The association between defibrillation shock energy and acute cardiac damage in patients with implantable cardioverter defibrillators

Abstract

BackgroundThe aim of this study was to establish a minimally invasive defibrillation testing (DT) protocol for patients with implantable cardioverter defibrillators (ICDs). MethodsTwo different energy DTs were performed, immediately after (15J-DT) and 7 days after (≤10J-DT) device implantation, in 20 consecutive ICD implantation patients. Cardiac-troponin T (c-TNT) and heart-type fatty acid binding protein (H-FABP) levels were measured before implantation, 2h after implantation, and 1 day after each DT. For an additional 122 patients with ICD, we retrospectively analyzed 203 DTs immediately and 7 days after device implantation. ResultsSerum c-TNT levels were significantly elevated 2h after 15J-DT [0.008 (0.004–0.019) vs. 0.053 (0.037–0.068)ng/mL, p<0.001], but not ≤10J-DT [0.007 (0.004–0.018)ng/mL]. Similarly, serum H-FABP levels were significantly elevated 2h after 15J-DT (2.9±1.5 vs. 6.4±3.4ng/mL, p<0.001), but not ≤10J-DT (2.7±1.5ng/mL). The changes in c-TNT and H-FABP levels between baseline and 2h after DT were significantly greater for 15J-DT compared with ≤10J-DT [c-TnT: 0.039 (0.029–0.060) vs. 0 (0–0.003)ng/mL, p<0.001; H-FABP: 3.6±2.8 vs. −0.16±1.1ng/mL, p<0.001]. The success rates of the initial shocks delivered for ventricular fibrillation were no different between ≤10J-DT (85% [78/92]) and ≥15J-DT (92% [103/111]). ConclusionsElevated levels of myocardial damage markers such as c-TNT and H-FABP were not found after ≤10J-DT. In addition, an acceptable success rate was confirmed in ≤10J-DT.