title: Role of defibrillation threshold testing in the contemporary defibrillator patient population.
abstract: BACKGROUND
  Defibrillation threshold (DFT) testing has been performed to prove functionality of the implantable cardioverter defibrillator (ICD). Over the past years it has become increasingly controversial because of possible morbidity and mortality. The goal of this study was to determine unsuccessful shock testing and report strategies used to overcome these problems.
  
  
  RESULTS
  A total of 314 patients with a de novo implantation of an ICD and 127 patients receiving a generator exchange were identified retrospectively. All patients underwent defibrillation threshold testing after induction of VF using a low-energy T-wave shock during the intervention, 2 shock tests after de novo implantations, 1 after generator change. A safety margin of 10 J or more was requested. Seven (2.3%) patients in the de novo group and 2 patients (1.4%) in the generator exchange group could not be defibrillated using the standard approach. All of those patients had either chronic amiodarone therapy, secondary prevention or a cardiac resynchronization therapy device (CRT). In univariate analysis, amiodarone therapy, dilated cardiomyopathy, and lower ejection fraction were predictors of failure.
  
  
  CONCLUSIONS
  Our study's results as well as a review of the current literature favor shock testing, especially in patients with specific risk factors as mentioned above.
authors.affiliation: Department of Internal Medicine, University of Basel Hospital, Basel, Switzerland.
authors.forename: Annina S
authors.initials: AS
authors.lastname: Vischer
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kühne
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Beat A
authors.initials: BA
authors.lastname: Schaer
mesh_terms: D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D058409:Cardiac Resynchronization Therapy Devices; D002311:Cardiomyopathy, Dilated / Q000150:complications; D017147:Defibrillators, Implantable; D020878:Device Removal; D004554:Electric Countershock / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac; D004869:Equipment Safety; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D016277:Ventricular Function, Left
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone