Electromechanical Profiling in Genotyped Dilated Cardiomyopathy with Left Bundle Branch Block

Area of Science:

• Cardiology
• Genetics
• Electrophysiology

Background:

• Dilated cardiomyopathy (DCM) management often includes genetic testing.
• Left bundle branch block (LBBB) in DCM patients presents unique diagnostic and therapeutic challenges.
• The interplay between genetic variants, LBBB characteristics, and treatment response in DCM is not fully understood.

Purpose of the Study:

• To investigate the prevalence and impact of pathogenic/likely pathogenic (P/LP) variants in DCM patients with LBBB.
• To analyze the electromechanical profile of genotyped DCM patients with LBBB.
• To determine the relationship between genetic status, electromechanical parameters, cardiac resynchronization therapy (CRT) response, and clinical outcomes.

Main Methods:

• A multicenter cohort of 347 DCM patients with LBBB undergoing genetic testing was analyzed.
• Comprehensive electro- and echocardiographic phenotyping, including speckle-tracking strain analysis, was performed.
• CRT response was assessed by changes in end-systolic volume (ESV) and left ventricular ejection fraction (LVEF).

Main Results:

• Only 6% of DCM patients with LBBB carried P/LP variants.
• Genotype-positive patients displayed atypical LBBB features and reduced mechanical dyssynchrony.
• These patients showed poorer CRT response and worse clinical outcomes (mortality, heart failure hospitalization).

Conclusions:

• Genetic testing has limited diagnostic utility in DCM patients with LBBB.
• A distinct electromechanical profile in genotype-positive DCM with LBBB is associated with suboptimal CRT response and adverse prognosis.
• Combined genetic and electromechanical phenotyping may enhance risk stratification and personalized treatment strategies.