Direct current cardioversion, which produces electrical energy, is highly effective for the termination of cardiac arrhythmia and sometimes is indicated in patients with coronary artery stents due to arrhythmias. Only a few reports have been published describing the potential adverse interactions between foreign bodies and electrical cardioversion. The aim of this animal study was to investigate the acute effect of repeated external defibrillation on coronary artery tissue and adjacent myocardium at the implantation site of coronary stents. Custom-made stainless steel stents were implanted in the coronary arteries of 7 dogs. Rapid ventricular pacing was performed to induce ventricular fibrillation. Defibrillation was achieved [5 J/kg; n=2 and 8 J/kg; n=3]. In 2 animals, coronary stent was implanted but defibrillation was not performed [control group]. The animal’s heart were excised and sent for microscopic examination. The light and electron micrographs of heart muscles showed no histological and ultrastructural changes in defibrillated and control dogs. It is concluded that nickel coating provides good resistance to heat in coronary stents and repeated defibrillation does not cause histopathological changes typical of thermal injury at the implantation site of coronary stent.