Multimodality Imaging and Pace-Mapping Patterns in Patients With Cardiac Sarcoidosis and Ongoing Inflammation...

The arrhythmogenesis in cardiac sarcoidosis (CS) is poorly understood. The recent ability to register fluorodeoxyglucose (FDG)-avid (FDG+) areas from positron emission tomography studies enables us to correlate the location of areas containing late gadolinium enhancement (LGE+) on cardiac magnetic resonance imaging with FDG-avid areas.

This study sought to characterize ventricular tachycardia (VT) target sites with respect to FDG uptake and to correlate with VT recurrence post-VT ablation.

In 14 patients (4 women; age 55 ± 11 years; ejection fraction 43% ± 14%) with definite CS and active inflammation referred for VT ablation, positron emission tomography and cardiac magnetic resonance findings were registered to electroanatomic maps. VT target areas were identified with pace- and entrainment-mapping, and conduction patterns were assessed based on different stimulus-QRS intervals of VA target sites.

A total of 43 distinct VTs with 59 VT target sites were identified. A total of 88% of the identified VT target sites were in LGE+ areas, whereas 71% were in FDG+ areas. The LGE+ and FDG+ sites colocalized at 59% of all VT target sites. VT exit sites were identified for 42 of 59 VT target sites and nonexit sites for 17 of 59 VT target sites. VT exit sites were associated with FDG+ areas. During a follow-up time of 32 ± 33 months, 6 patients in whom only VT exit sites were identified had a higher VT recurrence rate than patients (n = 8) in whom both nonexit sites and exit sites for individual VTs were identified (100% vs 25%; P = 0.01), indicating that ablation at both exit and nonexit sites yielded superior results.

In patients with CS and active inflammation, most VT target sites were confined to LGE+ and FDG+ areas. VT exit sites were associated with FDG+ areas. Patients in whom only VT exit sites were identified had higher VT recurrences.