Dynamic changes in the signal-averaged electrocardiogram are associated with the long-term outcomes after ablation of ischemic ventricular tachycardia

Abstract

Purpose Signal-averaged ECG (SAECG) can detect inhomogeneous myocardial conduction in patients presenting with ventricular tachycardia (VT) after myocardial infarction. Radiofrequency ablation (RFCA) aims at elimination of the endocardial late potentials and non-inducibility of VT. Previously, we demonstrated that abnormal SAECG at baseline can return to normal after a successful VT ablation. The present research investigates the post-ablation changes in SAECG after RFCA of VT and their relation to the procedural long-term outcomes. Methods Thirty-three patients (31 male; age 68 ± 9 years; EF 36 ± 12%) with ischemic VT were prospectively enrolled to receive RFCA. One VT (range 1–7) per patient was ablated using substrate-guided RFCA and complete success was achieved in 28 (85%) cases. SAECG was performed before (t1), immediately after (t2), and at least 6 months (t3) after the RFCA. Results After RFCA, the amount of patients showing abnormal SAECG decreased from 82% initially (t1) to 57.6% post-interventionally (t2); P = 0.008; and remained unchanged thereafter in 57% (t3). Patients who experienced VT recurrence (VT+) during the follow-up period had broader averaged QRS (t2): (VT+) 150 ± 26 vs. (VT−) 129 ± 21 ms; P = 0.015, as well as longer LAS40 (t2): (VT+) 60 ± 26 vs. (VT−) 43 ± 18 ms; P = 0.03. Abnormal SAECG (t2) was a strong predictor for VT recurrence: HR 5.4; 95% CI 1.5–21. SAECG detected more late potentials in patients with inferior than in those with anterior scars: 95% vs. 58%; P = 0.016. Conclusions RFCA of VT in the left ventricle can improve an abnormal SAECG in some patients after myocardial infarction. Normal SAECG after RFCA of VT is associated with a lower risk for VT recurrence and death.

Late potentials on signal-averaged electrocardiography eliminated by successful catheter ablation of premature ventricular contractions in a nonischemic cardiomyopathy patient

“… 2 Additionally, in recent years, it has been reported that an improvement in an abnormal SA-ECG after ventricular tachycardia (VT) ablation is associated with a lower risk of VT recurrence and mortality. 3 , 4 In these articles, the authors mentioned that substrate modification contributes to the elimination of the LPs. They also concluded that normalization of the SA-ECG could be an adjunctive marker to predict procedural success after ablation in ICM patients.…”

“…These facts may have led to the significant elimination of LPs after a successful ablation. Dinov and colleagues 4 suggested a significant correlation between the surface area of the endocardial scar and filtered QRS duration. Although this previous report was regarding ICM patients, a significant volume of fibrotic scar may lead to positive surface LPs even in NICM.…”