Blog

Left Bundle Branch Block (LBBB)

Left Bundle Branch Block


Left Bundle Branch Block (LBBB)

Overview:
This infographic explains the etiology, risk factors, diagnostic criteria, mimics, and management strategies for Left Bundle Branch Block (LBBB). LBBB is a significant electrocardiographic abnormality indicating conduction delay through the left bundle branch, often linked to structural heart disease.

Etiology:

  • Fibrosis and degeneration due to aging
  • Myocardial pathology
  • Compression of the left bundle branch

Risk Factors:

  • Coronary artery disease
  • Hypertension
  • Myocarditis
  • Cardiomyopathy
  • Valvular and congenital heart disease
  • Anterior myocardial infarction

Definition – AHA/ACC/HRS LBBB Criteria:

  1. QRS duration ≥120 ms
  2. Broad, slurred R wave in lateral leads (I, aVL, V5, V6)
  3. Absence of Q waves in leads I, V5, V6
  4. Prolonged R peak time in V5 and V6 >60 ms
  5. Initial small R wave in V1-V3
  6. Discordant ST/T waves opposite the QRS complex

Mimics:

  • Paced rhythm
  • Left ventricular hypertrophy (LVH)
  • Wolff-Parkinson-White (WPW) syndrome
  • Ventricular tachycardia (VT) originating from the right ventricular outflow tract

Management & Prognosis:

  • Asymptomatic LBBB: Monitor for structural heart disease.
  • LBBB with coronary artery disease (CAD): Associated with a higher risk of adverse cardiovascular outcomes.
  • CRT (Cardiac Resynchronization Therapy) is beneficial in patients with LBBB and reduced ejection fraction (EF ≤35%).
  • Close monitoring for progression to AV block is recommended, particularly in patients with TAVR or bundle branch reentrant ventricular tachycardia (BBRVT).

Produced by:

Edited by:

This comprehensive resource provides a deeper understanding of the diagnostic and therapeutic implications of LBBB, equipping healthcare providers to improve clinical outcomes.

CardioNerds Infographics

Explore our comprehensive collection of infographics, categorized by cardiovascular topics such as heart failure and transplantation, arrhythmias and electrophysiology, cardio-obstetrics, cardiovascular imaging, congenital heart disease, prevention, coronary artery disease, critical care, hypertension, pericardial disease, pulmonary hypertension, valvular heart disease, vascular disease, women’s cardiovascular health, diversity, inclusion, and more!

Feel free to download and share these visuals in presentations or on social media. Please use the infographics as provided—without altering or cropping out the creators’ credit.

For even more learning, explore the CardioNerds Tweetorial Page, featuring a curated collection of educational tweetorials!

You are currently viewing Left Bundle Branch Block (LBBB)