Key result
Sensolog III pacemakers produce excessive acceleration during stair descent compared to Dash devices.
Why the study?
Does an accelerometer-controlled pacemaker improve heart rate response during daily activities compared to a vibration piezoelectric-controlled pacemaker in patients with chronic atrial fibrillation?
RCT (n=23)
Randomly assigned
Does an accelerometer-controlled pacemaker improve heart rate response during daily activities compared to a vibration piezoelectric-controlled pacemaker in patients with chronic atrial fibrillation?
Absolute Event Rate: 2.9% vs 1.8%
p-value: p=0.04
Accelerometer-driven pacemakers provide a heart rate response closer to that of healthy controls during daily activities compared to vibration piezoelectric-controlled pacemakers.
Vibration piezoelectric sensors risk excessive rate acceleration on descent; challenges sensor equivalence and favors accelerometers in VVIR pacing for AF.
To optimize programming of rate adaptive pacemakers (RAPs), we explored a new mathematical method to assess the performance of RAPs during daily-life tests, using customized Windows-based software. By stepwise discriminant analysis and linear regression, this method allows calculation of the acceleration and deceleration capacity of pacemakers and their general behavior during effort and recovery phases. Twenty-three patients (10 females and 13 males; 68 +/- 8 years) with chronic atrial fibrillation and a slow ventricular response were evaluated. They randomly received an accelerometer-controlled VVIR Dash Intermedics pacemaker (10 patients) or a vibration piezoelectric-controlled VVIR Sensolog III Siemens pacemaker (13 patients). All patients underwent the same test protocol: 6 minutes walking, 1.5 minutes climbing stairs, 1.5 minutes descending stairs, and 0.5 minutes sit-ups. By definition, the pacemaker responsiveness slope was programmed so that the heart rate response of paced patients during the walking test corresponded best to that of healthy controls. The slope was left unchanged for the other tests. We considered four scores: an acceleration score (EA score), an effort rate score (ER score), a deceleration score (RD score), and a recovery rate score (RR score). Scores ranged from -10 (hypochronotropic behavior of the pacemaker) to +10 (hyperchronotropic behavior), based on daily-life tests of 15 healthy controls (7 females and 8 males, 65 +/- 9 years). A score of 0 represented exact concordance with healthy controls. During stair descent, the Sensolog III produced excessive acceleration (EA score = +2.9 +/- 1.1) compared to: (1) stair climbing (EA score = -4.0 +/- 1.9; P = 0.01, with the same pacemakers); and (2) the Dash (+1.8 +/- 1.9; P = 0.04) and healthy controls (P = 0.02). The sit-up tests revealed a hypochronotropic response of both pacemakers compared to healthy controls, with a larger difference for the Sensolog III (EA score = -2.0 +/- 5.8; P = 0.04; RD score = -6.8 +/- 3.8' P = 0.02). We conclude that activity-driven pacemakers can accommodate brief activities, except for isovolumetric exercise such as sit-ups. During daily activities, accelerometer-driven pacemakers seem to provide a heart rate resoibse closer to that of healthy controls. Our new mathematical analysis is a simple and reproducible method for evaluating and quantifying the efficacy of any sensor-driven pacemaker.
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Garrigue et al. (1998) conducted an RCT in Chronic atrial fibrillation and a slow ventricular response (n=23). Vibration piezoelectric-controlled VVIR Sensolog III Siemens pacemaker vs. Accelerometer-controlled VVIR Dash Intermedics pacemaker was evaluated on Acceleration score (EA score) during stair descent (p=0.04). During stair descent, the Sensolog III pacemaker produced excessive acceleration compared to the Dash pacemaker (EA score +2.9 vs +1.8; P=0.04) and healthy controls.