MYOCARDIAL INJURY-INDUCED BY RADIOFREQUENCY AND LOW-ENERGY ABLATION -A QUANTITATIVE STUDY OF CK ISOFORMS, CK-MB, AND TROPONIN-T CONCENTRATIONS

We conducted a prospective, controlled study to investigate the use of CK-MB concentration and newer methods such as troponin-T concentratio n and CK isoforms, in the assessment of myocardial damage caused by ra diofrequency current or low energy DC catheter ablation. The study pop ulation consisted of 3 consecutive patients who underwent low energy c atheter ablation, 28 consecutive patients subjected to radiofrequency ablation, and 4 patients who were subjected to radiofrequency energy a blation but also had external DC shocks for cardioversion of atrial fi brillation that occurred during the procedure. The control group compr ised eight subjects undergoing electrophysiological study. Prior to ab lation and at 30 minutes, 1, 2, 6, and 12 hours following the procedur e, serial blood samples were taken for measurement of troponin-T and C K-MB concentrations, and calculation of the MM3/MM1 and MB2/MB1 ratios . Troponin-T concentration was raised above normal in all patients sub jected to low energy ablation and in all but two patients subjected to radiofrequency ablation. Only 42% of all patients subjected to ablati on had at least one raised CK-MB concentration postablation. The MB2/M B1 ratio rr.as raised in all but two patients following radiofrequency or low energy ablation but it was also abnormal in the preablation sa mples in nine patients. The MM3/MM1 ratio failed to detect myocardial damage in 71% of all patients. There was a statistically significant d ifference between the control and patient groups regarding all four in dices of myocardial damage. Low energy ablation caused a significantly higher degree of myocardial damage compared with radiofrequency (RF); this effect could not be attributed to different numbers of total ene rgy discharges. Our results indicate that catheter ablation, regardles s of the mode of energy used, inflicts detectable injury upon the myoc ardium. This injury can be quantitated by using newer analytical techn iques, such as serial, postablation measurements of troponin-T concent ration.