Key Points
- To evaluate how electrical potentials from distant left ventricular depolarization affect the morphology and timing of local right ventricular unipolar epicardial electrograms.
- Performed a surgical right ventricular isolation procedure in an experimental model to prevent electrical conduction wavefronts from propagating between ventricles.
- Paced the ventricles asynchronously (left ventricle paced 100 ms prior to right ventricle) to isolate local from distant components, and synchronously (<= 20 ms interval) to simulate normal activation.
- Distant left ventricular depolarization significantly altered the magnitude of the maximum slope and the timing of maximum/minimum potentials in right ventricular electrograms, but did not significantly alter the timing of the fastest 1 ms downstroke.
- No distant electrogram components showed negative slopes with magnitudes > 1.3 mV/ms, whereas no local-only electrogram components had negative slope magnitudes < 1.5 mV/ms.
- Simulated electrograms reconstructed from isolated local and distant components correlated strongly with electrograms recorded during synchronous pacing (r = 0.83 to 1.00, N = 48).
Structured PICO
Does distant cardiac electrical activity affect local activation in unipolar epicardial electrograms?
PPopulationExperimental model undergoing right ventricular isolation procedure
IInterventionAsynchronous pacing (left ventricle paced 100 ms before right ventricle)
CComparatorSynchronous pacing (interval of 20 ms or less between pacing the ventricles)
OOutcomeMagnitude of the slope of the most rapid deflection and timing of maximum and minimum potentials of right ventricular unipolar electrogramssurrogate
Distant cardiac electrical activity affects the magnitude and timing of potentials in unipolar epicardial electrograms, but the timing of the fastest downstroke remains a reliable marker of local activation.