Evolution Of The Gain In Spontaneous Conduction Between Atrio-Ventricular Delay Hysteresis Algorithms And A New Pacing Mode

Most of studies show the interest to decrease ventricular pacing in patients implanted with a dual chamber pacemaker (PM). Algorithms developed to search spontaneous ventricular activity consisted first in increasing AV delay (AV delay hysteresis: AVDH). More recently, new modes of pacing were proposed: MVPTM mode (Managed Ventricular Pacing) Medtronic-USA. The aim of this study was to evaluate the gain of spontaneous conduction between different generations of AVDH and the MVPTM mode. Methods we studied two populations of patients implanted for conduction disorder (CD) or sinus dysfunction (SD) distributed in three groups. Group I: 115 patients implanted with Kappa® series PM (Medtronic-USA) and first generation AVDH (AVDH, CD: 56%, SD: 44%). Group II: 168 patients implanted with Enpulse® series PM (Medtronic-USA) and 2nd generation AVDH (AVDH+, CD: 52%, SD: 48%). Group III: 156 patients implanted with Adapta® series PM (Medtronic-USA) and the MVPTM; mode (CD: 40%, SD: 60%). Populations were not different in sex, age and pacing indications. Patients who presented less than 1% of spontaneous ventricular activity were excluded from analysis. We compared first the gain in ventricular detection induced by AVDH vs. AVDH+ and secondly the percentage of ventricular pacing between AVDH+ and MVP in the two populations (Mood's median test). Results shown in the following table: Conclusion AVDH+ results in a decrease in VP in patients without conduction disorder but not in patients with conduction disorder. The use of MVPTM results in a significant decrease of ventricular pacing compared to first and second generation of AVDH algorithms in both patients with or without conduction disorder with a high gain in spontaneous AV conduction. AVDH AVDH (+) MVP % VP with conduction disorder Median 99.7 N.S. 99.7 p  15.0 1st, 3rd quart 97.1 – 99.8 66.1 – 100 1.4 – 79.2 % VP without conduction disorder Median 78.5 p 25.8 p 1.8 1st, 3rd quart 43 – 95.1 6.9 – 72.7 1.3 – 5.6