Development of an electrocardiogram-based risk calculator for a cardiac cause of syncope.

To develop an ECG-based tool for rapid risk assessment of a cardiac cause of syncope in patients ≥40 years. In a prospective international multicentre study, 2007 patients ≥40 years presenting with syncope were recruited in the emergency department (ED) of participating centres ranging from large university hospitals to smaller rural hospitals in eight countries from May 2010 to July 2017. 12-Lead ECG recordings were obtained at ED presentation following the syncopal event. The primary diagnostic outcome, a cardiac cause of syncope, was centrally adjudicated by two independent cardiologists using all available clinical information including 12-month follow-up. ECG predictors for a cardiac cause of syncope were identified using penalised backward selection and a continuous-scale likelihood was calculated based on regression analysis coefficients. Findings were validated in an independent US multicentre cohort including 2269 patients. In the derivation cohort, a cardiac cause of syncope was adjudicated in 267 patients (16%). Seven ECG criteria were identified as predictors for this outcome: heart rate and QTc-interval (continuous predictors), rhythm, atrioventricular block, ST-segment depression, bundle branch block and ventricular extrasystole/non-sustained ventricular tachycardia (categorical predictors). Diagnostic accuracy of these combined predictors for a cardiac cause of syncope was high (area under the curve 0.80, 95% CI 0.77 to 0.83). Overall, 138 patients (8%) were rapidly triaged towards rule-out and 181 patients (11%) towards rule-in of a cardiac cause of syncope. External validation showed similar performance. In patients ≥40 years with a syncopal event, a combination of seven ECG criteria enabled rapid assessment of the likelihood that syncope was due to a cardiac cause. NCT01548352 (BASEL IX), NCT01802398 (SRS study).

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Déclaration de conflit d'intérêts

Competing interests: The authors designed the study, gathered and analysed the data, vouch for the data and analysis, wrote the paper and decided to publish. TZ, JD and CM had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors have read and approved the manuscript. The sponsors had no role in designing or conducting the study and no role in gathering or analysing the data or writing the manuscript. The manuscript and its contents have not been published previously and are not being considered for publications elsewhere in whole or in part in any language, including publicly accessible websites or e-print servers. TZ has received research support from the Freiwillige Akademische Gesellschaft Basel (Switzerland). JEW reports a research grant from the Swiss Heart Foundation, the Swiss Academy of Medical Sciences and the Bangerter Foundation (YTCR 23/17). PB has received research funding from the University of Basel, the "Stiftung für Herzschrittmacher und Elektrophysiologie" and the Freiwillige Akademische Gesellschaft Basel. LC reports grants and personal fees from Abbott Diagnostics, grants and personal fees from Beckman Coulter, grants and personal fees from Siemens, outside the submitted work. MT reports grants and personal fees from Abbott, grants and personal fees from Alere, grants from Beckman, grants and personal fees from Roche, outside the submitted work. FJM-S received speaker, advisory or consulting fees from Novartis, MSD, Bristol-Myers Squibb, Pfizer, The Medicine Company, Otsuka, Thermo Fisher, Cardiorentis, Sanofi, and research grants from the Spanish Ministry of Health and FEDER, Mapfre, Novartis, Bayer, MSD, Abbot and Orion-Pharma, outside the submitted work. WFP reports research grants from Abbott, Braincheck, Immunarray, Janssen, Roche and ZS Pharma, having served as a consultant for Abbott, AstraZeneca, Bayer, Beckman, Boehrhinger-Ingelheim, Ischemia Care, Dx, Immunarray, Instrument Labs, Janssen, Ortho Clinical Diagnostics, Relypsa, Roche and Siemens, having provided expert testimony for Johnson and Johnson, and having ownership interests in Comprehensive Research Associates, and Emergencies in Medicine, Ischemia DX. MK reports personal fees from Bayer, personal fees from Daiichi-Sankyo, personal fees from Pfizer-BMS, personal fees from Böhringer-Ingelheim, outside the submitted work. TR has received research grants from the Goldschmidt-Jacobson Foundation, the Swiss National Science Foundation (PASMP3-136995), the Swiss Heart Foundation, the Professor Max Cloëtta Foundation, the University of Basel and the University Hospital Basel as well as speaker honoraria from Abbott, Bayer, Biosense, Brahms, Medtronic, Pfizer-BMS and Roche. BS has received consulting honoraria from Medtronic, outside the submitted work. CM has received research support from the Swiss National Science Foundation, the Swiss Heart Foundation, the European Union, the KTI, the Cardiovascular Research Foundation Basel, the University Basel, the University Hospital Basel, Abbott, AstraZeneca, Beckman Coulter, BRAHMS, Critical Diagnostics, Idorsia, Novartis, Ortho Clinical Diagnostics, Roche, Sanofi, Siemens and Singulex, as well as speaker/consulting honoraria or travel support from Acon, Amgen, Bayer, BMS, Boehringer Ingelheim, Idorsia, Medtronic, Novartis, Osler, Roche, Sanofi, Siemens and Singulex.