This randomized study compares the effects of conventional (right ventricular pacing in patients with LVEF ≥ 40% and cardiac resynchronization therapy in patients with LVEF < 40 %) versus left bundle branch pacing on left ventricular remodelling in patients with reduced left ventricular ejection fraction (< 50 %) that need permanent pacemaker implantation after transcatheter aortic valve implantation (TAVI).

Bradycardic heart rhythm disturbances are a common complication of TAVI. Patients who will develop the indication for permanent pacemaker implantation after TAVI will be randomly assigned to either the experimental (left bundle branch pacing) or conventional (right ventricular pacing in patients with LVEF ≥ 40% and cardiac resynchronization therapy in patients with LVEF < 40 %) group. The investigators will compare the left ventricular ejection fraction (primary outcome) 12 months after randomization. The investigators will also compare electrocardiographic (QRS duration), clinical (NYHA status, 6-minute walking test, handgrip test, Kansas City Cardiomyopathy Questionnaire) and laboratory (proBNP) parameters 6 and 12 months, and other echocardiographic (left ventricular systolic and diastolic diameter, signs of dyssynchrony, myocardial work) parameters 12 months after pacemaker implantation in both groups.

Inclusion Criteria:

• Indication for permanent pacemaker implantation after transcatheter aortic valve implantation (during the same hospitalization)
• Left ventricular ejection fraction < 50 %.

Exclusion Criteria:

• Unsuccessful TAVI procedure with life expectancy < 1 year
• Ischemic cardiomyopathy with interventricular septal fibrosis (at least echocardiographic signs of fibrosis)
• Severe kidney failure (glomerular filtration rate < 30 ml/min)
• Previous permanent pacemaker