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Determinants of First‐Shock Success for Atrial Implantable Cardioverter Defibrillators
Author(s) -
SWERDLOW CHARLES D.,
SCHWARTZMAN DAVID,
HOYT ROBERT,
BAILIN STEVEN J.,
KOEHLER JODI L.,
WARMAN EDUARDO N.
Publication year - 2002
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2002.00347.x
Subject(s) - medicine , cardiology , defibrillation , atrial fibrillation , shock (circulatory) , sinus rhythm , univariate analysis , defibrillation threshold , confidence interval , ambulatory , relative risk , coronary sinus , multivariate analysis
Atrial Defibrillation.Introduction: The aim of this study was to identify determinants of first‐shock success for defibrillation of spontaneous atrial fibrillation (AF) in ambulatory patients with an atrial implantable cardioverter defibrillator (ICD). The determinants of first‐shock success in ambulatory patients with atrial ICDs are unknown. Methods and Results: We used the generalized estimating equation method to analyze determinants of first‐shock success in 50 consecutive atrial ICD recipients in whom DFT+ (weakest shock that defibrillates on two consecutive trials) was determined at implant and spontaneous AF was shocked with shock strength > 2 × DFT+. DFT+ was 6.2 ± 3.1 J . Of 470 first shocks, 407 were successful (generalized estimating equation 85%, confidence interval 79% to 90%). Determinants of first‐shock success were use of coronary sinus electrode (univariate P = 0.02 ; multivariate P < 0.001 , relative risk 5.0), absence of a Class III antiarrhythmic drug (univariate P = 0.06 ; multivariate P < 0.001, relative risk 3.2), absence of early recurrence of atrial fibrillation (ERAF; univariate P = 0.06 ; multivariate P = 0.02 , relative risk 2.9), and longer duration of AF prior to shock > 3 hours (univariate: P = 0.02 ; multivariate P = NS ). Sinus rhythm > 1 minute persisted after 93% of first shocks in patients without documented ERAF but after only 58% of shocks in patients with documented ERAF ( P < 0.001 ). Conclusion: Reducing ERAF is critical to achieving a clinically acceptable rate of persistent sinus rhythm after first shocks. For first shocks > 2 × DFT+, success is not increased by programming stronger shocks. Early cardioversion does not increase first‐shock success.