DDD versus VVIR versus VVI mode in patients with indication to dual-chamber stimulation: a prospective, randomized, controlled, single-blind study.

Background: The aim of this study was to compare VVI, VVIR and DDD modes in patients with indication to dual-chamber stimulation, depending on left ventricular function.
Methods: Two groups of patients were implanted with a DDD pacemaker: Group I with ejection fraction > 40% and Group II with ejection fraction < 40%. Patients with a history of atrial arrhythmia or retrograde conduction were excluded. At follow-up (1 month each) quality of life (QoL), patient preference and echo parameters were collected. At hospital discharge all patients were programmed in DDD for 1 month and then randomized to VVI or VVIR mode. At the end of the period in VVI or VVIR mode each patient underwent a control period in DDD and then was programmed in VVIR or VVI mode.
Results: Seventeen patients out of 23 preferred DDD mode and 6 did not perceive any subjective difference among DDD, VVI and VVIR modes (4/9 in Group I and 2/14 in Group II, p = 0.0017). QoL was significantly different between the two groups and at each follow-up showed the best values in DDD. The correlation between QoL and Tei index was 0.62 in Group I (p < 0.001) and 0.35 in Group II (p = 0.001). Neither ejection fraction nor fractional shortening showed any significant difference during the three phases of the study.
Conclusions: Most patients preferred the DDD mode. The Tei index showed a good correlation with QoL and both QoL and Tei index significantly improved with DDD mode as compared to VVI and VVIR.