ventricular demand pacing (VDD). The patients were s ubsequently divided into two age-groups: Group A (less than or equal t o 75 years, 174 patients), and Group B (greater than or equal to 75 ye ars, 287 patients). According to pacing mode and successive developmen t of stable atrial fibrillation (AF), we analysed the occurrence of sy stemic and/or pulmonary thromboembolic episodes and the incidence of f atal events. During our study, performed from January 1986 to August 1 993, 70 embolic episodes were observed in the VVI group and six in the DCP group. Eighty-four patients with VVI units developed AF during fo llow-up, compared with only five patients in the DCP group. Our data i ndicate that VVI patients have a higher incidence of AF, embolic compl ications and cerebrovascular mortality, in comparison with the DCP gro up. VVI pacing should be avoided, especially in older patients, when a trial rhythmical activity is present.