When patients visit the Kahn Center for Cardiac Longevity, we make sure they either have had a recent electrocardiogram (ECG) or we perform one no charge. One reason we do this is that about 1% of asymptomatic people demonstrate and abnormal ECG called a Left Bundle Branch Block (LBBB).
A lLBBB is a cardiac conduction disorder where the electrical signal that controls the heartbeat is delayed or blocked in the left bundle branch, which is part of the heart’s electrical system that sends impulses to the left ventricle. This causes the left ventricle to contract later than the right ventricle, leading to uncoordinated heart contractions and potentially less efficient blood pumping.
LBBB often occurs due to underlying heart conditions like coronary artery disease, heart attack, high blood pressure, cardiomyopathy, or valvular heart disease. It is more common in older adults or those with serious heart disease, but can sometimes appear without known heart problems.
Many people with LBBB have no symptoms, but it can cause dizziness, fainting, fatigue, shortness of breath, and worsen symptoms in heart failure patients.
Diagnosis is typically by electrocardiogram (ECG) showing characteristic changes, sometimes confirmed by echocardiography or other cardiac imaging.
A new study looked at the importance of a LBBB in predicting a serious disorder called Congestive Heart Failure (CHF).
STUDY
This longitudinal cohort study used data from 4 US sites participating in the Cardiovascular Health Study (1989-1990), collected from 1989 to 2013. Adults aged 65 years and older with a normal left ventricular ejection fraction (LVEF) and no history of CHF at baseline were included. Data were analyzed from February 2018 to October 2024.
The presence of LBBB as confirmed by 12-lead electrocardiograms was obtained on all participants at baseline.
RESULTS
Among 4541 individuals (age, 73 years; 2697 female [59%]), 44 (1.0%) exhibited LBBB at baseline, and 1321 (29%) received a diagnosis of CHF over a follow-up of 15years.
In the adjusted model, those with baseline LBBB had a times higher risk of incident CHF and a 5X greater odds of 5-year LVEF decline.
Suprisingly, there was no statistically significant increased risk of death observed but there was a trend towards more deaths in the LBBB group.
CONCLUSIONS
In this cohort study of individuals with structurally normal hearts, the 1% of patients with a LBBB were associated with an increased risk of CHF and a decrease in LVEF, suggesting that LBBB could be a potential target for early interventions to prevent deterioration of cardiac function and, ultimately, progression to CHF.
We will continue to perform ECGs in all patients at the Kahn Center even though insurance does not routinely reimuburse for them in a primary care office. If we find a LBBB, we perform comprehensive lab testing and schedule an echocardiogram to assess the LVEF, valves, and heart size. Optimal control of blood pressure, diet, fitness, sleep, and stress is emphasized. Some supportive supplements like coQ10 are routinely used to support heart health. Very few patients progress on to needing a pacemaker, usually for near or actual blackout episodes called syncope.
