At least as early as 1989 CL Grines described significant functional abnormalities in patients with left bundle branch block (LBBB).
Blanc et al in 2005 and again Vaillant et al in 2013 described patients with LBBB induced heart failure (HR) that was impressively improved by cardiac resynchronization therapy (CRT) in the form of bi ventricular pacing.Blanc commented that this was a new concept of left ventricular dyssynchrony - induced cardiomyopathy.
In spite of the fact that it has been known for 30 years that left ventricular functional changes are caused by LBBB and it has been fifteen years since a LBBB induced cardiomyopathy was described we continue to find current journal articles that depict BBB without other cardiac disease as not a clinical problem.
R Singh et al (1) recently reported the results of His Bundle Pacing on 9 patients with LBBB-mediated cardiomyopathy. The left ventricular ejection fraction increased on average from 25% to 50% while the left ventricular end-diastolic volume decreased from 55 to 48mm., while the QRS duration decreased from 152 to 115 milliseconds. This represents another article indicating that His pacing gives results as good or perhaps better than Bi ventricular pacing for CRT.
1) Singh, R et al His-Bundle pacing: A novel treatment for left bundle branch-mediated cardiomyopathy.
J of Cardiovascular electrophysiology 2020 vol 31 no 10.