The Association Between Newly Acquired Permanent Left Bundle Branch Block Following Transcatheter Aortic Valve Replacement and New‐Onset Cardiomyopathy

BACKGROUND: Left bundle branch block (LBBB) frequently occurs after transcatheter aortic valve replacement (TAVR) and may lead to adverse clinical outcomes. OBJECTIVES: This study assesses the incidence of new-onset cardiomyopathy in patients with normal left ventricular systolic function who develop permanent LBBB post-TAVR. METHODS: We performed a retrospective analysis of consecutive TAVR patients at the University of Michigan Health System from January 2012 to June 2017. Exclusions included patients with pre-existing cardiac implantable devices, LBBB, right bundle branch block (RBBB), left ventricular ejection fraction (LVEF) < 50%, those requiring new permanent pacemakers, or with less than 1 year of follow-up. The primary outcome was new-onset cardiomyopathy (LVEF < 45% at 1 year), with secondary outcomes including all-cause mortality and changes in LVEF. RESULTS: A total of 273 patients were included (mean age 76.5 years; 47.6% female). Of these, 69 (25.3%) developed new-onset permanent LBBB. At 1 year, 27.5% of the LBBB group developed cardiomyopathy, compared to 2.0% in the control group (p < 0.01). The LVEF was significantly lower in the LBBB group (55.7% vs. 65.3%, p < 0.01). The composite endpoint of new-onset cardiomyopathy and mortality was higher in the LBBB group (39.1% vs. 10.3%, p < 0.01). CONCLUSION: Newly acquired permanent LBBB post-TAVR is associated with a significantly higher incidence of new-onset cardiomyopathy in patients with normal baseline LVEF.