Reduced Myocardial Strain Parameters in Subjects With Pectus Excavatum: Impaired Myocardial Function or Methodological Limitations Due to Chest Deformity?

Abstract

Pectus excavatum (PE) may cause symptoms and alter cardiopulmonary function. Left ventricular (LV) and right ventricular (RV) function have been reported to be impaired in PE subjects. However, this issue has not been systematically investigated with respect to the degree of chest wall abnormality. We aimed to evaluate the influence of severity of chest shape abnormality on myocardial strain parameters in PE subjects. We studied 30 healthy subjects (55.8 ± 14.0 year/old, 18 males) with PE, assessed by the ratio of chest transverse diameter over the distance between sternum and spine (modified Haller index, MHI, >2.5), and 30 controls (MHI ≤2.5) matched by age, sex, and cardiovascular risk factors. Participants underwent 2-dimensional (2D) transthoracic echocardiography implemented with 2D-speckle tracking echocardiography. Right-heart and left-heart chamber dimensions, and stroke volume, were significantly reduced in PE subjects (all P< 0.0001). While LV ejection fraction, E/A, and E/e', did not significantly differ between the 2 groups, all LV and RV strain and strain rate parameters were severely reduced in subjects with PE (P < 0.0001). Importantly, in PE subjects, but not in controls, LV global longitudinal strain, LV global circumferential strain, LV global radial strain, and RV free wall systolic strain, were all linearly correlated to MHI (all P < 0.0001). In healthy subjects with PE, abnormal chest anatomy progressively impairs myocardial strain. However, this impairment is not due to subclinical myocardial dysfunction; it might reflect intraventricular dyssynchrony due to compressive phenomena, or technical limitations of strain methodology, due to chest wall abnormality.