Ventricular fibrillation dynamics reveal regional asymmetry in resilience to cardiac arrest and predict clinical outcome.

Summary

In porcine models, VF exhibited consistent right-to-left ventricular activation rate gradients that intensified with prolonged global ischaemia, driven by greater RV resilience. Computational simulations corroborated higher RV excitability under ischaemia. In 60 patients with out-of-hospital cardiac arrest, higher pre-shock VF activation rates were associated with favourable neurological outcomes.

Key Findings

• Right ventricle shows higher activation rates than left ventricle during VF, with gradients increasing over long-duration VF under global ischaemia.
• Ex vivo optical mapping and computational simulations confirm earlier LV electrical depression and sustained RV excitability.
• In 60 cardiac arrest patients, higher pre-shock VF activation rates predicted favourable neurological outcomes.

Clinical Implications

ECG-derived VF activation rate prior to first defibrillation may aid prognostication and guide resuscitation strategies. Recognition of RV-LV asymmetry could inform defibrillation timing and adjunctive therapies during prolonged VF.

Limitations

• Translational human validation was observational and limited in sample size.
• Animal models may not capture all human comorbidities and arrest heterogeneity.

Future Directions

Prospective validation of ECG-derived activation rate as a prognostic tool in resuscitation trials and exploration of tailored defibrillation strategies leveraging RV-LV asymmetry.