Preinterventional quantification of dense scar or borderline zone in patients undergoing ventricular tachycardia ablation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. INTRODUCTION: This study sought to examine the prognostic role of quantifying areas of interest in preinterventional cardiac magnetic resonance (CMR) in patients with structural heart disease (SHD) referred for ablation of ventricular tachycardia (VT). BACKGROUND: The role of preinterventional CMR for the identification of scar areas, borderline zones and reentry channels in the ventricles has been well established. Whether the burden of dense scar or borderline tissue has a prognostic impact on the acute and the long-term ablation outcome in SHD patients is disputed. METHODS AND RESULTS: We investigated 185 patients with SHD undergoing preinterventional CMR prior to VT-ablation. 38 patients were excluded because of poor imaging quality, leaving a cohort of 147 patients with positive late enhancement (LGE) imaging (mean age 62 years, 47% non-ischemic cardiomyopathy, mean left ventricle ejection fraction 38%, 96% with implanted ICD). The cohort was divided in ischemic (ICM) and non-ischemic (NICM) cardiomyopathy group and the results regarding burden of overall scar tissue, dense scar, borderline zone, as well as clinical and procedural characteristics, acute and long-term results of the two groups were compared. The ICM patients had more advanced NYHA stadium (p = 0.046), reduced left ventricular ejection fraction (LV-EF, p <0.001) and higher left ventricular enddiastolic volume (LVEDV, p <0.001). The NICM patients were more often under antiarrhythmic therapy (p = 0.005) and underwent more frequently epicardial ablation (p <0.001). Although the overall scar burden war higher in ICM patients (p <0.001), the groups showed no significant difference in borderline zone burden (p = 0.580). Furthermore, the two groups had similar results in number of inducible VTs (p = 0.054) and VT inducibility at the end of the procedure (p = 0.121). Nevertheless, the NICM group underwent overall more ablation procedures during the 19-month follow up (p = 0.023). Both groups showed similar results regarding assist device implantation, heart transplantation or death until the end of the follow up (p = 0.192). CONCLUSION: While quantification of the scar tissue and the borderline zone is feasible in ICD patients with SHD, the scar or the borderline zone burden were not predictive of the VT ablation outcome.