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Ventricular fibrillation: one spiral or many?
S J Evans1, H M Hastings, S Nangia
1Harris Chasanoff Heart Institute, Long Island Jewish Medical Center, New Hyde Park, NY 11042, USA.
Insights
Sudden cardiac death from ventricular fibrillation is common, but its cause is unclear. This study shows fibrillation onset involves multiple stages, with spiral wave breakdown being a key step, not a single wave.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Computational Biology
Background:
- Ventricular fibrillation (VF) is a primary cause of sudden cardiac death.
- The precise mechanisms initiating VF remain incompletely understood.
- Understanding VF onset is critical for developing effective treatments.
Purpose of the Study:
- To investigate the spatial and temporal dynamics of VF initiation.
- To differentiate between single spiral wave dynamics and the onset of fibrillation.
- To elucidate the role of spiral wave breakdown in the transition to VF.
Main Methods:
- Utilized a stable canine model to study ventricular fibrillation.
- Analyzed spatial and temporal variability of mean interactivation intervals.
- Compared experimental data with theoretical models of spiral wave dynamics.
Main Results:
- Temporal variability of activation intervals was minimal, indicating stable physiological conditions.
- Spatial variability was significantly higher, inconsistent with a single meandering spiral wave.
- Findings support that a single spiral wave cannot induce ventricular fibrillation.
Conclusions:
- The onset of ventricular fibrillation is a complex, multistage process.
- Spiral wave breakdown is identified as a crucial step in the quasi-periodic route to fibrillation.
- This research refines our understanding of the pathophysiology of sudden cardiac death.
Abstract:
Ventricular fibrillation is the major cause of sudden cardiac death, the leading cause of death in the industrialized world; however, the mechanisms for its onset are not well understood. To further understand the dynamics of fibrillation at and near its onset, we compared spatial and temporal variability of mean interactivation intervals in a stable canine model for ventricular fibrillation. Temporal variability was very small, suggesting that the relevant physiological parameters remained constant during our experiments. Spatial variability was usually significantly larger and appeared incompatible with the dynamics of a single, meandering spiral wave. This confirmed recent results that a single spiral wave cannot generate ventricular fibrillation. Thus the onset of fibrillation is a multistage process, with spiral-wave breakdown providing a crucial step in the quasi-periodic route to fibrillation.