The QT Scale: A Weight Scale Measuring the QTc Interval

• Published in: Annals of noninvasive electrocardiology 2017-01, Vol.22 (1), p.np-n/a
• Main Authors: Couderc, Jean‐Philippe, Beshaw, Connor, Niu, Xiaodan, Serrano‐Finetti, Ernesto, Casas, Oscar, Pallas‐Areny, Ramon, Rosero, Spencer, Zareba, Wojciech
• Format: Article
• Language: English
• Subjects: Adult; Anti-Arrhythmia Agents - therapeutic use; Atrial Fibrillation - drug therapy; Atrial Fibrillation - physiopathology; clinical; Electrocardiografia; Electrocardiography; electrophysiology; Enginyeria de la telecomunicació; Female; Heart Conduction System - physiopathology; Heart Rate - physiology; Humans; long QT syndrome; Long QT Syndrome - physiopathology; Male; Middle Aged; noninvasive techniques; Original; Phenethylamines - therapeutic use; Sulfonamides - therapeutic use; Àrees temàtiques de la UPC
• ISSN: 1082-720X; 1542-474X; 1542-474X
• DOI: 10.1111/anec.12378

Introduction Despite the strong evidence of the clinical utility of QTc prolongation as a surrogate marker of cardiac risk, QTc measurement is not part of clinical routine either in hospital or in physician offices. We evaluated a novel device (“the QT scale”) to measure heart rate (HR) and QTc interval. Method The QT scale is a weight scale embedding an ECG acquisition system with four limb sensors (feet and hands: lead I, II, and III). We evaluated the reliability of QT scale in healthy subjects (cohort 1) and cardiac patients (cohorts 2 and 3) considering a learning (cohort 2) and two validation cohorts. The QT scale and the standard 12‐lead recorder were compared using intraclass correlation coefficient (ICC) in cohorts 2 and 3. Absolute value of heart rate and QTc intervals between manual and automatic measurements using ECGs from the QT scale and a clinical device were compared in cohort 1. Results We enrolled 16 subjects in cohort 1 (8 w, 8 m; 32 ± 8 vs 34 ± 10 years, P = 0.7), 51 patients in cohort 2 (13 w, 38 m; 61 ± 16 vs 58 ± 18 years, P = 0.6), and 13 AF patients in cohort 3 (4 w, 9 m; 63 ± 10 vs 64 ± 10 years, P = 0.9). Similar automatic heart rate and QTc were delivered by the scale and the clinical device in cohort 1: paired difference in RR and QTc were −7 ± 34 milliseconds (P = 0.37) and 3.4 ± 28.6 milliseconds (P = 0.64), respectively. The measurement of stability was slightly lower in ECG from the QT scale than from the clinical device (ICC: 91% vs 80%) in cohort 3. Conclusion The “QT scale device” delivers valid heart rate and QTc interval measurements.