| Abstract | OBJECTIVES: The purpose of this study was to evaluate the efficacy of a totally subcutaneous, anteroposterior defibrillation shock pathway using a long time-constant shock waveform that emulates a proposed device having approximately twice the capacitance and thus twice the available energy of traditional transvenous devices. BACKGROUND: A non-transvenous defibrillation system potentially offers advantages over a transvenous system including simplification of the implant procedure and reduction of the impact of device complications by eliminating the need to place a lead within the heart. Previous non-transvenous defibrillation efficacy studies have been reported using anterolateral and anterior-anterior shock vectors. An external anteroposterior shock vector has demonstrated superior efficacy compared to anterolateral shock vectors but a prospective study on an anteroposterior shock vector with implanted electrodes has not been previously reported. METHODS: The non-transvenous shock vector consisted of an anterior low pectorally-placed active can emulator electrode and a posterior subcutaneous coil electrode. The shock waveform was a biphasic with 50% tilt per phase and a time constant of decay of 12 ms. Defibrillation efficacy was characterized using a step-down defibrillation threshold protocol (35 J, 25 J, 15 J). RESULTS: A total of 33 patients with standard ICD indications were enrolled in the study with 32 fully completing the protocol. The patient population was 69% male, with a mean age of 59 +/- 12 years. Mean ejection fraction was 27 +/- 12%. Of the 32 patients tested, 26 patients (81%) were successfully defibrillated at 35 J or less, 18 patients were defibrillated at 25 J or less and 9 patients were successfully defibrillated at 15 J. CONCLUSIONS: Defibrillation using a long time-constant waveform delivered through an anteroposterior non-transvenous pathway including a pectoral active can emulator electrode and a posterior subcutaneous coil electrode is feasible with over 80% of patients defibrillated successfully using 35 J or less. |
| Authors | Randy Lieberman, William J Havel, Eric Rashba, Paul J DeGroot, Kurt Stromberg, Stephen R Shorofsky
(Affiliation: Harper Hospital, Detroit, Michigan, USA. rlieberm at dmc.org)
|
| Journal | Heart rhythm : the official journal of the Heart Rhythm Society
(Heart Rhythm)
Vol. 5
Issue 1
Pg. 28-34
(Jan 2008)
ISSN: 1547-5271 United States |
| PMID | 18053770
(Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
|
| Topics |
- Acute Disease
- Age Factors
- Death, Sudden, Cardiac
- Defibrillators, Implantable
- Electric Countershock
(methods)
- Electrodes
- Female
- Heart Ventricles
(pathology)
- Humans
- Male
- Middle Aged
- Prospective Studies
- Stroke Volume
- Ventricular Fibrillation
(mortality, therapy)
|
