This study is investigating whether using ultrasound directly inside the heart during ablation of heart rhythm disorders in the ventricles can reduce radiation exposure for patients.

During an ablation, catheters are guided through the heart to treat the abnormal electrical signals. Usually, X-ray imaging (fluoroscopy) is used to see where the catheters are, which exposes both patients and hospital staff to radiation.

The study is randomized and controlled: half of the participants will have the ablation with ultrasound inside the heart, and the other half will have the standard ablation without ultrasound during the procedure. The main goal is to compare the amount of X-ray time used during the procedure. Secondary goals are to look at safety, effectiveness, and the total procedure time.

Patients with premature ventricular contractions or ventricular tachycardia can take part. A total of 70 people will be included, 35 in each group. Using ultrasound inside the heart makes it possible to see the catheters and heart structures directly, so many steps can be done without X-rays. This could make ablations safer and reduce radiation exposure.

The study is being carried out at Inselspital, Bern University Hospital, and at University Hospital Basel. All steps are standardized and data are collected carefully. The results will show whether ultrasound during ablations can significantly reduce radiation and make ablations more efficient and safer.

Inclusion Criteria:

• Patients (≥18y) undergoing a premature ventricular contraction or ventricular tachycardia ablation.

Exclusion Criteria:

• Origin of ventricular arrhythmia with high likelihood in the right ventricular outflow tract (left-bundle-inferior axis, >V4 transition precordially)
• Primary epicardial ablation planned
• Congenital heart disease
• Presence of a mechanical tricuspid valve prosthesis
• Unwilling or unable to comply fully with study procedures and followup