Cardiac troponin I and cardiac enzymes after electrophysiologic studies, ablations, and defibrillator implantations

Troponins I, C, and T form a complex that regulates the calcium-mediated in teraction of actin and myosin in skeletal muscle. Three isoforms of troponi n I have been identified: cardiac troponin I, slow twitch skeletal troponin I, and fast twitch troponin I.(1,2) Monoclonal antibodies for cardiac trop onin I are markers with high specificity for cardiac injury.(3) Cardiac tro ponin I assays have >90% sensitivity and 100% specificity for the diagnosis of acute myocardial infarction.(4) Cardiac troponin I is abnormal at 4 to 8 hours after the onset of chest pain, peaks at 12 to 16 hours, and remains elevated for 5 to 9 days.(5) Recent studies have reported that cardiac tro ponin I does not increase after external electrical cardioversion.(6,7) Eva luation of cardiac troponin I measurements after electrophysiologic studies , ablations, and defibrillator implantations have not been examined. This s tudy was designed to assess cardiac troponin I and other cardiac enzyme lev els after electrophysiologic studies, ablations, and defibrillator implanta tions.