VIEW AN ABSTRACT

Background: It is not completely understood whether cardiac rhythm conversions during cardiopulmonary resuscitation (CPR) in refractory out-of-hospital cardiac arrest (OHCA) affect outcome. A Prague OHCA study demonstrated that an invasive approach is a feasible and effective treatment strategy in refractory OHCA.
In this post-hoc analysis, we aimed to stratify the outcome according to the detailed course of heart rhythm during pre-hospital and early hospital periods and compared in patients treated with extracorporeal vs. conventional CPR.
Methods: All patients randomized to the Prague OHCA study were enrolled in this analysis. First documented, during the resuscitation and on admission, heart rhythms were analyzed in relation to neurological outcome after 180 days (the primary outcome).
Results: Within the study cohort of 256 patients (median 58 years, 17 % females), 156 (61 %) manifested ventricle fibrillation, 45 (18 %) asystole, and 55 (21 %) pulseless electrical activity as an initial rhythm. Patients with an initial VF who reached a sustained recovery of spontaneous circulation (ROSC) had the highest proportion of achieving a primary outcome: 32/44 (73 %). No patient with an initial VF who converted to asystole as their on-admission rhythm (24 cases) attained a neurologically favorable outcome at 180 days; HR 3.44 (95% CI 1.76-6.74). Patients who experienced intermittent ROSC showed a higher success rate in achieving the primary outcome when treated with a invasive approach compared to the conventional strategy: 26 out of 34 (76%) versus 24 out of 50 (48%); p < 0.05.
Conclusion: Rhythm conversions during CPR in refractory OHCA are associated with outcome, with Intermittent or sustained ROSC being the most favorable predictors. Patients presenting with VF with intermittent ROSC who remain in VF are optimal candidates for an invasive approach.