P5695Catheter ablation of ventricular tachycardia in patients with acute vs. previous myocarditis

Abstract

Abstract Background Ventricular tachycardias (VT) may occur late after myocarditis, as well as in the acute inflammatory phase of the disease. However, the role of catheter ablation (CA) in preventing VT recurrences in patients with acute (AM) vs. previous myocarditis (PM) has never been investigated so far. Purpose To evaluate the results of CA performed in patients presenting with VA and biopsy-proved myocarditis at different inflammatory stages. Methods We enrolled 46 consecutive patients (74% males, mean age 43±12y, mean LVEF 46±9%) with myocarditis and VT at index hospitalization. Based on endomyocardial biopsy and cardiac magnetic resonance (CMR) results, the patients were divided into AM and PM groups: in AM group, myocarditis was biopsy-proved, according to the ESC criteria; PM patients had a history of biopsy-proved myocarditis more than 12 months before, with no current signs of active inflammation (negative biopsy according to the ESC criteria; nonischaemic LGE at CMR with negative Lake-Louise criteria; absence of unexplained troponin abnormalities). ICD were implanted upon clinical indications. All of the patients underwent electroanatomical mapping (EAM) and VT CA. During 3 (2.5–3.5)y FU, VT recurrences were evaluated by 2/y Holter ECG and ICD interrogation. Results At baseline, 23 patients (50%) had AM, and 23 PM. Overall, 16 AM and 21 PM patients underwent ICD implant (p=n.s.). The clinical VT was monomorphic in 22 AM and 23 PM patients, respectively (p=n.s.) with a dominant right-bundle branch block with superior axis (RS) morphology in both groups (16 AM vs. 17 PM cases, p=n.s.). However, RS morphology was associated with left ventricular inferoposterior LGE at CMR in 9/16 AM vs. 17/17 PM patients (p=0.003). Similarly, inferoposterior localization of low-voltage areas at EAM was found in 11/16 AM vs. 17/17 PM patients (p=0.018). Furthermore, CMR showed a greater LGE transmural extension in AM patients (65±19%) as compared to PM ones (40±25%, p<0.001). Epicardial EAM and CA were performed in 14 AM vs. 15 PM patients, with endocardial-only approach adopted in the remaining cases (p=n.s.). VT CA was defined as successful (class A) in all of the subjets. However, during FU VT recurrences were documented in 7/23 AM vs. 0/23 PM patients (p=0.009). Four AM cases underwent redo CA late after myocarditis (1.5±0.3y after index hospitalization), with no further VT recurrences in FU. Conclusion In myocarditis patients presenting with VT, CA results are significantly better in PM cases as compared to AM ones. These findings are consistent with the different underlying substrate, and suggest the best role for ablation strategy after myocarditis healing. Acknowledgement/Funding None