AUTHOR=Al-Wakeel-Marquard Nadya , Seidel Franziska , Kühnisch Jirko , Kuehne Titus , Berger Felix , Messroghli Daniel R. , Klaassen Sabine 

TITLE=Midwall Fibrosis and Cardiac Mechanics: Rigid Body Rotation Is a Novel Marker of Disease Severity in Pediatric Primary Dilated Cardiomyopathy

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 8 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.810005

DOI=10.3389/fcvm.2021.810005

ISSN=2297-055X

ABSTRACT=Background:
Midwall fibrosis (MWF) detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) predicts adverse outcome in adults with dilated cardiomyopathy (DCM). Its relevance in children and adolescents is relatively unknown. Left ventricular (LV) strain, rotation and twist are important parameters of cardiac function; yet, their role in pediatric heart failure is understudied. This study aimed to evaluate MWF and cardiac mechanics in pediatric DCM.

Methods:
Patients ≤21 years with primary DCM were prospectively enrolled and underwent standardized CMR including LGE. All participants were categorized according to the presence or absence of MWF (MWF+ vs. MWF-). Cardiac mechanics were assessed using CMR feature tracking. Impaired LV twist with apex and base rotating in the same direction was termed rigid body rotation (RBR). 

Results: 
In total, 17 patients (median age 11.2 years) were included. MWF was present (MWF+) in seven patients (41%). Median N-terminal pro brain natriuretic peptide (NT-proBNP) was higher (5959 vs. 242 pg/ml, p=0.887) and LV ejection fraction (LVEF) lower (28 vs. 39%, p=0.536) in MWF+ vs. MWF- patients, yet differences were not statistically significant. MWF+ patients had reduced global longitudinal (GLS), circumferential (GCS) and radial strain (GRS), again without statistical significance (p=0.713, 0.492 and 1.000, respectively). A relationship between MWF and adverse outcome was not seen (p=0.637). RBR was more common in MWF+ (67 vs. 50%), and was associated with the occurrence of adverse events (p=0.041). Patients with RBR more frequently were in higher NYHA classes (p=0.035), had elevated NT-proBNP levels (p=0.002) and higher need for catecholamines (p=0.001). RBR was related to reduced GLS (p=0.008), GCS (p=0.031), GRS (p=0.012), LV twist (p=0.008), peak apical rotation (p<0.001), and LVEF (p=0.001), elevated LVEDV (p=0.023) and LVESV (p=0.003), and lower RVSV (p=0.023). 

Conclusions:
MWF was common, but failed to predict heart failure. RBR was associated with clinical and biventricular functional signs of heart failure as well as the occurrence of adverse events. Our findings suggest that RBR may predict outcomes and may serve as a novel marker of disease severity in pediatric DCM.


Clinical trial registration:
https://clinicaltrials.gov/; ClinicalTrials.govIdentifier: NCT03572569