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Efficacy and safety of ventricular rate responsive pacing in children with complete atrioventricular block
P Ragonese1, P Guccione, F Drago
1Department of Pediatric Cardiology, Ospedale Bambino Gesù, Research Institute Rome, Italy.
Insights
Single chamber rate responsive pacing (VVIR) is effective for children with heart block, adequately meeting physiological needs during daily activities and exercise. Atrioventricular synchrony preservation may not be necessary for all pediatric patients.
Area of Science:
- Pediatric Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Single chamber rate responsive pacing (VVIR) presents potential advantages over dual chamber pacing in pediatric patients.
- Preservation of atrioventricular synchrony may not be essential for all pediatric patients requiring pacing.
- Chronic third-degree atrioventricular block necessitates permanent pacing solutions in children.
Purpose of the Study:
- To evaluate the efficacy and safety of ventricular rate responsive (VVIR) pacemakers in pediatric patients.
- To assess the physiological response to VVIR pacing during daily activities and exercise.
- To determine if VVIR pacing adequately meets the needs of children with chronic heart block.
Main Methods:
- Implantation of VVIR pacemakers in 22 pediatric patients (9 months to 12 years) with chronic third-degree atrioventricular block.
- 24-hour Holter monitoring and graded treadmill tests (VVI vs. VVIR modes) for follow-up.
- Analysis of paced ventricular rates, correlation with spontaneous atrial rhythm, and exercise tolerance.
Main Results:
- VVIR pacemakers maintained normal paced ventricular rates for age in all patients.
- Six patients required pacemaker reprogramming due to significant rate variations.
- A significant correlation was observed between paced rate and spontaneous atrial rhythm variations (P < 0.05).
- Exercise tolerance was normal in VVIR mode, with improved maximal heart rates and blood pressure compared to VVI mode (P < 0.0013).
Conclusions:
- Ventricular rate responsive pacing adequately responds to the physiological demands of selected pediatric patients.
- VVIR pacing is a viable and effective pacing mode for children with chronic third-degree atrioventricular block.
- This pacing strategy may offer a simpler alternative to dual chamber pacing in specific pediatric populations.
Abstract:
Single chamber rate responsive pacing offers many potential advantages over the more complex dual chamber atrial tracking pacing mode in children, and the preservation of atrioventricular synchrony could be unnecessary in selected groups of pediatric patients. Twenty-two pediatric patients (age range 9 months to 12 years; mean 6.5 years) had implantation of ventricular rate responsive (VVIR) pacemakers over a 2-year period. All patients had chronic third-degree atrioventricular block, and a normal ventricular function at rest. During the follow-up each patient underwent a 24-hour Holter monitoring, and ten performed a graded treadmill test in both ventricular fixed rate (VVI) and rate responsive (VVIR) pacing mode. Paced ventricular rates were found to be normal for age in all 22 patients; maximum rate did not reach the higher programmed rate during daily activities in any patient. Comparing the mean paced ventricular rate to the mean rates of blocked P waves, six patients showed a difference of more than 20 beats/min, which induced the pacemaker parameters to be reprogrammed. In all patients a significant correlation was found between variations of paced ventricular rate and variations of spontaneous blocked atrial rhythm (P < 0.05); this correlation persisted in the subsequent Holter controls in the ten patients with longer follow-up. Exercise tolerance resulted normal in the ten patients who performed a treadmill test either in VVIR or VVI mode, with increased maximal heart rates and maximal systolic blood pressure in VVIR mode (P < 0.0013). Rate responsive ventricular pacemakers seem to adequately respond to the physiological needs of daily life of this selected group of children requiring permanent pacing.