The role of catheter ablation for ventricular tachycardia in patients with ischemic heart disease

Catheter ablation for ventricular tachycardia in ischaemic heart disease; acute success and long-term outcome

OBJECTIVES

We conducted a study to assess the acute procedural success and the long-term effect of radiofrequency ablation (RFA) for ventricular tachycardia (VT) in patients with ischaemic heart disease.

DESIGN

We included 90 patients with ischaemic heart disease treated with RFA for VT in our institution. Data were obtained from patient files, and implantable cardioverter-defibrillator (ICD) discharges were recorded from in-house and remote follow-up data. Recurrence of VT during follow-up was noted as date of first ICD therapy for VT or first recurrence of symptomatic VT.

RESULTS

After the initial RFA procedure no VT was inducible in 42 patients (47%), non-clinical VT was inducible in 21 patients (23%), and the clinical VT was still inducible in 14 patients (16%). The procedural success was indefinable in 13 patients (14%). After a median follow-up of 33 months after the latest RFA, 38 patients (42%) stayed free from recurrent VT. The number of ICD shocks/year was significantly reduced from median 1.1 (interquartile range: 0.3-2.8) to 0 (0-0.4) (p < 0.0001).

CONCLUSIONS

Procedural success rate as well as long-term freedom from recurrent VT is modest after RFA for VT in ischaemic heart disease. However, ICD discharges are significantly reduced after RFA, and a considerable proportion of patients remain free from recurrent VT during the long-term follow-up.

Safety, long-term results, and predictors of recurrence after complete endocardial ventricular tachycardia substrate ablation in patients with previous myocardial infarction

Conduction channels and electrograms with isolated component/late potentials are sensitive markers of the substrate of post-myocardial infarction sustained monomorphic ventricular tachycardia (VT). Ablation of all conduction channels and isolated component/late potentials (complete endocardial VT substrate ablation [CEVTSA]) during sinus rhythm could simplify and facilitate the ablation procedure, mainly in patients without references for clinical VT substrate identification. The aim of this study was to assess the safety, efficacy, and predictors of VT recurrence after CEVTSA. Electroanatomic mapping and CEVTSA were performed in 59 post-myocardial infarction patients (mean age 67 ± 9 years, mean left ventricular ejection fraction 30 ± 11%), 24 of whom did not have clinical VT substrate references. The mean areas of scar (≤1.5 mV) and dense scar (≤0.5 mV) were 76 ± 42 and 34 ± 24 cm(2), respectively; isolated component/late potentials and conduction channels were identified and ablated in 97% and 83% of patients (mean ablation area 14 ± 10 cm(2)). No life-threatening complications occurred during the procedure. After 1 year and at the end of follow-up (mean 39 ± 21 months), 81% and 58% of patients were free of VT. No differences were observed between patients with and without specific clinical VT substrate identification. Univariate analysis identified the left ventricular ejection fraction, VT cycle length (VTCL), infarct location (inferior vs anterior), and dense scar area as predictors of VT recurrence, and Cox analysis identified VTCL (hazard ratio 0.42, p <0.001) and dense scar area (hazard ratio 2.65, p <0.0006) as independent predictors. No patients with dense scar area ≤25 cm(2) and VTCL >350 ms had recurrences. In conclusion, CEVTSA is safe and effective, even in patients without clinical VT substrate identification. Scar area and VTCL are valuable predictors of VT recurrence.