How to rebuild a damaged heart: The role of left bundle branch pacing to reduce functional mitral regurgitation

Left bundle branch pacing (LBBP) is in vogue since its first description in 2017. 1 Huang W. Su L. Wu S. et al. A novel pacing strategy with low and stable output: pacing the left bundle branch immediately beyond the conduction block. Can J Cardiol. 2017; 33 (e1–1736.e3): 1736 Google Scholar Searching the term left bundle branch pacing on PubMed yields 88 results in 2017, 135 in 2019, and 243 in 2021, indicative of the increasing academic interest in this form of conduction system pacing (CSP).Click or tap here to enter text. Cardiac resynchronization therapy (CRT) overcomes left ventricular electrical delay and associated dyssynchrony. A possible alternative to traditional CRT devices is CSP. His bundle pacing (HBP) can achieve CRT through recruitment of His-Purkinje fibers dedicated to the left bundle branch (LBB) to overcome LBB delay or block. 2 Deshmukh P. Casavant D.A. Romanyshyn M. Anderson K. Permanent, direct His-bundle pacing: a novel approach to cardiac pacing in patients with normal His-Purkinje activation. Circulation. 2000; 101: 869-877 Google Scholar The His Bundle Pacing Versus Coronary Sinus Pacing for Cardiac Resynchronization Therapy trial demonstrated HBP as a reasonable and possibly equivalent alternative to traditional CRT. 3 Upadhyay G.A. Vijayaraman P. Nayak H.M. et al. His corrective pacing or biventricular pacing for cardiac resynchronization in heart failure. J Am Coll Cardiol. 2019; 74: 157-159 Google Scholar HBP has reached some limitations in clinical practice with high pacing outputs to achieve HB capture, leading to diminished generator life span, implantation difficulties with frequent oversensing, and lead instability with a higher rate of dislodgment. 4 Keene D. Arnold A.D. Jastrzębski M. et al. His bundle pacing, learning curve, procedure characteristics, safety, and feasibility: insights from a large international observational study. J Cardiovasc Electrophysiol. 2019; 30: 1984-1993 Google Scholar LBBP bypasses His bundle recruitment and targets the slightly more distal LBB, thresholds tend to be lower, and lead stability improved in comparison to HBP. Both HBP and LBBP have been increasingly studied in recent years as alternatives to traditional CRT. In observational studies, LBBP is feasible, decreases heart failure (HF) symptoms, and improves echocardiography parameters in patients with cardiomyopathy with LBBB or need for CRT. 5 Vijayaraman P. Subzposh F.A. Naperkowski A. et al. Prospective evaluation of feasibility and electrophysiologic and echocardiographic characteristics of left bundle branch area pacing. Heart Rhythm. 2019; 16: 1774-1782 Google Scholar , 6 Vijayaraman P. Ponnusamy S. Cano Ó. et al. Left bundle branch area pacing for cardiac resynchronization therapy: results from the international LBBAP collaborative study group. JACC Clin Electrophysiol. 2021; 7: 135-147 Google Scholar , 7 Huang W. Wu S. Vijayaraman P. et al. Cardiac resynchronization therapy in patients with nonischemic cardiomyopathy using left bundle branch pacing. JACC Clin Electrophysiol. 2020; 6: 849-858 Google Scholar Response of functional mitral regurgitation in nonischemic cardiomyopathy to left bundle branch pacingHeart RhythmVol. 19Issue 5PreviewFunctional mitral regurgitation (FMR) in patients with cardiomyopathy is correlated with morbidity and mortality in heart failure. The response of FMR to cardiac resynchronization therapy (CRT) varies. Full-Text PDF