This study was supported by Cameron Health, Inc. (Boston Scientific) and NIH grant HL 085370.
Evaluation of Acute Cardiac and Chest Wall Damage after Shocks with a Subcutaneous Implantable Cardioverter Defibrillator in Swine
Version of Record online: 28 MAY 2013
©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.
Pacing and Clinical Electrophysiology
Volume 36, Issue 10, pages 1265–1272, October 2013
How to Cite
KILLINGSWORTH, C. R., MELNICK, S. B., LITOVSKY, S. H., IDEKER, R. E. and WALCOTT, G. P. (2013), Evaluation of Acute Cardiac and Chest Wall Damage after Shocks with a Subcutaneous Implantable Cardioverter Defibrillator in Swine. Pacing and Clinical Electrophysiology, 36: 1265–1272. doi: 10.1111/pace.12173
- Issue online: 8 OCT 2013
- Version of Record online: 28 MAY 2013
- Manuscript Accepted: 2 APR 2013
- Manuscript Revised: 21 MAR 2013
- Manuscript Received: 24 AUG 2012
- Cameron Health, Inc. (Boston Scientific) and NIH. Grant Number: HL 085370
- implantable cardioverter defibrillator;
- troponin I;
- creatine kinase;
A subcutaneous implantable cardioverter defibrillator (S-ICD) could ease placement and reduce complications of transvenous ICDs, but requires more energy than transvenous ICDs. Therefore we assessed cardiac and chest wall damage caused by the maximum energy shocks delivered by both types of clinical devices.
During sinus rhythm, anesthetized pigs (38 ± 6 kg) received an S-ICD (n = 4) and five 80-Joule (J) shocks, or a transvenous ICD (control, n = 4) and five 35-J shocks. An inactive S-ICD electrode was implanted into the same control pigs to study implant trauma. All animals survived 24 hours. Troponin I and creatine kinase muscle isoenzyme (CK-MM) were measured as indicators of myocardial and skeletal muscle injury. Histopathological injury of heart, lungs, and chest wall was assessed using semiquantitative scoring.
Troponin I was significantly elevated at 4 hours and 24 hours (22.6 ± 16.3 ng/mL and 3.1 ± 1.3 ng/mL; baseline 0.07 ± 0.09 ng/mL) in control pigs but not in S-ICD pigs (0.12 ± 0.11 ng/mL and 0.13 ± 0.13 ng/mL; baseline 0.06 ± 0.03 ng/mL). CK-MM was significantly elevated in S-ICD pigs after shocks (6,544 ± 1,496 U/L and 9,705 ± 6,240 U/L; baseline 704 ± 398 U/L) but not in controls. Electrocardiogram changes occurred postshock in controls but not in S-ICD pigs. The myocardium and lungs were histologically normal in both groups. Subcutaneous injury was greater in S-ICD compared to controls.
Although CK-MM suggested more skeletal muscle injury in S-ICD pigs, significant cardiac, lung, and chest wall histopathological changes were not detected in either group. Troponin I data indicate significantly less cardiac injury from 80-J S-ICD shocks than 35-J transvenous shocks.