[Experience with VVI, QT time and activity-controlled pacemaker systems in patients with tranvenous ablation of atrioventricular conduction].

In 36 patients with atrial flutter, atrial fibrillation or supraventricular tachycardia, refractory to medical treatment, who underwent interruption of atrioventricular conduction by means of an electrode-catheter, i.e. His bundle ablation, various pacemakers were studied. In 22 patients (group I) a heart rate programmable VVI-pacemaker was implanted, in 7 patients (group II) an activity-mode pacemaker (Activitrax 8400, Fa. Medtronic) and in 7 patients (group III) a QT-mode pacemaker (Quintech 911, Fa. Vitatron). To study physical work capacity, exercise testing was performed using a bicycle ergometer in group I and group III and a treadmill in group II. Sixteen patients with VVI-mode pacing (72.7%) complained of shortness of breath during exercise in normal daily life, in comparison to only 2 patients in group II (28.6%) and 3 patients in group III (42.9%). The exercise test revealed a normal physical work capacity in only 3 out of 22 patients (13.6%) with a VVI-pacemaker, but a normal physical work capacity in all patients with activity-mode or QT-mode pacing. Heart rate during stress test in patients with an Activitrax-pacemaker increased more rapidly than in patients with a Quintech-pacemaker and also dropped more quickly in the Activitrax-group than in the Quintech-group after cessation of the stress test. It is important to note that pacemaker reprogramming was necessary in 1 out of 7 patients (14.3%) with activity-mode pacing and in 4 out of 7 patients (57.1%) with QT-mode pacing.(ABSTRACT TRUNCATED AT 250 WORDS)