Continuation of Antiarrhythmics Following Ventricular Tachycardia Catheter Ablation

The investigators aim to study if patients that undergo catheter ablation for ventricular tachycardia benefit from continuation of Vaughan-Williams class III antiarrhythmic drugs for 3 months after their ablation.

Catheter ablation is a valuable option to control recurrent Ventricular Tachycardia (VT) in patients with structural heart disease. A recent trial proved that catheter ablation is superior to escalation of anti arrhythmic drugs (AADs) in prevention of VT recurrence and death (Sapp et al. N Engl J Med 2016; 375:111-121). However, even with ablation, approximately 20-50% of patients will have an episode of VT within one year. This is probably explained in part by the substrate (myocardial scar from cardiomyopathy) persists after VT ablation and that ablation lesions heal and evolve over days, weeks and even months. Most patients (if not all) of patients who undergo ablation are on AADs and usually have failed at least one of them. Furthermore, most AADs, and Vaughan Williams class III AADs in particular (the most frequently used to treat VT) carry significant and life-threatening side effects from pulmonary, hepatic and hematologic toxicities up to significant ventricular arrhythmias and death. Since these patients have already failed AADs, and the significant adverse profile of AADs, there is no evidence that the benefits of continuation of these drugs will surpass the risks after ablation. Therefore the investigators decided to ask the question:

Among patients with structural heart disease who undergo VT ablation, does continuation of class III AADs for 3 months, increases VT-free survival compared to discontinuation of antiarrhythmic drug therapy?

Based on expert consensus about clinical equipoise in regards of AAD continuation after VT ablation, the investigators decided to select patients with lowest risk of VT recurrence after ablation as our study population. The investigators aim to include in our study only those patients who have an Implantable Cardioverter-Defibrillator (ICD), who have NO inducible VT at the end of the ablation procedure and also who have NO inducible VT prior to discharge on a procedure called non-invasive programmed stimulation (NIPS). It has been shown that patients with inducible VT at the end of ablation and during NIPS have significantly higher risk of VT recurrence compared to those in whom VT was not induced. In NIPS, one uses the previously Implanted ICD to pace the ventricle fast enough to try to induce VT. Both procedures will be performed as usual practice in patients who undergo VT ablation in the arrhythmia service.

The specific aim of this pilot study is to evaluate whether the strategy of continuation of class III AADs following initial catheter ablation for VT, improves VT-free survival and reduces readmissions.

Eligibility Criteria:
Inclusion Criteria:

1. Age \>18 years.
2. Able to give written, informed consent
3. Structural heart disease.
4. Implanted and normally functioning ICD or undergoing ICD implant at index admission.
5. Undergoing initial radiofrequency ablation procedure for sustained monomorphic VT.
6. Receiving a class III AADs prior to VT ablation.
7. No VT inducible at the end of VT ablation.
8. No VT inducible on non-invasive programmed stimulation following VT ablation.

Exclusion Criteria:

1. LV assist device in place
2. Decompensated heart failure and/or requiring continuous inotropic therapy and/or awaiting cardiac transplantation
3. Ongoing acute coronary syndrome.
4. Mechanical prosthetic aortic and mitral valves.
5. Pedunculated or mobile left ventricular thrombus.
6. Persistent VT at the end of index catheter ablation.
7. Absolute contraindications for class III AADs.
8. Participation in other trial.
9. VT induced on NIPS after VT ablation.
10. Another reason for continuation of class III AADs (i.e., atrial fibrillation).