The Effect of Direct Current Transthoracic Countershock on Human Myocardial Cells Evidenced by Creatine Kinase and Lactic Dehydrogenase Isoenzymes.

Direct current transthoracic countershock has been used successfully for years to terminate hemodynamically significant cardiac dysrhythmias. Hazards associated with countershock have been reported on animal and human subjects, however, these results do not seem to be consistent in the literature. The purpose of this study was to determine if DC-countershock could harm myocardial cells leading the liberation of cardiac specific isoenzymes into the blood. The results of this study suggest that DC-countershock is not associated with myocardial damage and that its use in terminating hemodynamically significant dysrhythmias is relatively safe under the conditions outlined by this study. The amount of countershock delivered should be tempered with judgment regarding the body surface area and transthoracic resistance of the patient. Consecutive countershocks should be delivered within minutes of each other. Waiting 4 hours between countershocks coupled with the infusion of procainamide, can lead to a rise in skeletal muscle creatine kinase, suggesting that injury can occur to skeletal muscle tissue following split dose countershock.