ECG Tip: LBBB vs. RBBB Made Easy! 🫀 👉 But what are these blocks? A bundle branch block happens when the electrical signals traveling through the heart’s bundle branches (which control the ventricles) are slowed or blocked. This delay can affect how the ventricles contract, leading to the characteristic wide QRS complexes seen on an ECG. Causes can include structural heart changes, ischemia, hypertension, or scarring from prior heart conditions. 👉 Want to learn more? Watch our latest YouTube v