Related Experiment Video
Updated: Jun 15, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Ventricular dyssynchrony patterns in left bundle branch block, with and without heart failure
Hygriv B Rao1, Raghu Krishnaswami, Sharada Kalavakolanu
1CARE Hospital, Institute of Medical Sciences, Hyderabad, India. hygriv@hotmail.com
Insights
Heart failure patients with LBBB often show dyssynchrony, impacting cardiac resynchronization therapy selection. Lateral wall delays are common in heart failure, unlike in normal LBBB hearts.
Area of Science:
- Cardiology
- Echocardiography
- Heart Failure Management
Background:
- Ventricular dyssynchrony assessment is crucial for cardiac resynchronization therapy (CRT) candidate selection.
- Regional dyssynchrony patterns in heart failure (HF) with left bundle branch block (LBBB) are not well-defined.
Purpose of the Study:
- To delineate regional dyssynchrony patterns in patients with LBBB, with and without heart failure.
Main Methods:
- Tissue Doppler Imaging (TDI) analyzed velocity curves from septal and lateral walls.
- Interventricular dyssynchrony (IVD) and left ventricular dyssynchrony (LVD) assessed by timing differences.
- A delay of ≥40 msec defined significant dyssynchrony.
Main Results:
- 72% of HF patients with LBBB exhibited dyssynchrony versus 16% in controls (P<0.01).
- Lateral wall dyssynchrony was prevalent in HF (37%) but absent in controls (P<0.01).
- Septal dyssynchrony was similar between groups (16%, P=NS).
Conclusions:
- Significant dyssynchrony is common in HF patients with LBBB, with heterogeneous regional distribution.
- Dyssynchrony can occur in LBBB without HF, but typically spares the lateral wall.
- Lateral wall delay may be a more specific indicator of dyssynchrony in HF patients.
Background:
Assessment of ventricular dyssynchrony in patients with heart failure is used for selecting candidates for cardiac resynchronization therapy (CRT). The patterns of regional distribution of dyssynchrony in a population with LBBB with and without heart failure have not been well delineated. This aspect forms the object of the study.
Methods:
Tissue Doppler Imaging (TDI) data of consecutive patients with heart failure and LBBB (Group A) was compared with those with LBBB and normal LV function (Group B). All patients had standard 2D-echocardigraphic examination and TDI. Tissue velocity curves obtained by placing sample volumes in opposing basal and mid segments of septal, lateral, inferior, anterior and posterior walls were analyzed. Inter ventricular dyssynchrony (IVD) was assessed by the difference between aortic and pulmonary pre ejection intervals. LV dyssynchrony (LVD) was assessed by the difference in times to peak velocity. A delay of >/= 40 msec was considered significant for presence of IVD and LVD.
Results:
There were 103 patients in Group A and 25 in Group B. The mean QRS duration and PR intervals respectively were 146 +/- 25 vs. 152+/-20 msec and 182+/- 47 vs. 165+/-36 msec. (p=NS) LVEF in the 2 groups were (32 +/- 6 % vs. 61+/- 11%; p< 0.01). Prevalence of dyssynchrony in the HF group compared to Group B was 72% vs. 16%, (P< 0.01). Lateral wall dyssynchrony in the 2 groups was 37% vs. 0% (p< 0.01) while septal dyssynchrony was 16% vs. 16% (p- NS).
Conclusions:
72% of heart failure patients with LBBB have documented dyssynchrony on TDI, which has a heterogeneous regional distribution. Dyssynchrony may be seen in LBBB and normal hearts but it is does not involve the lateral wall. Septal dyssynchrony in heart failure patients may not have the same significance as lateral wall delay.
Related Concept Videos
Dysrhythmias IV: Characteristics of Bradyarrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Cardiomyopathy II: Dilated Cardiomyopathy
Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias I: Introduction
Heart Failure II: Pathophysiology

