Cardiac biometric variables and arrhythmic events during COVID-19 pandemic lockdown in patients with an implantable cardiac monitor for syncope work-up.

Aim: To assess the changes induced by the COVID-19 lockdown on cardiac biometric variables recorded using an implantable cardiac monitor (ICM) in a patient population monitored for syncope work-up, as well to assess whether there has been an effect on arrhythmic events among the patients. Methods: Longitudinal cohort study. We included 245 adult patients monitored with an ICM indicated for the investigation of syncope. The records from days 1 to 12 March 2020 (prior to the institution of lockdown by the state government) with days 16 to 28 March 2020 were compared. Results: Daily physical exercise reduced markedly after the imposition of lockdown (132 [55-233] minutes vs. 78 [21-154] minutes). The mean daytime HR prior to lockdown was 77 [69-85] bpm, whereas during lockdown it was 74 [66-81] bpm. During the lockdown period, a drop in the variability in heart rate (114 [94-136] ms vs. 111 [92-133] ms) was observed. Although the incidence of AF was similar over both periods, the daily AF burden was significantly higher post-lockdown (405 [391-425] minutes vs. 423 [423-537] minutes). No differences in the number of other arrhythmias were found. Conclusions: The establishment of mandatory lockdown has led to a marked drop in daily physical activity in this population which probably explains changes observed in other cardiac biometric variables. Although, in the short term, we have not documented an increased risk of arrhythmia, we cannot rule out an effect in the medium to long term or in other populations of at-risk patients.