The main goal of the project is to prove that ultra-high-frequency ECG (UHF-ECG) can be used as a diagnostic tool that allows the prediction of patients susceptible to the negative effect of right ventricular myocardial pacing. The prediction will be based on the assessment of electrical dyssynchrony and local depolarization durations of left ventricular depolarization emerging during right ventricular pacing. If proved to be valid in left ventricular negative remodeling prediction, UHF-ECG-derived parameters of ventricular dyssynchrony could be used as markers allowing a lead placement optimization during an implant procedure. This information can help the operator to identify patients with the urgent need for physiological pacing (HB or LBBp) and patients in which a right ventricular myocardial pacing is sufficient and will not lead to the development of the negative left ventricular remodeling.

Inclusion Criteria:

1. expectation of permanent right ventricular pacing with atrio-ventricular delay set to 150/180 ms (130/160 resp.) for sensed/paced atrial events during a follow-up,
2. a good quality of images during echocardiography,
3. willingness to attend clinical check-ups in the implanting center for at least two years.
4. life expectancy of at least 2 years

Exclusion Criteria:

1. planned cardiac surgery or transcatheter aortic valve implantation
2. hypertrophic cardiomyopathy
3. an indication for implantable cardioverter-defibrillator, biventricular implantable cardioverter-defibrillator, or biventricular pacemaker
4. active myocarditis
5. cardiac surgery or coronary revascularization in the last ten days
6. persistent/permanent atrial fibrillation during randomization
7. severe aortic stenosis
8. mitral valvular disease with an indication to intervention.

360 patients with an indication for permanent pacing due to permanent conduction disease of/below the AV node