Key result
Noninvasive assessment of the ventricular force-frequency relationship identified a significantly different best and worst ventricular pacing strategy for each patient (p<0.001), demonstrating wide intra- and inter-patient variability in optimal pacing.
Why the study?
Do different ventricular pacing strategies alter ventricular force-frequency relationships in pediatric and young adult patients with congenital heart disease?
Cross-Sectional (n=10)
No
Do different ventricular pacing strategies alter ventricular force-frequency relationships in pediatric and young adult patients with congenital heart disease?
Noninvasive assessment of ventricular force-frequency relationships demonstrates wide inter- and intra-patient variability in optimal biventricular pacing strategies in congenital heart disease, emphasizing the need for individualized and rate-responsive pacing modulation.
Highlights need for individualized pacing in congenital heart disease; leaves open prospective validation of noninvasive FFR assessment.
BACKGROUND: Traditional indices to evaluate biventricular (BiV) pacing are load dependent, fail to assess dynamic changes, and may not be appropriate in patients with congenital heart disease (CHD). We therefore measured the force-frequency relationship (FFR) using tissue Doppler-derived isovolumic acceleration (IVA) to assess the dynamic adaption of the myocardium and its variability with different ventricular pacing strategies. METHODS: This was a prospective pilot study of pediatric and young adult CHD patients with biventricular or multisite pacing systems. Color-coded myocardial velocities were recorded at the base of the systemic ventricular free wall. IVA was calculated at resting heart rate and with incremental pacing. FFR curves were obtained by plotting IVA against heart rate for different ventricular pacing strategies. RESULTS: Ten patients were included (mean: 22 ± 7 years). The FFR identified a best and worst ventricular pacing strategy for each patient, based on the AUC at baseline, submaximal, and peak heart rates (P < .001). However, there was no single best ventricular pacing strategy that was optimal for all patients. Additionally, the best ventricular pacing strategy often differed within the same patient at different heart rates. CONCLUSION: This novel assessment demonstrates a wide variability in optimal ventricular pacing strategy. These inherent differences may play a role in the unpredictable clinical response to BiV pacing in CHD, and emphasizes an individualized approach. Furthermore, the optimal ventricular pacing varies with heart rate within individuals, suggesting that rate-responsive ventricular pacing modulation may be required to optimize ventricular performance.
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Baskar et al. (2018) conducted a cross-sectional in Congenital heart disease with biventricular or multisite pacing (n=10). Different ventricular pacing strategies (BiV, multisite, single lead) vs. Intra-patient comparison (best vs worst pacing strategy) was evaluated on Area under the curve (AUC) of the force-frequency relationship (FFR) using isovolumic acceleration (IVA) (p=<0.001). Noninvasive assessment of the ventricular force-frequency relationship identified a significantly different best and worst ventricular pacing strategy for each patient (p<0.001), demonstrating wide intra- and inter-patient variability in optimal pacing.
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