1. Nonischemic regional wall motion abnormality - LBBB
Dr sajeer K T
Senior Resident,
Dept. of Cardiology,
Medical College, Calicut

2. Normal spread of electrical activity in the heart
Depolarization of the ventricular muscle starts at the left side of the interventricular septum and moves first to the right across the midportion of the septum

3. Normally conduction down the left bundle precedes that down the right bundle by 10 to 20 ms
Normal initial activation of the heart is in the proximal mid septum on the left ventricular side

4. LBBB Initial septal activation is reversed.
Right side of the ventricular septum is initially activated
Right septal activation before activation of the body of the left ventricle
Initial right to left movement of the ventricular septum (anterior to posterior)

5. Interrelation between right and left ventricular events in normal subjects and LBBB

6. Normal M-mode Echo

7. Interventricular septal motion in LBBB and the relation to dynamic interventricular asynchrony.
Circulation Vol 79, No 4, April 1989

8. High amplitude oscillations of the IVS
LV –RV Asynchrony
- Contraction
- Ejection
- End systole
- End diastole
Abnormal interventricular septal oscillations

9. M-mode echocardiogram recorded in a patient with a left bundle branch block shows an early systolic downward motion of the ventricular septum (arrows).

10. LBBB v/s Ejection fraction
Regional ejection fractions of apical and lateral segments similar in normal (NL) and left bundle branch block (LBBB) groups.
Septal ejection fraction decreased in LBBB patients (40+16%) compared with normal subjects (67±+7%).
Circulation Vol 79, No 4, April 1989

11. Mechanism for global cardiac abnormalities in isolated left bundle branch block
Altered Ventricular Activation
Delayed LV Contraction
Decreased LV diastolic time
LV-RV Asynchrony
Abnormal septal Motion
Abnormal LV Septal EF

12. Nonischemic Regional Wall Motion Abnormality

13. Thank you