Physical Activity, Heart Rate Variability, and Ventricular Arrhythmia During the COVID-19 Lockdown: Retrospective Cohort Study.

BACKGROUND: Ventricular arrhythmias (VAs) increase with stress and national disasters. Prior research has reported that VA did not increase during the onset of the COVID-19 lockdown in March 2020, and the mechanism for this is unknown. OBJECTIVE: This study aimed to report the presence of VA and changes in 2 factors associated with VA (physical activity and heart rate variability [HRV]) at the onset of COVID-19 lockdown measures in Ontario, Canada. METHODS: Patients with implantable cardioverter defibrillator (ICD) followed at a regional cardiac center in Ontario, Canada with data available for both HRV and physical activity between March 1 and 31, 2020, were included. HRV, physical activity, and the presence of VA were determined during the pre- (March 1-10, 2020) and immediate postlockdown (March 11-31) period. When available, these data were determined for the same period in 2019. RESULTS: In total, 68 patients had complete data for 2020, and 40 patients had complete data for 2019. Three (7.5%) patients had VA in March 2019, whereas none had VA in March 2020 (P=.048). Physical activity was reduced during the postlockdown period (mean 2.3, SD 1.6 hours vs mean 2.1, SD 1.6 hours; P=.003). HRV was unchanged during the pre- and postlockdown period (mean 91, SD 30 ms vs mean 92, SD 28 ms; P=.84). CONCLUSIONS: VA was infrequent during the COVID-19 pandemic. A reduction in physical activity with lockdown maneuvers may explain this observation.

Predictors of early mortality in critically ill patients with acute kidney injury necessitating renal replacement therapy: A cohort study.

PURPOSE: Reliable prediction of early mortality after initiation of renal replacement therapy (RRT) in critically ill patients may inform decision-making regarding this treatment. Our primary objective was to identify predictors of mortality within 2 days of starting RRT. MATERIALS AND METHODS: Patients with acute kidney injury (AKI), receiving RRT, and admitted to intensive care units of one hospital were included. Associations between baseline risk factors and mortality at 2 days and at hospital discharge were analyzed using logistic regression. Discrimination of both models was assessed. RESULTS: We included 626 patients, treated initially with intermittent RRT (n = 300, 47.9%), continuous RRT (n = 211, 33.7%), or sustained low-efficiency dialysis (n = 115, 18.4%). Two-day mortality after starting RRT was 12.9% (n = 81), and hospital mortality was 50.5% (n = 316). Independent predictors of 2-day mortality included primary diagnostic category (p = 0.004) and sepsis-related organ failure assessment (SOFA) score (odds ratio [OR] 1.36 per point, 95% confidence interval [CI] 1.24-1.50). Independent predictors of hospital mortality included SOFA (1.29, 95%CI 1.21-1.37), Charlson score (1.20, 95%CI 1.18-1.43), and interhospital transfer (OR 0.55, 0.38-0.81). C-statistics were 0.81 (2-day mortality) and 0.80 (hospital mortality). CONCLUSIONS: Higher SOFA was associated with 2-day mortality after RRT initiation and with hospital mortality. Discrimination in both models was modest.