title: Determinants of nonthoracotomy biphasic defibrillation.
abstract: The clinical variables affecting DFT for ICD systems are not completely determined, especially with regard to biphasic shocking devices. To distinguish which factors correlate with DFT, we examined data from patients who were enrolled in the Ventak P2/Endotak protocol. A total of 284 patients were enrolled in the study. Two patients had a DFT > 25 J and did not receive the device; 154 did not undergo stepdown to failure DFT testing. The remaining 128 patients had formal DFT testing and were suitable for analysis. Variables available for analysis included age, body surface area (BSA), LVEF, gender, lead configuration, primary arrhythmia, primary cardiac disease, and use of cardioactive medication. Data were evaluated using regression analysis, fitting DFT (range, 1-25 J, mean 11 +/- 5 J) as a function of each variable. As a univariate predictor. BSA was found to be significant in predicting DFT, but accounted for only 9% of the total variation on the DFT (P < 0.01, r = 0.3). This study suggests that DFT using a biphasic shocking waveform is modestly in fluenced by the BSA of the patient. Other specific factors, including LVEF, do not predict DFT.
authors.affiliation: Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Horton
authors.forename: R C
authors.initials: RC
authors.lastname: Canby
authors.forename: C A
authors.initials: CA
authors.lastname: Román
authors.forename: M L
authors.initials: ML
authors.lastname: Hull
authors.forename: S A
authors.initials: SA
authors.lastname: Kaye
authors.forename: M E
authors.initials: ME
authors.lastname: Jessen
authors.forename: R L
authors.initials: RL
authors.lastname: Page
mesh_terms: D000367:Age Factors; D000638:Amiodarone / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000628:therapy; D001830:Body Surface Area; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000379:methods*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004867:Equipment Design; D005260:Female; D005544:Forecasting; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012737:Sex Factors; D013318:Stroke Volume; D013499:Surface Properties; D013908:Thoracotomy; D016277:Ventricular Function, Left
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone