title: Preliminary clinical results of a biphasic waveform and an RV lead system.
abstract: Biphasic defibrillation waveforms have provided a reduction in defibrillation thresholds in transvenous ICD systems. Although a variety of biphasic waveforms have been tested, the optimal pulse durations and tilts have yet to be identified. A multicenter clinical study was conducted to evaluate the performance of a new ICD biphasic waveform and new RV active fixation steroid eluting lead system. Fifty-three patients were entered into the study. Mean age was 63 years with a mean ejection fraction of 36.8%. Primary indication for implantation was monomorphic ventricular tachycardia alone (54.7%). Forty-eight patients (90.6%) were implanted with an RV shocking lead and active can alone as the anodal contact. The ICD can was the cathode. In four cases (7.5%), an additional SVC or CS lead was used due to a high DFT with the RV lead alone. In an additional case, a chronic SVC lead was used although the RV-Can DFT was acceptable. DFT for all cases at implant was 9.8 +/- 3.7 J. Repeat testing at 3 months for a subset of patients showed a reduction in DFT (7.4 +/- 3.0 J), P value = 0.03. Sensing and pacing characteristics of the RV lead system remained excellent during the study period (acute 0.047 +/- 0.005 ms at 5.4 V and 9.9 +/- 6.2 mV R wave; chronic 0.067 +/- 0.11 ms at 5.4 V and 9.3 +/- 5.4 mV R wave). It is concluded that this lead system provides good acute and chronic sensing and pacing characteristics with good DFT values in combination with this waveform.
authors.affiliation: Division of Cardiology, Ohio State University, Columbus, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Mehdirad
authors.forename: C J
authors.initials: CJ
authors.lastname: Love
authors.forename: M S
authors.initials: MS
authors.lastname: Stanton
authors.forename: S A
authors.initials: SA
authors.lastname: Strickberger
authors.forename: J L
authors.initials: JL
authors.lastname: Duncan
authors.forename: M W
authors.initials: MW
authors.lastname: Kroll
mesh_terms: D002303:Cardiac Output, Low / Q000150:complications; D009202:Cardiomyopathies / Q000150:complications; D002316:Cardiotonic Agents / Q000627:therapeutic use; D003327:Coronary Disease / Q000150:complications; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000379:methods*; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000628:therapy; D014693:Ventricular Fibrillation / Q000628:therapy
chemical_list: D002316:Cardiotonic Agents