Impact of Cardiac Rhythm Dynamics during Cardiopulmonary Resuscitation on Clinical Outcomes in Patients Treated with Extracorporeal Cardiopulmonary Resuscitation (ECPR): A Systematic Review and Meta-analysis.

BACKGROUND

Although the initial presenting cardiac rhythm is an established prognostic factor for extracorporeal cardiopulmonary resuscitation, heart rhythm dynamics during conventional cardiopulmonary resuscitation remain poorly studied. We evaluated how the evolution of rhythm affects neurological outcomes and survival among recipients of extracorporeal cardiopulmonary resuscitation.

METHODS

We systematically searched PubMed and Embase for studies evaluating rhythm dynamics, focusing on Rhythm Improvement (from non-shockable to shockable) or Rhythm Decay (from shockable to non-shockable). The primary outcome was survival with a favorable neurological outcome at the longest follow-up; the secondary outcome was overall survival. A random-effects model analysis with the Hartung-Knapp adjustment was used.

RESULTS

Ten observational studies evaluating 5183 subjects with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation were included. Rhythm improvement was associated with a higher probability of a favorable neurological outcome (RR 3.12, 95% CI 1.26-7.74; GRADE: Low) compared with refractory non-shockable rhythms. Conversely, rhythm decay reduced the likelihood of a favorable neurological outcome compared with a sustained shockable rhythm (RR 0.41, 95% CI 0.21-0.80; GRADE: Moderate). Notably, decay toward asystole showed a robust negative association with good neurological recovery (RR 0.20, 95% CI 0.09-0.45; GRADE: Moderate), whereas decay toward pulseless electrical activity did not reach statistical significance (RR 0.62, 95% CI 0.31-1.25; GRADE: Low).

CONCLUSIONS

Rhythm dynamics provide valuable prognostic insights for candidates for extracorporeal cardiopulmonary resuscitation. Rhythm decay toward asystole may predict resuscitation failure and poor neurological survival, suggesting that it should prompt a critical re-evaluation of the appropriateness of extracorporeal cardiopulmonary resuscitation.