Nonsymptomatic myocardial injury after radiofrequency and cryoablation: a study of children and patients with congenital heart disease.

The aim of this study was to investigate the degree of myocardial injury following catheter radiofrequency (RF) ablation (RFA) or cryoablation and its clinical significance in children and patients with congenital heart disease. Cardiac troponin T (cTnT) or cardiac troponin I (cTnI), creatine kinase (CK), and its cardiac isoenzyme MB (CK-MB) were measured in 269 patients who underwent catheter ablation (216 RFA, 53 cryoablation) just before the procedure and again 6 hours after the end of the procedure. Follow-up studies included echocardiography and 12 lead electrocardiographics (ECGs). No clinical, ECG, nor ECG signs of ischemia were detected. Biomarkers were increased in 57.7-75.5 %. A linear regression analysis illustrated the ablation target site and the number of RF applications as a function of higher cTnI and cTnT levels, with the maximum increase due to ventricular ablation and higher numbers of RF applications. No significant difference in cTnT levels after RFA or cryoablation were observed for AV nodal reentrant tachycardia procedures and no significant differences were observed after nonirrigated tip or irrigated tip RFA in atrial wall or ventricular wall ablation. Elevations in both troponin T and troponin I levels were commonly observed after ablation, especially in ventricular wall ablation as well as with increasing numbers of radiofrequency applications. However, unlike in patients with acute coronary syndrome, these elevated levels had no specific significance. Reference values for each ablation target site were proposed in order to potentially detect additional subclinical injuries to the coronary arteries.