Radiosurgery for the Treatment of Refractory Ventricular Extrasystoles and Tachycardias

Inclusion Criteria:

• Patients with structural heart disease and implantable cardioverter defibrillator (ICD)

• Age > 18 years

• either

1. Recurring symptomatic monomorphic ventricular tachycardia that requires ICDintervention (e.g. shock or anti-tachycardia stimulation). At least 3 episodeswithin the 3 months prior to inclusion or

2. induction of symptomatic monomorphic ventricular tachycardia that requires ICDintervention (e.g. shock or anti-tachycardia stimulation). Induction triggeredby ICD or during electrophysiology studies (EPS) or both, a) and b)

• Refractory to antiarrhythmic combination therapy

• Beside the cardiac conditions: No competing illness that would additionally limitthe life expectancy to less than 6 months

• No prior radiation therapy in the thorax area

• No pregnancy and no active breastfeeding

• Ability to consent and consent to study participation

Exclusion Criteria:

• ICD electrode malfunction of ICD readings outside reference range

• Lack of evidence of a myocardial scar (Computer tomography or magnetic resonancetomography for MRI-capable ICD aggregates or electrophysiological measurement)

• No possible induction of symptomatic monomorphic ventricular tachycardianon-persistent or persistent with delivery of ICD therapies such as antitachycardicpacing or shock

• Contraindication to radiosurgery (e.g. precise target volume definition not possibledue to image artifacts created from a left ventricular assist device (LVAD))

• Inability to consent or missing or withdrawn consent