[Atrial-triggered and ventricular-inhibited ventricular VDD pacing with atrial and ventricular single catheter electrodes--the Phymos MPS pacemaker].

Optimal treatment from the haemodynamic aspect in complete atrioventricular block is dual-chamber DDD pacing. It makes possible atrioventricular sequence and adaptability of the frequency of ventricular pacing to the load under the control of the sinoatrial node. DDD pacing calls, however, for an atrial and ventricular electrode on two leads. Italian authors developed in 1984 a pacemaker (PM) PHYMOS (MEDICO ITALIA) which makes possible atrial triggered ventricular VDD pacing by means of a single pass lead with a tripolar electrode. As the first ones in the post-communist countries the authors implanted to six patients a PM PHYMOS MPS. They confirmed that the advantages of the VDD system, as compared with DDD, are the use of a single pass lead. This makes the implantation quicker, simpler and safer and reduces the time of X-ray irradiation and the incidence of electrodes dislocations. Another advantage is the lower incidence of atrial fibrillation and probably also pacemaker mediated tachycardias. The disadvantages of the VDD system are that atrial stimulation is impossible and that the diameter of the single pass lead is somewhat larger. According to data in the literature and the so far small experience of the authors, when the indication is correct--atrioventricular block grade III or II with intact function of the sinoatrial node--the advantages of VDD pacing with a single pass lead, as compared with DDD pacing, predominate over disadvantages.