Electroanatomic substrate and outcome of catheter ablative therapy for ventricular tachycardia in setting of right ventricular cardiomyopathy

Background - To gain insight into the pathogenesis of right ventricular ( RV) cardiomyopathy and ventricular tachycardia (VT), we determined the clinical and electroanatomic characteristics and outcome of ablative therapy in consecutive patients with ( 1) RV dilatation, ( 2) multiple left bundle-branch block (LBBB) -type VTs, and (3) an abnormal endocardial substrate defined by contiguous electrogram abnormalities. Methods and Results - All 21 patients had detailed RV bipolar electrogram voltage mapping. Eighteen patients had simultaneous left ventricular (LV) mapping, including all 4 patients with right bundle-branch block (RBBB) VT. VT was ablated in 19 patients by use of focal and/or linear lesions with irrigated-tip catheters in 10 of 19 patients. Eighteen patients were men, age 47 +/- 18 years, and none had a family history of RV dysplasia. RV volume was 223 +/- 89 cm(3). Electrogram abnormalities extended from perivalvular tricuspid valves ( 5 patients), pulmonic valves ( 6 patients), or both valves ( 10 patients). Electrogram abnormalities always involved free wall, spared the apex, and included the septum in 15 patients (71%). The area of abnormality was 55 +/- 37 cm(2) (range, 12 to 130 cm(2)) and represented 34 +/- 19% of the RV. In 52 of 66 LBBB VTs, the origin was from the RV perivalvular region. LV perivalvular low-voltage areas noted in 5 patients were associated with a RBBB VT origin. No VT recurred after ablation in 17 patients ( 89%) during 27 +/- 22 months. Conclusions - In patients with RV cardiomyopathy and VT, ( 1) perivalvular electrogram abnormalities represent the commonly identified substrate and source of most VT, ( 2) LV perivalvular endocardial electrogram abnormalities and VT can occasionally be identified, and ( 3) aggressive ablative therapy provides long-term VT control.