The usefulness of echo-based hemodynamic parameters in cardiac resynchronization therapy with conduction system pacing for optimal device programing

Background: His bundle pacing (HBP) has proved to be a valuable alternative enabling the physiological activation of cardiac contraction in cardiac resynchronization therapy (CRT). At present, however, little is known about the optimal method of programming of the His bundle-paced CRT systems in terms of achieving the best cardiac output. Aim: The aim of this study was to evaluate the impact of cardiac resynchronization therapy with conduction system pacing (CRT+CSP) on echo-based hemodynamic parameters in the early post-operative measurements. Methods: The study enrollment criteria included: permanent atrial fibrillation, heart failure and bundle branch block. All patients underwent implantation of CRT + HBP. During the post-operative phase, we aimed to optimize HOT-CRT settings in order to achieve the greatest cardiac output assessed by complex echocardiographic measurements. Results: The study included 21 patients, mean age 71.2 (6.3) years, predominantly men (71.4%) with non-ischemic cardiomyopathy 62%. All patients had heart failure with NYHA functional class III and IV (81%). Mean left ventricular ejection fraction was 27.5 (9.7%). The mean duration of the QRS complex was 148.8 ms. The effects of resynchronization pacing: HBP alone, HBP with left ventricular pacing, HBP with biventricular pacing (BiV) and BiV without HBP ​​were analyzed consecutively. HBP combined with left ventricular pacing demonstrated the best hemodynamic response. Conclusion: His bundle pacing coupled with LV pacing proved to be the most advantageous pacing program setting with regard to cardiac output. Moreover, it performed better than biventricular pacing and significantly better than RV pacing.