DDDR cardiac pacemakers meet the demand of the two main goals of modern cardiac pacing enauring both the synchronization of atriums and ventricles and the frequency response to physical exercise. In this way they simulate the normal heart rhythm behaviour best of all pacemakers in use. Since 1992 through 1995 the DDDR pacemakers were implanted in 27 patients aged 20-79 (mean 59.9) years in our pacemaker centre. The follow-up period has amounted to 46 months. 26 patients suffered from advanced sinus syndrome with the chronotropic incompetence and with the atrioventricular block, the remaining young man was given the pacemaker because of congenital atrioventricular block. In one patient epicardial leads implanted by thoracotomy have been used. After the wound had healed and the pulse energy had been reduced, the pacemaker bearers underwent the stepwise symptoms limited bicycle or treadmill stress test. During the follow-up the incidence of particular complications was assessed. In comparison with the DDD mode without the sensor, the DDDR pacemakers exhibiting the rate adaptation did improve the working capacity in particular patients in the stress test. (Tab. 1, Fig. 5, Ref. 16).

2 interní klinika Lékarské fakulty University Karlovy a Vseobecné fakultní nemocnice v Prahe Ceská republika