Inclusion Criteria:  Age, 18-75 years Sinus node dysfunction/disease fulfilling criteria for elective pacemaker implantation according to current ESC guidelines (I, IIa, and IIb ) Optimization of chronic disease treatment Ability to provide informed consent to participate in the study Ability to understand patient information.  Exclusion Criteria:  Contraindications to invasive and noninvasive procedures used in the study Uncontrolled endocrine and systemic disorders Persistent atrial fibrillation Dilated cardiomyopathy Severe congenital heart valve disease or cardiomyopathy Functional NYHA class III/IV Left ventricular ejection fraction <35% Left atrial diameter >50 mm Previous catheter ablation Contraindications to anticoagulant treatment Contraindications to catheter ablation Chronic, advanced two- or third-degree atrioventricular block associated with structural heart disease Contraindications to noninvasive tests Pregnancy and lactation Previous cardiac surgery Implanted pacemaker device Neck and chest abnormalities Myocardial infarction in the previous 6 months Percutaneous coronary intervention in the previous 3 months Estimated survival <24 months Participation in another drug or medical device program Limited capacity to understand the study protocol or psychological disorders precluding informed consent to participate in the study. Any other uncontrolled chronic diseases, neck and chest abnormalities, or disorders that constitute a contraindication to catheter ablation, antiarrhytmic treatment, general anesthesia, or extracardiac vagal nerve stimulation (ECANS) Severe obesity (body mass index ≥40 kg/m2 )