Scientific Publications Database

Article Title: Association between transthoracic impedance and electrical cardioversion success with biphasic defibrillators: An analysis of 1055 shocks for atrial fibrillation and flutter
Authors: Sadek, Mouhannad M.; Chaugai, Varsha; Cleland, Mark J.; Zakutney, Timothy J.; Birnie, David H.; Ramirez, F. Daniel
Journal: CLINICAL CARDIOLOGY Volume 41 Issue 5
Date of Publication:2018
Abstract:
BackgroundThe relevance of transthoracic impedance (TTI) to electrical cardioversion (ECV) success for atrial tachyarrhythmias when using biphasic waveform defibrillators is unknown.HypothesisTTI is predictive of ECV success with contemporary defibrillators.MethodsDe-identified data stored in biphasic defibrillator memory cards from ECV attempts for atrial fibrillation (AF) or atrial flutter (AFL) over a 2-year period at our center were evaluated. ECV success, defined as arrhythmia termination and1 sinus beat, was adjudicated by 2 blinded cardiac electrophysiologists. The association between TTI and ECV success was assessed via Cochrane-Armitage trend and Spearman rank correlation tests, as well as simple and multivariable logistic regression. The influence of TTI on the number of shocks and on cumulative energy delivered per patient was also examined.Results703 patients (593 with AF, 110 with AFL) receiving 1055 shocks were included. Last shock success was achieved in 88.0% and 98.2% of patients with AF and AFL, respectively. In patients with AF, TTI was positively associated with last shock failure (P-trend=0.019), the need for multiple shocks (P-trend<0.001), and cumulative energy delivered (=0.348; P<0.001). After adjusting for first shock energy, 10- increments in TTI were associated with odds ratios of 1.36 (95% CI: 1.24-1.49) and 1.22 (95% CI: 1.09-1.37) for first and last shock failure, respectively (P<0.001 for both).ConclusionsAlthough contemporary defibrillators are designed to compensate for TTI, this variable continues to be associated with ECV failure in patients with AF. Strategies to lower TTI during ECV for AF may improve procedural success.