Distribution of structural scar and deceleration zones in patients with VT and history of surgical valve intervention

Background

Although perivalvular regions are increasingly recognized as critical sites for ventricular tachycardia (VT) circuits, the relationship between late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) defined scar and functional slow-conduction areas identified by isochronal late activation mapping (ILAM) in this setting remains poorly defined.

Purpose

To describe the spatial relationship between ILAM deceleration zones (DZs), LGE-CMR scar and valvular structures in patients with VT and history of surgery for valvular heart disease.

Method

We retrospectively analyzed 17 consecutive patients with history of surgery for valvular heart disease undergoing VT ablation. For each patient we recorded valve diagnosis, intervention, severity, underlying cardiomyopathy, presence and etiology of LGE-CMR scar (infarct-related vs non-ischemic), number and location of ILAM DZs and the relation with induced VT. ILAM zones were considered to co-localize with LGE-CMR scar when located in the same ventricular segment and classified as perivalvular when adjacent to a valve annulus or prosthesis on the electroanatomical map.

Results

Patients were 63.9 years old [58.4-69.4], and 13/17 (76.5%) were male. Valve interventions involved the aortic valve in 10 patients, the mitral valve in 7 and the tricuspid valve in 4. Ischemic heart disease was present in 7/17 (41.2%). LGE-CMR identified scar in 16/17 patients (94.1%), yielding 32 scar regions (2 [1–3] per patient). 5/32 (15.6%) were infarct-related and 27/32 (84.3%) non-ischemic or not attributable to prior infarction. DZs were present in 16/17 patients, being 28 in total (2 [1–2] per DZ-positive patient) distributed across anterior (25%), inferior (25%), lateral (14%) and septal/other (36%) left ventricular regions.

Overall, 26/28 (92.8%) ILAM zones co-localized with LGE-defined scar, including 6/28 (21.4%) on infarct-related and 20/28 (71.4%) on non-ischemic scar, while 2/28 (7.1%) occurred in segments without detectable LGE. At least one ILAM DZ overlapped LGE scar in 15/16 (93.6%) DZ-positive patients. Peri-valvular involvement was frequent: 11/28 (39.2%) ILAM zones and 10/16 (62.5%) DZ-positive patients had at least one perivalvular ILAM DZ. Among peri-valvular DZs, 9/11 (81.8%) co-localized with non-ischemic scar and none with infarct-related scar.

Conclusion

In this cohort of patients with valvular heart disease undergoing VT ablation, DZ were predominantly located within or at the border of LGE-defined fibrosis, mainly of non-ischemic origin, and frequently clustered around valvular structures. These findings support perivalvular fibrosis as an important functional substrate in this population and suggest that ILAM-guided strategies targeting perivalvular regions may be valuable. Larger, prospective studies are warranted to confirm these observations.Descriptive analysis of the cohortSummary of the main results