Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT)

Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT)

Cardiac resynchronization therapy (CRT) is usually done by biventricular pacing with a right ventricular lead and a left ventricular lead in a coronary vein. This often results in relatively broader QRS complex and suboptimal response. A new approach is to use left bundle branch area pacing in lieu of the usual right ventricular lead and coronary venous left ventricular pacing. This novel approach has been called left bundle branch–optimized cardiac resynchronization therapy (LOT-CRT) [1].

International LBBAP collaborative study group assessed the feasibility of LBBAP-optimized CRT in non consecutive patients with CRT indications. Addition of the left bundle branch area or coronary venous lead was at the discretion of the implanting physician, who was guided by suboptimal paced QRS complex, and/or on clinical grounds. LOT-CRT was successful in 91 of 112 patients attempted, with 81% success.

At baseline, left bundle branch block was present in 47 patients, non specific intraventricular conduction delay in 25, right ventricular pacing in 26 and right bundle branch block in 14. Mean left ventricular ejection fraction was 28.7%. Mean fluoroscopy time was 27.3 minutes. QRS complex was significantly narrower with LOT-CRT. Left ventricular ejection fraction improved to a mean of 37% at follow up after 3 months and there was decrease in left ventricular end diastolic diameter and NT-proBNP levels. NYHA functional class also improved.

Another related procedure is His-optimized cardiac resynchronization therapy (HOT-CRT). In a study, 19 patients with standard indication for CRT, His-optimized cardiac resynchronization therapy was tested. It was found to improve ventricular electrical synchrony beyond biventricular pacing and multipoint pacing [2].

References

1. Jastrzębski M, Moskal P, Huybrechts W, Curila K, Sreekumar P, Rademakers LM, Ponnusamy SS, Herweg B, Sharma PS, Bednarek A, Rajzer M, Vijayaraman P. Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group. Heart Rhythm. 2022 Jan;19(1):13-21. doi: 10.1016/j.hrthm.2021.07.057. Epub 2021 Jul 30. PMID: 34339851.
2. Zweerink A, Zubarev S, Bakelants E, Potyagaylo D, Stettler C, Chmelevsky M, Lozeron ED, Hachulla AL, Vallée JP, Burri H. His-Optimized Cardiac Resynchronization Therapy With Ventricular Fusion Pacing for Electrical Resynchronization in Heart Failure. JACC Clin Electrophysiol. 2021 Jul;7(7):881-892. doi: 10.1016/j.jacep.2020.11.029. Epub 2021 Feb 24. PMID: 33640346.