الفهرس 
1- IntroductionOnly 14 pages are availabe for public view
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Abstract
Both ischemic cardiomyopathy (IDCM) and non-ischemic cardiomyopathy (NIDCM) are characterized by cardiac dilation and dysfunction. Differentiation between IDCM and NIDCM using non-invasive image modalities is a clinical dilemma. LBBB imparts additional challenges into the etiologic diagnosis of DCM. This study employed 2D strain imaging to characterize myocardial deformation and extent of mechanical dys-synchrony in IDCM and NIDCM and their possible application for precise diagnosis.
Methods: We examined myocardial longitudinal and circumferential strain at segmental and global levels and LV twist derived from basal and apical rotation in 36 DCM patients with LBBB. Of these patients, 16 were diagnosed with IDCM and 20 with NIDCM using coronary angiography, they were compared to 30 healthy controls. The study patients had LV diastolic diameter >55 mm and ejection fraction (EF) <45 %.
Results: NIDCM were younger in age (45.7±14 versus 61.5±7.5, P<.0001) had larger LV end systolic (P<.03), end diastolic (P<.02) dimensions, LAV (P<.003), more mitral regurgitation(P<.02) and lower EF (31% vs 39%, P<.04). Compared with IDCM, patients with NIDCM had lower longitudinal strain of septal, lateral, inferior walls and global longitudinal strain (GLS), P<.001 and lower LV twist (1.64±1.4º vs. 3.25±2.1º, p< 0.01). IDCM had prevalent typical contraction activation (38% versus 5%) and higher electromechanical delay compared with NIDCM (P<.01). However, there was no significant difference in circumferential strain between LBBB groups. Using ROC analysis value
Summary
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of GLS <3.4% could predict NIDCM with 87.5% sensitivity and 78.9% specificity, area under curve is 0.836 and p < 0.001.
Conclusion: In dilated cardiomyopathy with LBBB, deformation imaging is offering newer mechanistic insights and enables detailed characterization of ischemic and non ischemic etiologies in heart failure patients.