The Clinical and Angiographic Profile and Outcomes of Patients With Left Bundle Branch Block (LBBB): An Observational Study From a Tertiary Care Center in North India

TL;DR

This study examines the clinical features and outcomes of 200 patients with left bundle branch block in North India, finding that many have heart disease and that older patients with symptoms should undergo coronary angiography.

Contribution

The study provides insights into the clinical profile and outcomes of symptomatic LBBB patients in a North Indian population, emphasizing the role of coronary angiography in diagnosing obstructive CAD.

Findings

80% of patients had left ventricular systolic dysfunction, and 39% had obstructive coronary artery disease.

Older age, angina, diabetes, and reduced ejection fraction were significantly associated with obstructive CAD.

Six-month mortality was 6%, primarily in patients over 70 years old.

Abstract

Background and objective

Left bundle branch block (LBBB) is a common electrocardiographic abnormality resulting from impaired conduction in both the His-Purkinje system's anterior and posterior left fascicles. LBBB prevalence varies with age, gender, race, and underlying cardiovascular conditions. It affects 0.06-0.1% of the general population, rising to 6-7% in those over 80, and is often detected incidentally in older males. Although once considered a ST‐segment-elevation myocardial infarction (STEMI) equivalent in chest pain, recent data indicate a low risk of myocardial infarction. Diagnosing coronary artery disease (CAD) in these patients is challenging due to limitations of noninvasive tests, often necessitating coronary angiography (CAG) for confirmation. CT angiography is typically the first-line test for patients under 65, while stress nuclear imaging or dobutamine stress echo is preferred in those 65 and older. Certain ECG changes, like ST elevation or depression, may suggest myocardial infarction in LBBB cases. This study aimed to examine various demographic and clinical features, as well as outcomes, in patients presenting with symptomatic LBBB

Methods

This non-randomized, prospective, single-center observational study aimed to evaluate the clinical characteristics, demographic profile, and outcomes of patients presenting with symptomatic LBBB. All enrolled patients underwent CAG, with or without subsequent revascularization, as part of their diagnostic workup.

Results

A total of 200 symptomatic LBBB patients, comprising 104 males (52%), with a mean age of 60.2 ± 11.4 years, were included in the study. Hypertension and diabetes mellitus were the most common comorbidities, observed in 98 (49%) and 68 (34%) patients, respectively. Additionally, 160 (80%) patients exhibited some degree of left ventricular (LV) systolic dysfunction. CAG showed normal findings in 100 patients (50%), obstructive CAD in 78 (39%), and non-obstructive CAD in 22 (11%). The left anterior descending (LAD) artery was the most involved vessel, affected in 70 patients (70%). Among the 78 patients with obstructive CAD, 72 (92.3%) had severe obstruction. The LAD artery was the most affected vessel, observed in 60 patients (76.9%). Percutaneous coronary intervention (PCI) was performed in 42 patients, eight were referred for coronary artery bypass grafting (CABG), and 28 were managed with guideline-directed medical therapy (GDMT). Age ≥50 years (p=0.005), angina (p<0.001), diabetes mellitus (p<0.001), and LV ejection fraction (LVEF) ≤50% (p=0.006) were significantly associated with obstructive CAD. Mortality was also significantly higher in this group (p=0.001). During the six-month follow-up, 12 patients (6%), all over 70 years, died, resulting in an overall survival rate of 94% despite the high-risk profile.

Conclusions

Older patients with LBBB who present with angina, cardiovascular risk factors, and LV systolic dysfunction should be evaluated for CAD by using CAG, especially when troponin markers are elevated (troponin I >0.04 ng/mL).