Use of atrial and bifocal cardiac pacemakers for treating resistant dysrhythmias.

Several permanent cardiac pacing techniques have been utilized to control resistant cardiac arrhythmias. SA block, sinus arrest and intermittent ventricular tachycardia was controlled by the use of an atrial 'J' catheter and a rate programmable demand pacemaker. When these arrhythmias were associated with AV conduction delay they were managed with an AV sequential pacemaker with the additional insertion of a ventricular pacing lead. Appropriate adjustment of the AV sequential interval inhibited reciprocal AV or VA reentry thus controlling reciprocal tachycardia. Frequent ventricular premature systoles or intermittent ventricular tachycardia with in appropriately delayed sinus or subsidiary escape cycle lengths appear best managed by an AV sequential pacemaker by adjusting the atrial return cycle. Intractable atrial reentry tachycardias appear best managed by paired or rapid atrial stimulating pacemakers. Development of variable atrial rate, AV sequential and atrial return cycle activating pacemakers offer an effective control of resistant cardiac arrhythmias.