Rationale: Nowadays ventricular tachycardia (VT) ablation in structural heart disease is performed primarily by early referral; while at the same time we still struggle with the limited longterm ablation success of endocardial VT ablation. An underestimated number of VTs from ischemic substrate have an epicardial exit. However, one cannot accurately predict who is in need of epicardial ablation. The investigators hypothesise endo/epicardial substrate homogenization in a first approach to be superior to endocardial substrate homogenization alone, in terms of recurrence on follow-up.

Objective: To show superiority of a combined endo/epicardial approach compared to a stepwise approach in the ablation of ventricular tachycardia in a population with ischemic cardiomyopathy on VT recurrence.

Study design: Multicenter prospective open randomized controlled trial. Study population: All patients above 18 years with an ischemic cardiomyopathy being referred for a ventricular tachycardia ablation.

Intervention: One group undergoes endo/epicardial ablation and the other group has endocardial ablation only as a first approach.

Main study parameters/endpoints: The main study endpoint is the difference in recurrences of ventricular tachycardia on follow-up - clinical or on implantable cardioverter defibrillator (ICD) interrogation - between the two ablation groups; secondary endpoints are procedure success and safety.

Inclusion Criteria:

1. clinical indication for ablation of a monomorphic ventricular tachycardia referred to one of the participating ablation centers
2. history of ischemic heart disease
3. ICD carrier or ICD implantation planned after the ablation
4. informed written consent

Exclusion Criteria:

1. current unstable angina as defined by current european guidelines
2. AMI < 30 days or in case of incessant VT < 14 days
3. absence of visualisation of the coronary anatomy (coronary angiogram /CT-angiogram)
4. significant coronary stenosis approachable and clinically relevant for intervention
5. presence of a mobile left ventricle thrombus seen on (contrast) echocardiography or MRI
6. previous pericarditis
7. presence of mitral/aortic mechanical valves prosthesis; previous coronary artery bypass graft; any other thoracic surgery that could cause pericardial adhesions
8. previous thoracic radiation therapy
9. contra-indication for general anaesthesia
10. age below 18 years