Effects of pacing sites on substrate mapping using decrement-evoked potential mapping for scar-related ventricular tachycardia

BACKGROUND: The ventricular tachycardia (VT) substrate map is influenced by the rhythm during mapping. OBJECTIVE: This study aimed to elucidate the effects of different pacing sites on decrement-evoked potential (DEEP) mapping of scar-related VT in patients with cardiomyopathy. METHODS: Patients with ischemic cardiomyopathy or nonischemic cardiomyopathy who underwent substrate mapping and ablation for scar-related VT were included. DEEP mapping was performed during right ventricular apical (RVA) and left ventricular outflow tract (LVOT) pacing. We analyzed the characteristics of deceleration zones (DZs) from the DEEP maps obtained during RVA and LVOT pacing. RESULTS: A total of 20 patients (age 61.1 ± 17.7 years; 17 males; 11 with ischemic cardiomyopathy and 9 with nonischemic cardiomyopathy) were studied. The numbers of pacemap-matching DZs identified from the RVA S1, RVA S2, LVOT S1, and LVOT S2 maps were 0.74 ± 0.87, 1.28 ± 1.13, 1.00 ± 0.91, and 1.44 ± 1.20, respectively. 2 DZs were visible only during RVA pacing because they were parallel to the conduction direction. 7 DZs were visible only during LVOT pacing-5 DZs were parallel to the conduction direction, and 2 DZs were located at the wavefront collision area. S2 pacing and LVOT pacing were useful for finding more DZs in 41.2% and 41.2% of patients, respectively. During a mean follow-up of 10.9 ± 3.6 months, VT recurred in 30.0% of patients. CONCLUSION: A high number of pacemap-matching DZs can be identified using 2-site pacing DEEP mapping.