Purpose: Single site ventricular pacing can result in electromechanical dyssynchrony and LV dysfunction. A classic pattern by strain echocardiography pattern analysis has been defined that specifically identifies electromechanical dyssynchrony that leads to LV dysfunction in other populations. Our purpose is to evaluate for the presence of the classic pattern and an association with LV dysfunction in asymptomatic young subjects with chronic pacing.
Methods: Inclusion criteria of non-surgical 2nd or 3rd degree AV block, normal cardiac anatomy, chronic ventricular pacing (> 95% of beats) and a quality 4-chamber apical image were met by 24 retrospective and 10 prospectively enrolled subjects. Global longitudinal peak strain (GLS), the classic pattern of dyssynchrony, and time to peak strain were analyzed with Tomtec 2D strain software. Statistics included Spearman’s rank sum and Fisher’s exact test.
Results: Median age at study echo was 18.4 years (9.8, 22.5 years); all had prolonged QRS duration with paced BBB pattern. The classic pattern was seen in 38% (13/34) and was associated with a lower LVEF (37.5 vs 48.9%, p=0.001) and worse GLS (-10.7 vs -14.8%, p=0.03). Pacing site was not associated with the classic pattern (p=0.7). Only in subjects with the classic pattern was pacing duration associated with progressive LV dysfunction.
Conclusion: LV dysfunction was common in this asymptomatic population suggesting routine echocardiographic surveillance is important. The classic pattern of electromechanical dyssynchrony was commonly identified in this ventricular paced population and was associated with more significant LV dysfunction. Larger future studies with prospective, serial echocardiograms are necessary to confirm these findings.
Biomedical Journal of Scientific & Technical Research
Electromechanical Delay; Strain; Cardiac Pacing, LV: Left Ventricular
Daniel Forsha, David G Gamboa, Niels Risum, P Andrea Kropf, Christoph P Hornik, et al. Electromechanical Dyssynchrony and Clinically Silent Ventricular Dysfunction in Young Subjects with Ventricular Pacing for Congenital and Early Acquired Av Block. Biomed J Sci & Tech Res 20(2)-2019. BJSTR. MS.ID.003435.