Abstract
Introduction: To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony. Methods: This was retrospective prospective study. Fifteen patients each with right ventricular (RV) apical (RV apex and apical septum) and non-apical (mid septal and low right ventricular outflow tract [RVOT]) were programmed to obtain 100% ventricular pacing for evaluation by echo. Location and orientation of lead tip was noted and archived by fluoroscopy. Electrocardiography (ECG) was archived and 2D echo radial dyssynchrony was calculated. Results: The baseline data was similar between two groups. Intraventricular dyssynchrony was significantly more in apical location as compared to non-apical location (radial dyssynchrony: 108.2 ± 50.2 vs. 50.5 ± 24, P < 0.001; septal to posterior wall delay [SLWD] 63.5 ± 27.5 vs. 34 ± 10.7, P < 0.001, SPWD 112.5 ± 58.1 vs. 62.7 ± 12.1, P = 0.003). The left ventricular ejection fraction was decreased more in apical location than non apical location. Interventricular dyssynchrony was more in apical group but was not statistically significant. The QRS duration, QTc and lead thresholds were higher in apical group but not statistically significant. Conclusion: Pacing in non apical location (RV mid septum or low RVOT) is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term.
Highlights
To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony
We planned this study to answer some of these questions by identifying the lead position on fluoroscopy and comparing electrocardiography (ECG) and dyssynchrony parameters with ventricular function on medium term follow up. 2-dimensional (2D) strain based speckle tracking which evaluates circumferential strain (CS), longitudinal strain (LS), and radial strain (RS) by self tracking of myocardial segments allows better advantage in comparison to tissue Doppler imaging as it does not depend on Doppler angle and monitors strains in two dimension rather than one dimension, increasing reproducibility and accuracy
Five patients in apical group had pacing lead in right ventricular (RV) apex position and 10 patients had in apical septal position; whereas in non apical group 7 patients had pacing lead in mid septum and 8 patients at low right ventricular outflow tract (RVOT) pacing (Table 1)
Summary
To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony. Conclusion: Pacing in non apical location (RV mid septum or low RVOT) is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term. 2-dimensional (2D) strain based speckle tracking which evaluates circumferential strain (CS), longitudinal strain (LS), and radial strain (RS) by self tracking of myocardial segments allows better advantage in comparison to tissue Doppler imaging as it does not depend on Doppler angle and monitors strains in two dimension rather than one dimension, increasing reproducibility and accuracy. We used this technique in our study
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