Abstract
The effects of terminating imposed rapid rate driving through an artificial pacemaker were studied in 18 patients with complete A-V block.
Post-drive depression of pacemakers and the resulting deceleration of the heart is observed in almost all cases. Idioventricular pacemakers showed much depression following imposed ventricular drive than did A-V nodal pacemaker. The max. recovery time after drive in H-V block reached 10sec. or more. In some cases entrance and exit block of latent pacemakers were observed. Atropine does not abolish the post-drive depression. From these results it is concluded that, in patients with complete A-V block, frequency-dependent inhibition is important for the analysis of the functional specificity of atrioventricular b-lock, when latent ventricular pacemaker will have to activate the ventricles.
