Impact of ventricular ectopic burden in a premature ventricular contraction–induced cardiomyopathy animal model

Abstract

Background Frequent premature ventricular contractions (PVC) have been associated with PVC-induced cardiomyopathy (CM) in some patients. Objective Understand the cardiac consequences of different PVC burden and minimum burden required to induce LV dysfunction. Methods RV apical PVCs at a coupling interval of 240ms were introduced at different PVC burden in 9 mongrel canines. A stepwise increase in PVC burden was implemented every 8 weeks from 0% (baseline), 7%, 14%, 25%, 33% to 50% using our premature pacing algorithm. Echocardiogram and 24-hr Holter were obtained at 4- and 8-week period at each PVC burden with a single blinded reader assessing all echocardiographic parameters including speckle tracking imaging (GE EchoPAC). CM was defined as LVEF < 50% or a decrease >10% points. IL-6 and pro-BNP levels were obtained at the end of each PVC burden. Results LVEF±SD (mean heart rate ± SD) for 0%, 7%, 14%, 33%, and 50% at 8 weeks for each PVC burden were 57±2.9% (85±13bpm); 54.4±3% (81±10bpm); 53.3±5% (77±12bpm); 51.1±4.2% (79±14bpm); 47.7±3.8% (80±14bpm); 44.7±1.9% (157±43bpm). PVC-induced CM was present in 11.1%, 44.4%, and 100% of animals with 25%, 33% and 50% PVC burden, respectively. E/A ratio and radial strain decreased while LA size increased beyond 33% PVC burden. No changes in pro-BNP and IL-6 levels were noted at any PVC burden. Conclusion LV systolic function (LVEF, and radial strain) declined linearly as PVC burden increased. PVC-induced CM developed in some canines with 25% and 33% PVC burden, but developed in all animals with 50% PVC burden.

Assessment of subtle cardiac dysfunction in patients with frequent premature ventricular complexes by real‐time three‐dimensional speckle tracking echocardiography

“…Several previous studies concluded that premature beat load was negatively correlated with cardiac function, suggesting that premature beat load was 1 of the risk factors for development of PVC‐induced cardiomyopathy . The present study compared patients with different PVC loads using 20% as a cutoff, and found that those with higher PVC loads had numerically but not significantly larger EDV and ESV values but lower LVEF and strain values.…”

Premature Ventricular Contraction Coupling Interval Variability Destabilizes Cardiac Neuronal and Electrophysiological Control

“…Additionally, whether the differential effect of the CI seen on cardiac electrical stability and neuronal behavior is dependent on a specific burden 43 or a PVC location remain unknown. Indeed, we studied PVCs from only one location (RVOT), which is the most commonly encountered clinically, and investigating different locations in this set of animals was not feasible.…”

Quantification of Left Ventricular Function With Premature Ventricular Complexes Reveals Variable Hemodynamics

“…In addition, this technique may allow for improved patient selection for PVC ablations as eliminating low stroke volume PVCs might be more beneficial. Lastly, some patients with frequent PVCs and preserved EF may have a subclinical cardiomyopathy as demonstrated by abnormal radial strain 21 , which has been recently corroborated in animal models 22 . Our approach may provide another means to identify subclinical cardiomyopathy, which might lead to earlier initiation of care and avoid the development of an overt cardiomyopathy.…”