Improvement of abnormal systolic motion of the interventricular septum with cardiac resynchronization therapy
Belma Yaman1, Hatice S Kemal1, Yurdaer Dönmez2
1Department of Cardiology, Near East University Faculty of Medicine, Nicosia, Cyprus.
Insights
Cardiac resynchronization therapy (CRT) improves septal contraction in patients with left bundle branch block (LBBB). This therapy enhances left ventricular (LV) systolic function by correcting abnormal septal motion, improving overall cardiac performance.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- Left ventricular dyssynchrony mechanisms remain debated, with differing views on septal dyskinesia versus lateral wall motion abnormalities.
- Left bundle branch block (LBBB) significantly impacts left ventricular (LV) systolic function and synchrony.
Purpose of the Study:
- To evaluate abnormal systolic motion in individual myocardial segments using pulsed tissue Doppler imaging (TDI).
- To assess the improvement in LV systolic function following cardiac resynchronization therapy (CRT) in patients with LBBB.
Main Methods:
- Included 26 patients with LBBB, wide QRS duration (≥120 ms), and low ejection fraction (EF <35%) undergoing CRT.
- Utilized pulsed TDI from apical 4-chamber and parasternal short axis views (PSAX).
- Measured echocardiographic parameters with CRT both on and off.
Main Results:
- Systolic ejection time (ET) for anteroseptal and posterolateral walls was significantly longer with CRT on versus off (P < .001 and P = .015, respectively).
- Septal annulus systolic ET in the apical 4-chamber view showed significant improvement with CRT on (P = .014).
- Strong correlations were found between septal systolic ET (PSAX), aortic velocity time integral (VTI), QRS duration, and EF (r = .587, P = .002; r = .479, P = .013; r = .440, P = .025).
Conclusions:
- CRT improves circumferential contraction of septal myocardial fibers, correlating with increased aortic VTI and shortened QRS duration.
- Septal contraction deterioration is a key mechanism in LBBB patients.
- CRT may enhance myocardial contraction by correcting abnormal septal systolic motion.
Background:
There is no consensus in the literature regarding what is the responsible mechanism of left ventricular dyssynchrony; septal dyskinesia or late movement of left ventricle (LV) lateral wall. We aim to evaluate the abnormal systolic motion in each myocardial segment and the improvement of LV systolic function with pulsed tissue Doppler imaging (TDI) in patients undergoing cardiac resynchronization therapy (CRT) with left bundle branch block (LBBB).
Methods:
A total of 26 patients undergoing CRT implantation with LBBB, wide QRS duration (≥120 ms), and low ejection fraction (EF) (<35%) were included. Pulsed TDI was taken from apical 4-chamber view and parasternal short axis view (PSAX). All echocardiographic parameters were measured when CRT is on and off.
Results:
Systolic ejection time (ET) of anteroseptal and posterolateral wall of LV in PSAX was statistically significantly longer in CRT on group (321.6 ± 62.7 vs 237.5 ± 59.3 ms, P < .001; 323.9 ± 58.0 vs 289.4 ± 43.7 ms, P = .015, respectively). In apical 4-chamber view, septal annulus systolic ET is significantly longer in CRT on group than CRT off group (315.8 ± 57.2 vs 287.3 ± 42.2, P = .014). Also, there was a strong correlation between systolic ET of the septum in PSAX with aortic velocity time integral (VTI), QRS duration and EF (r = .587, P = .002; r = .479, P = .013; r = .440, P = .025; respectively).
Conclusion:
Circumferential contraction of septal myocardial fibers is improved with CRT and it is strongly correlated with increase of aortic VTI and shortening of QRS duration. These findings predict the deterioration of septal contraction as the main mechanism in patients with LBBB pattern and, CRT may improves myocardial contraction by correcting septal systolic motion.
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