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Assessment of the optimal atrio-ventricular delay in DDD paced patients by impedance plethysmography
M Eugene1, G Lascault, R Frank
1Explorations Fonctionnelles, Hôpital Pitié Salpétrière, Paris, France.
Insights
Determining the optimal atrioventricular (AV) delay for dual-chamber pacemakers is challenging. Modified impedance plethysmography accurately identifies optimal AV delay settings, improving cardiac output in DDD pacing.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Sequential atrioventricular (AV) pacing offers hemodynamic benefits dependent on AV delay and pacing rate.
- Optimal AV delay determination is clinically challenging for individual patients.
Purpose of the Study:
- To assess stroke volume variations using a modified impedance plethysmography method.
- To determine optimal AV delay and pacing rate settings in patients with dual-chamber pacemakers.
Main Methods:
- Modified impedance plethysmography was employed to measure stroke volume variations.
- Impedance measurements were correlated with CO2 rebreathing methods in VVI patients.
- Optimal AV delay was set in DDD patients across various pacing rates.
Main Results:
- Impedance plethysmography showed good correlation with established stroke volume measurement techniques.
- An inverse relationship between optimal AV delay and pacing rate was observed but not predictable.
- Cardiac output was consistently higher in DDD mode with optimal AV delay compared to VVI mode.
Conclusions:
- Modified impedance plethysmography provides accurate, non-invasive, and rapid measurements for optimizing AV delay.
- This method is suitable for routine patient examinations with dual-chamber pacemakers.
- Optimized AV delay in DDD pacing enhances cardiac output compared to VVI pacing.
Abstract:
The beneficial haemodynamic effects of sequential atrioventricular (AV) pacing have been clearly established and are dependent on the AV delay and pacing rate. However, the optimal AV delay is difficult to determine in each particular patient. We used a modified impedance plethysmographic method to assess variations in stroke volume for different AV delay and pacing rate settings. Impedance measurements showed a good correlation with CO2 rebreathing stroke volume measurements in VVI patients. Impedance variations were then used to set the optimal AV delay at different pacing rates in DDD patients. The inverse relationship between the optimal AV delay and the pacing rate has been accurately identified in most of the patients but is not predictable. In all cases, the cardiac output was higher in DDD mode at the optimal AV delay than in VVI mode. In some patients with a damaged myocardium, the stroke volume appeared to be highly sensitive to multiple AV delay settings. Impedance plethysmography can permit such repetitive non-invasive quick measurements, increasing the accuracy of optimal AV delay determination and is well suited for routine examination of patients with cardiac dual chamber pacemakers.
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