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

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)