Predictors of an inadequate defibrillation safety margin at ICD implantation: insights from the National Cardiovascular Data Registry.

Abstract

BACKGROUND:

Defibrillation testing is often performed to establish effective arrhythmia termination, but predictors and consequences of an inadequate defibrillation safety margin (DSM) remain largely unknown.

OBJECTIVES:

The aims of this study were to develop a simple risk score predictive of an inadequate DSM at implantable cardioverter-defibrillator (ICD) implantation and to examine the association of an inadequate DSM with adverse events.

METHODS:

A total of 132,477 ICD Registry implantations between 2010 and 2012 were analyzed. Using logistic regression models, factors most predictive of an inadequate DSM (defined as the lowest successful energy tested <10 J from maximal device output) were identified, and the association of an inadequate DSM with adverse events was evaluated.

RESULTS:

Inadequate DSMs occurred in 12,397 patients (9.4%). A simple risk score composed of 8 easily identifiable variables characterized patients at high and low risk for an inadequate DSM, including (with assigned points) age <70 years (1 point); male sex (1 point); race: black (4 points), Hispanic (2 points), or other (1 point); New York Heart Association functional class III (1 point) or IV (3 points); no ischemic heart disease (2 points); renal dialysis (3 points); secondary prevention indication (1 point); and ICD type: single-chamber (2 points) or biventricular (1 point) device. An inadequate DSM was associated with greater odds of complications (odds ratio: 1.22; 95% confidence interval: 1.09 to 1.37; p = 0.0006), hospital stay >3 days (odds ratio: 1.24; 95% confidence interval: 1.19 to 1.30; p < 0.0001), and in-hospital mortality (odds ratio: 1.96; 95% confidence interval: 1.63 to 2.36; p < 0.0001).

CONCLUSIONS:

A simple risk score identified ICD recipients at risk for an inadequate DSM. An inadequate DSM was associated with an increased risk for in-hospital adverse events.

• Authors: Jonathan C Hsu, Gregory M Marcus, Sana M Al-Khatib, Yongfei Wang, Jeptha P Curtis, Nitesh Sood, Matthew W Parker, Jeffrey Kluger, Rachel Lampert, Andrea M Russo
• Journal: Journal of the American College of Cardiology (J Am Coll Cardiol) Vol. 64 Issue 3 Pg. 256-64 (Jul 22 2014) ISSN: 1558-3597 [Electronic] United States
• PMID: 25034061 (Publication Type: Journal Article, Observational Study, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Topics

• Adult
• Aged
• Cardiovascular Diseases (diagnosis, therapy)
• Cohort Studies
• Databases, Factual (trends)
• Defibrillators, Implantable (adverse effects, trends)
• Electric Countershock (adverse effects, trends)
• Female
• Humans
• Length of Stay (trends)
• Male
• Middle Aged
• Predictive Value of Tests
• Registries
• Risk Factors