Mechanical and Electrical Dyssynchrony During His-Bundle Pacing Versus His-Bundle Area Right Ventricular Pacing

Permanent His Bundle Pacing (HBP) is a well-known method of cardiac pacing which is increasingly used in everyday practice. After lead implantation in His Bundle area (HBA) capture of various tissues can be achieved: A. right ventricular myocardium near to HBP; B. cardiac conduction system selectively or nonselectively (with concomitant regional myocardium activation). The different excitability and refractory periods decide which tissue, myocardium or/and the conduction system is effectively paced. A lot of clinical trials revealed the advantage of HBP over apical ventricular pacing (AVP). HBP improves clinical (NYHA, quality of life, hospitalization rate) and echocardiographic (left ventricular dimension and ejection fraction) indicators of heart failure. We are going to compare mechanical and electrical synchrony during the various type of myocardium activation: HBP (nsHBP or sHBP), RV pacing near HBA and native heart rhythm (if possible) in each patient recruited to the study. Adequate pacemaker programming will allow achieving different activations as shown above. The mechanical synchrony will be estimated by transthoracic echocardiography and the electrical one by the detailed analysis of ECG.