Correlation between mobile and 12-lead ECG among patients loading with intravenous sotalol: A PEAKS substudy

Background: Electrocardiographic monitoring is performed during sotalol loading, primarily to assess QTc. Continuous telemetry increases resource utilization, generating interest in streamlining QTc monitoring through mobile technologies. Objective: Assess feasibility and outcomes of mobile electrocardiogram (ECG) monitoring during intravenous sotalol loading. Methods: In a substudy of the PEAKS (Prospective Evaluation Analysis and Kinetics of IV Sotalol) registry, AliveCor 6L mobile ECGs were recorded during intravenous sotalol loading, concomitantly with standard 12-lead ECGs. We calculated the correlation of heart rate and QTc between them. Results: Overall, 77 patients were included: the median age was 68 years (interquartile range 63-73 years) and 20% were female. A total of 227 mobile recordings were performed within 30 minutes of 12-lead ECG, including baseline (8%), during infusion (54%), during oral dosing (35%), and during follow-up (0.4%). Half (51%) of 12-lead tracings were in atrial tachycardia (AT)/atrial fibrillation (AF), with a 93% correlation with automated mobile diagnostics. No mobile QTc values were available for recordings in AT/AF. The overall correlation between 12-lead ECG and mobile ECG was good for continuous heart rate (R > 0.8) but was poor for continuous QTc (R = 0.24). Most physiologic QTc values from the mobile ECGs were within 10% of the adjudicated 12-lead values (83%), with 53% within 5%. There were few false negative values for QTc >500 ms by mobile ECG (n = 2 of 58 [3.4%]). Conclusion: Mobile ECGs can be performed during sotalol loading but are limited by the absence of QTc in AT/AF. While QTc values from automated mobile 6-lead ECGs appeared to detect cases of QTc prolongation in sinus rhythm, additional data are needed prior to use for routine clinical monitoring. ClinicalTrialsgov ID: NCT05247320.