Derived telemetry-based electrocardiograms in the intensive care unit: insights from a COVID-19 epicenter

Introduction: Severely ill inpatients with SARS-CoV-2 infection, Coronavirus Disease 2019 (COVID-19) require close electrocardiographic (ECG) monitoring due to frequent cardiac involvement of the disease and cardiovascular side effects of therapies. This study aimed to compare ECG parameters measured from conventional 12-lead ECGs to those from a telemetry-generated 7-lead or single lead ECG to determine if the latter may be an alternative for screening and monitoring patients, particularly during a pandemic. Methods and Results: We identified 33 patients with respiratory failure due to COVID-19 undergoing telemetry monitoring in the intensive care unit. Each received a 12-lead ECG utilizing standard lead placement. A concurrent 7-lead ECG and single lead (lead II) tracing were obtained using the central telemetry system. Each ECG was interpreted and intervals manually measured by 2 cardiologists with disagreements adjudicated by a third. Compared to the 12-lead ECG measurement, the 7-lead ECG underestimated the corrected QT by on average 13.45±32.05 msec, and the single lead ECG underestimated corrected QT by 19.62±33.19 msec (Bazett, p < 0.05). Bland Altman analysis also demonstrated evidence of a positive bias, suggesting that the telemetry-derived tracings underestimated the QT interval. The presence of T wave abnormalities and ST segment changes were overestimated by the telemetry-derived tracings as compared to standard ECGs. Conclusion: Though telemetry-derived ECGs may be useful in screening patients for significant ECG abnormalities, they likely do not represent a reliable replacement of the standard 12-lead ECG in the routine diagnosis and management of critically ill patients.