Does chest wall conformation influence myocardial strain parameters in infants with pectus excavatum?

Abstract

To investigate the possible influence of chest wall conformation on myocardial strain parameters in a consecutive population of infants with pectus excavatum (PE), noninvasively assessed by modified Haller index (MHI). Sixteen consecutive PE infants (MHI >2.5) and 44 infants with normal chest shape (MHI ≤2.5) entered in this prospective case-control study. All infants underwent evaluation by neonatologist, transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography (2D-STE) analysis of both ventricles and MHI assessment (ratio of chest transverse diameter over the distance between sternum and spine), at two time points: within 3 days and at about 40 days of life. At 2.1 ± 1 days of life, compared to controls (MHI=2.01 ± 0.2), PE infants (MHI=2.76 ± 0.2) were diagnosed with significantly smaller cardiac chambers dimensions. Biventricular contractile function and hemodynamics were similar in both groups of infants. Left ventricular (LV) global longitudinal strain (GLS) (-16.0 ± 2.8 vs. -21.7 ± 2.2%), LV-global circumferential strain (GCS) (-16.3 ± 2.7 vs. -24.0 ± 5.2%), LV-global radial strain (GRS) (24.2 ± 3.0 vs. 31.5 ± 6.3%), and right ventricular free wall longitudinal strain (RVFWLS) (-16.0 ± 3.2 vs. -22.3 ± 4.4%) were significantly reduced in PE infants versus controls (all p < 0.001). A strong inverse correlation between MHI and the following parameters: LV-GLS (r=-0.92), LV-GCS (r=-0.88), LV-GRS (r=-0.87), and RVFWLS (r=-0.88), was demonstrated in PE infants, but not in controls, in perinatal period (all p < 0.001). Analogous results were obtained at 36.8 ± 5.2 days after birth. Abnormal chest anatomy progressively impairs myocardial strain parameters in PE infants. This impairment might reflect intraventricular dyssynchrony due to compressive phenomena rather than intrinsic myocardial dysfunction.