(1) Background: Cardiac resynchronization therapy (CRT) systems can be simplified by excluding the atrial lead and using a Ventricular-Dual-Dual (VDD) pacing lead. Possible disadvantages might include atrial undersensing and Ventricular-Ventricular-Inhibition (VVI) pacing. Because literature data concerning these systems are scarce, we analyzed their benefits and technical safety. (2) Methods: this retrospective study compared 50 patients implanted with VDD-CRT systems (group A), mainly because of unfavorable venous anatomy concerning the complication rate, with 103 subjects with Dual-Dual-Dual (DDD)-CRT systems (group B) implanted during 2000-2016 and 49 (group C) during 2016-2020. To analyze the functional parameters of the devices, we selected subgroups of 27 patients (subgroup A) and 47 (subgroup B) patients with VDD-CRT in 2000-2016, and 36 subjects (subgroup C) with DDD-CRT implanted were selected in 2017-2020. (3) Results: There was a trend of a lower complication rate with VDD-CRT systems, especially concerning infections during 2000-2016 (p = 0.0048), but similar results were obtained after rigorous selection of patients and employment of an upgraded design of devices/leads. With a proper device programing, CRT pacing had similar results, atrial undersensing being minimal (p = 0.65). For VDD-systems, VVI pacing was recorded only 1.7 ± 2.24% of the time. (4) Conclusions: In patients with a less favorable venous anatomy, VDD-CRT systems may represent a safe alternative regarding complications rates and functional parameters.
Keywords: VDD–CRT system; VVI pacing; atrial undersensing; cardiac resynchronization therapy (CRT); complication rate.