ENDOCARDIAL AND EPICARDIAL ABLATION GUIDED BY NONSURGICAL TRANSTHORACIC EPICARDIAL MAPPING TO TREAT RECURRENT VENTRICULAR-TACHYCARDIA

Nonsurgical Epicardial Ablation. Introduction: An epicardial site of o rigin of ventricular tachycardia (VT) may explain unsuccessful endocar dial radiofrequency (RF) catheter ablation, A new technique to map the epicardial surface of the heart through pericardial puncture was pres ented recently and opened the possibility of using epicardial mapping to guide endocardial ablation or epicardial catheter ablation, We repo rt the efficacy and safety of these two approaches to treat 10 consecu tive patients with VT and Chagas' disease. Methods and Results: Epicar dial mapping was carried out with a regular steerable catheter introdu ced into the pericardial space, An epicardial circuit was found in 14 of 18 mapable VTs induced in 10 patients, Epicardial mapping was used to guide endocardial ablation in 4 patients and epicardial ablation in 6, The epicardial earliest activation site occurred 107 +/- 60 msec e arlier than the onset of the QRS complex, At the epicardial site used to guide endocardial ablation, earliest activation occurred 75 +/- 55 msec before the QRS complex, Epicardial mid-diastolic potentials and/o r continuous electrical activity were seen in 7 patients, After 4.8 +/ - 2.9 seconds of epicardial RF applications, VT was rendered noninduci ble, Hemopericardium requiring drainage occurred in 1 patient; 3 other s developed pericardial friction without hemopericardium. Patients rem ain asymptomatic 5 to 9 months after the procedure, Interruption durin g endocardial pulses occurred after 20.2 +/- 14 seconds (P = 0.004), b ut VT was always reinducible and the patients experienced a poor outco me. Conclusion: Epicardial mapping does not enhance the effectiveness of endocardial pulses of RF, Epicardial applications of RF energy can safely and effectively treat patients with VT and Chagas' disease.