Incidence of Left Ventricular Systolic Dysfunction in Asymptomatic, Incidently Detected Left Bundle Branch Block (LBBB) in Apparently Healthy Individuals: A Prospective Observational Study at a Tertiary Care Cardiac Center in North India

Background: Left bundle branch block (LBBB) is often associated with significant heart disease and is often the result of myocardial injury, strain or hypertrophy, it can also be seen in patients without any particular clinical disease. The significance of LBBB has not been well studied in subjects without myocardial infarction or pre-existing heart failure. Therefore, we sought to study the incidence of LV systolic dysfunction in asymptomatic, incidentally detected LBBB in apparently healthy individuals. Aims and objectives: To study the incidence of LV systolic dysfunction in asymptomatic incidentally detected LBBB in apparently healthy individuals. Material and methods: A total of 150 patients were enrolled for study over a period of two years after written informed consent was obtained. All patients included in study attended hospital outpatient department for general and routine check-up and where completely asymptomatic. Patients with incidentally detected LBBB on 12 lead surface Electrocardiogram (ECG) were further evaluated by Echocardiography for LV systolic function. Results: The study observed LBBB is more common in males (61.3%) and is very rare below 40 years of age (0.053%). LBBB is common clinical entity after 60 years of age (40% in our group). Our study found asymptomatic LBBB patients have normal LV systolic function, paradoxical septal motion, normal ejection fraction (EF > 50%) in 54% of patients. Asymptomatic LBBB rarely has more than mild LV systolic dysfunction on echocardiography. We found only 2% of patients with EF < 40%). Conclusion: Asymptomatic LBBB is more common in males and is very rare below 40 years of age. Asymptomatic LBBB patients have near normal LV systolic function. Significant numbers of patients with asymptomatic LBBB have subclinical LV systolic dysfunction. Significant LV systolic dysfunction in LBBB is uncommon in asymptomatic patients.