Electrophysiology studies in patients undergoing ICD implantation: findings from the NCDR®.
BACKGROUND
Electrophysiology studies (EPS) have historically played a role in sudden death risk stratification. More recent studies point to the left ventricular ejection fraction (EF) as a guide to implantable cardioverter defibrillators (ICD) implantation. The extent of EPS use in patients undergoing ICD implantation in the current era remains unknown.


METHODS
Patients undergoing de novo ICD implantation in the ICD Registry between September 2006 and March 2009 who also underwent EPS within 30 days before implant were compared to the remaining cohort to identify clinical characteristics that correlated with EPS performance. Multivariate models were generated using hierarchical logistic regression analysis.


RESULTS
EPS were performed in 33,786 of 275,273 patients. Those undergoing EPS were more likely to have had a history of syncope, family history of sudden death, lack of congestive heart failure, narrower QRS intervals, and higher EF. Overall, 63.9% of EPS were performed in patients receiving primary prevention ICDs. Ventricular tachyarrhythmias were induced in 46.1% of primary prevention and 54.2% of secondary prevention ICD recipients. Monomorphic ventricular tachycardia was the most common type of arrhythmia induced in both groups. Complication rates were not higher in those undergoing EPS.


CONCLUSIONS
EPS were performed predominantly in patients with borderline or less well-defined risk factors for sudden death. Ventricular arrhythmias induced from EPS were not uncommon and may help identify individuals at higher risk for future ICD therapies. Efforts to better define the role of EPS in patients undergoing ICD implantation should be considered.
Section of Cardiac Electrophysiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. alcheng@jhmi.edu
Alan
A
Cheng
Yongfei
Y
Wang
Ronald D
RD
Berger
Hugh
H
Calkins
Alfred E
AE
Buxton
Jeptha P
JP
Curtis
Rachel
R
Lampert
D000368:Aged; D000369:Aged, 80 and over; D002319:Cardiovascular System / Q000503:physiopathology; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D017147:Defibrillators, Implantable / Q000009:adverse effects / Q000706:statistics & numerical data*; D022062:Electrophysiologic Techniques, Cardiac / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D013318:Stroke Volume / Q000502:physiology; D013575:Syncope / Q000453:epidemiology / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000517:prevention & control / Q000628:therapy; D016896:Treatment Outcome