title: Sex Differences in Inappropriate ICD Device Therapies: MADIT-II and MADIT-CRT.
abstract: Approximately 10-20% of ICD recipients receive inappropriate device therapies. The purpose of this study was to compare the frequency of inappropriate therapies (IT) between men and women enrolled in MADIT II and MADIT-CRT, and assess for potential adverse outcomes.
  
  
  
  The electrograms for each ICD or CRT-D therapy, defined as either ATP or shock, were reviewed by adjudication committees for both studies. ICD therapy was considered inappropriate if it was delivered for reasons other than VT/VF. The rhythm triggering IT was categorized as atrial fibrillation/flutter, SVT, or inappropriate sensing when possible.
  
  
  
  One thousand nine hundred and fifty-four men and 556 women received ICD or CRT-D devices. The risk of IT was significantly lower in women than men (9.2% vs. 13.5%, P = 0.006). The most common cause of IT in men was atrial fibrillation (38%) and SVT in women (43%). Inappropriate shock was not associated with increased mortality in either women (HR 0.82 [95% CI 0.11-6.08]; P = NS) or men (HR 1.37 [95% CI 0.75-2.48]; P = NS) by multivariate analysis. Conversely, appropriate shock therapy strongly correlated with increased risk of death during subsequent post-shock follow-up in women (HR 5.99 [95% CI 2.75-13.02]; P < 0.0001) and men (HR 2.61 [95% CI 1.82-3.74]; P < 0.0001).
  
  
  
  Women experience significantly less IT than men, partially explained by the increased frequency of atrial fibrillation in men. IT was not associated with increased mortality in either sex. Appropriate shock therapy was a strong predictor of death in both, with women showing a 2-fold higher risk than men during post-shock long-term follow-up.
authors.affiliation: Cardiology Division, University of Colorado School of Medicine, Aurora, Colorado, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Tompkins
authors.affiliation: Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.affiliation: Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Bronislava
authors.initials: B
authors.lastname: Polonsky
authors.affiliation: Cardiology Division, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: James P
authors.initials: JP
authors.lastname: Daubert
authors.affiliation: Cardiology Division, Stanford University of Medicine, Palo Alto, California, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wang
authors.affiliation: Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.affiliation: Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.affiliation: Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, New York, USA.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology; D001282:Atrial Flutter / Q000175:diagnosis / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors; D012737:Sex Factors; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*
keywords: ICD shock; antitachycardia; cardiac resynchronization therapy; heart failure; inappropriate therapy; pacing; sex differences