Behavior of the PR Interval with Increasing Heart Rate in Patients with COVID-19

Pavri, Behzad B.; Kloo, Juergen; Farzad, Darius; Riley, Joshua M.

BACKGROUND: Myriad manifestations of cardiovascular involvement are described in Coronavirus disease 2019 (COVID-19) but there have been no reports of COVID-19 affecting the cardiac conduction system. The PR interval on the electrocardiogram (ECG) normally shortens with increasing heart rate (HR). We encountered a COVID-19 patient manifesting Mobitz 1 atrioventricular (AV) block which normalized as he improved, prompting us to investigate PR interval behavior in COVID-19. OBJECTIVES: To characterize PR interval behavior in hospitalized COVID-19 patients, and correlate with clinical outcomes. METHODS: This study was a cross-sectional cohort analysis of confirmed COVID-19 cases (March 26–April 25, 2020). We reviewed pre-COVID-19 and COVID-19 ECGs to characterize AV conduction by calculating the PR interval to HR (PR:HR) slope. Clinical endpoints were death or need for endotracheal intubation. RESULTS: ECGs from 75 patients (246 pre-COVID-19 ECGs and 246 COVID-19 ECGs) were analyzed for PR:HR slope. Of these, 38 patients (50.7%) showed the expected PR interval shortening with increasing HR (negative PR:HR slopes), whereas 37 patients (49.3%) showed either no change (8 with PR:HR slopes=0) or paradoxical PR interval prolongation (29 with positive PR:HR slopes) with increasing HR. Patients without PR interval shortening were more likely to die (11/37, 29.7% vs. 3/38, 7.9%, P=0.019) or require endotracheal intubation (16/37, 43.2% vs. 8/38, 21.1%, P=0.05) compared to patients with PR interval shortening. CONCLUSION: Half of COVID-19 patients showed abnormal PR interval behavior (paradoxical prolongation or lack of shortening) with increasing HR. This finding was associated with increased risk of death and need for endotracheal intubation.