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Simultaneous vs. sequential biventricular pacing in dilated cardiomyopathy: an acute hemodynamic study
Giovanni B Perego1, Roberto Chianca, Mario Facchini
1Istituto Auxologico Italiano, Ospedale S. Luca, Via Spagnoletto 3, 20149 Milan, Italy. perego@auxologico.it
Insights
Sequential biventricular pacing optimizes atrioventricular and interventricular delays, significantly improving left ventricular systolic performance in heart failure patients. This method offers a hemodynamic advantage over simultaneous pacing in selected cases.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Dilated cardiomyopathy and intraventricular conduction delay impair left ventricular (LV) systolic function.
- Simultaneous biventricular pacing is established to improve LV performance.
Purpose of the Study:
- To investigate if sequential biventricular pacing, by optimizing atrioventricular and interventricular delays, can further enhance LV systolic performance compared to simultaneous pacing.
- To determine optimal interventricular delays for sequential pacing.
Main Methods:
- Acute hemodynamic measurements of LV and RV pressure and dP/dt in 12 patients.
- Comparison of sequential vs. simultaneous biventricular pacing with varying atrioventricular and interventricular (VVi) intervals (-60 to +40 ms).
Main Results:
- Sequential biventricular pacing resulted in a significantly higher average increase in maximum LV dP/dt compared to simultaneous pacing (VDD mode: 35% vs. 29%; DDD mode: 38% vs. 34%).
- Optimal interventricular delays averaged -25 ms in both VDD and DDD modes, indicating a preference for early LV stimulation.
- Right ventricular dP/dt remained unchanged, and QRS shortening did not predict LV dP/dt improvement.
Conclusions:
- Sequential biventricular pacing can significantly increase LV systolic performance without affecting RV function.
- Optimizing interventricular delay, specifically stimulating the LV before the RV, yields the greatest hemodynamic benefit.
- This approach may offer clinical significance for select heart failure patients.
Aims:
Simultaneous biventricular pacing improves left ventricular (LV) systolic performance in patients with dilated cardiomyopathy and intraventricular conduction delay. We tested the hypothesis that further improvements can be obtained using sequential biventricular pacing by optimizing both atrioventricular and interventricular delays.
Methods And Results:
In 12 patients, LV pressure, right ventricular (RV) pressure and respective rates of change of pressure (dP/dt) were acutely measured during biventricular pacing with different atrioventricular and interventricular (VVi) intervals ranging from -60 to +40 ms. The average increase vs. baseline in maximum LV dP/dt was higher for sequential than for simultaneous biventricular pacing (VDD mode: 35+/-20 vs. 29+/-18%, P<0.01; DDD mode: 38+/-23 vs. 34+/-25%, P<0.01), with a minority of patients accounting for most of the difference. The mean optimal VVi was -25+/-21 ms in VDD mode and -25+/-26 ms in DDD mode. With these settings, RV dP/dt was not significantly different from baseline. QRS shortening was not predictive of LV dP/dt increase.
Conclusion:
A significant increase of LV dP/dt with no change in RV dP/dt can be obtained by sequential biventricular pacing as compared to simultaneous biventricular pacing. The highest LV dP/dt is achieved when LV is stimulated before RV. The hemodynamic advantage might be of clinical significance in selected cases.
