Benzodiazepine-Free Cardiac Anesthesia for Reduction of Delirium (B-Free): A Two-Centre Pilot Study to Determine the Feasibility of a Multi-Centre, Randomized, Cluster Crossover Trial

Abstract

BACKGROUND: Latent causes of apparently unexplained cardiac arrest (UCA) may influence the risk of life-threatening recurrence. We reported the arrhythmic outcomes in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER). METHODS: CASPER is a prospective Canadian registry of cardiac arrest survivors and their first-degree relatives (FDR). Patients were enrolled at 14 centers with demographics, cardiac diagnoses, and follow-up events recorded. Patients with significant coronary artery disease were excluded, and all patients had at least one follow-up visit. Kaplan-Meier and Cox regression analyses were used to compare a composite event of cardiac arrest, appropriate ICD shock, or ATP. RESULTS: 670 patients (330 probands, 340 FDR) were enrolled with a median age of 43 years (IQR 29-53 years, 53% male). Diagnostic categories included structural (9% probands vs. 6% FDRs), electrical (20% vs. 26%), idiopathic (71% of probands), and unaffected (68% of FDRs). Specific diagnoses included structural disease (8%; 4% ARVC, 0.5-1% for each HCM, DCM, coronary spasm, myocarditis), electrical (23%; 12% LQTS, 4% CPVT, 4% Brugada), idiopathic (35%, probands only), and unaffected (33%, FDRs only). 54 patients (8%) had a pathogenic mutation and 348 patients (95% of probands, 10% of FDRs) had an ICD at follow-up. The median follow-up was 3.5 years (IQR 1.56-4.97, cumulative 2517.8 patient-years) with a similar follow-up between probands (3.2 years, IQR 1.82-5.07) and FDRs (2.7 years, IQR 1.30-4.88). 18% of probands experienced an event, compared to 1% of FDRs (p<0.001), with a median time-to-event of 1.08 years (IQR 0.41-2.65). Follow-up events included ICD shock (11%, appropriate and inappropriate), ATP (6%), appropriate shock or ATP (10%), and syncope (7%), with 1% of patients deceased at follow-up. Patients with structural diagnoses had a higher composite event rate compared to electrical (Figure, KM analysis, p¼0.009), and electrical/ idiopathic combined (p¼0.009), with unaffected patients having no events (p<0.001). Among probands, structural diagnoses were an independent predictor of recurrent events (OR 3.45, Table). Among relatives,