Biatrial performance in children with hypertrophic cardiomyopathy: CMR study

Abstract

ObjectivesTo investigate biatrial mechanics and their relation with left ventricular outflow tract (LVOT) obstruction (LVOTO), the degree of hypertrophy, indices of ventricular diastolic function and fibrosis in children with hypertrophic cardiomyopathy (HCM).MethodsFifty-five consecutive, prospectively recruited children with HCM (mean age 12.5 ± 4.6 years, 69.1% male), 19 (34.5%) of whom had LVOTO, underwent cardiac magnetic resonance and echocardiography with quantification of phasic components of biatrial function, biventricular diastolic function and fibrosis. Twenty healthy, sex-matched subjects served as controls.ResultsWe found a significant increase of left atrial (LA) and right atrial (RA) volumes and reduction in the majority of indices of contractile function, strains and strain rates (p < 0.05) in children with HCM compared with controls. Nearly all of the LA dynamics markers attained a significant association with the LVOT gradient (p < 0.05), the RA volumes and contractile functions were affected by LV fibrosis and mass (p < 0.05), and the RA mechanical components were related to the degree of LVOTO (p < 0.05). The minority of biatrial dynamics markers were associated with indices of ventricular diastolic function.ConclusionsThe majority of biatrial volumetric and functional indices were severely compromised in children with HCM compared with controls. The degree of LVOTO appears to trigger LA volumetric and LA and RA mechanical malfunction. On the other hand, the deterioration of RA volumetric components was linked to LV fibrosis and mass.Key Points • Biatrial function was severely compromised in children with HCM. • Left atrial malfunction was associated with the degree of LVOTO. • Fibrosis and LV mass were related to RA volumetric and contractile dysfunction. • The degree of LVOTO was linked to right atrial mechanical abnormalities.

The Indices of Cardiovascular Magnetic Resonance Derived Atrial Dynamics May Improve the Contemporary Risk Stratification Algorithms in Children with Hypertrophic Cardiomyopathy

“…The comparisons between baseline clinical, CMR and FT markers in HCM patients and healthy controls were presented elsewhere [ 14 ].…”

“…Authors of the existing works, mostly based on pulmonary hypertension models, accordingly conclude that the decline in compliance of right ventricle is the presumable mechanism of deterioration of RA function [ 19 , 20 ]. Also, not without significance, is backwardly transmitted, through pulmonary circulation, elevated left-ventricular end-diastolic pressure which may additionally decrease RA function [ 14 ]. Moreover, the progressive nature of fibrosis resulted from primary muscle disease can contribute to further deterioration of RA size and function.…”

“…In our cohort, clinical outcomes were not significantly worse in children with LVOT obstruction. However, it was previously demonstrated that left-ventricular [ 21 ] and biatrial performances [ 14 ] were far worse in subjects with LVOT obstruction. The loud murmur produced by obstruction might result in early diagnosis during the routine paediatric examination, which could lead to closer follow up and early-introduced pharmacological treatment.…”

“…Advances in cardiac magnetic resonance (CMR) derived feature tracking (FT) technology has enabled the study of the advanced mechanical components of atrial function. The determinants and magnitude of LA malfunction were previously identified in adults [ 13 ] and children [ 14 ] with HCM. However, the usefulness of CMR-derived LA mechanical indices in risk stratification models have not been validated.…”

Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy: The Utility of Myocardial Strain Based on Cardiac MR Tissue Tracking

“…11,12 Hence, a visually subjective evaluation of LVOT obstruction during MRI is often adopted in current clinical practice. 13 Strain has gradually been proposed as a quantitative assessment of myocardial deformation and dysfunction. 14 Tissue tracking (or feature tracking) is a recently developed technology that uses routinely acquired cine images and can segmentally analyze myocardial mechanics to produce measurements of strain, strain rate, and displacement in the radial, circumferential, and longitudinal directions.…”