Taylor TG, Esibov A, Melnick SB, et al. - Researchers conducted a randomized trial in an experimental model of prolonged cardiac arrest in order to compare time-varying CPR (TVCPR), alternating between 100 and 200 compressions per minute (cpm) every 6 seconds, with guidelines CPR (Control). In 20 anesthetized pigs (28.4–45.8 kg), they electrically induced ventricular fibrillation (VF). CPR was initiated following 10 minutes of untreated VF, randomized to TVCPR or Control. Outcomes revealed significant improvement in indicators of net forward blood flow and proportion of return of spontaneous circulation over time in correlation with time-varying CPR with no negative impact on perfusion pressures. Alternating CC rate alternates between perfusion pressures favoring the brain and those favoring the heart. For optimizing CPR, time-varying CPR is suggested to be a new avenue of research.