Cardiac magnetic resonance and genetics in pediatric heart failure patients with nonischemia: prognostic implications.

Background: The associations among genetic variants, cardiac magnetic resonance (CMR) features, and prognostic factors of pediatric heart failure (HF) remain unknown. This study aimed to explore the relationship between genetic differences in pediatric HF and CMR findings and their impact on prognosis of HF in children.

Methods: This retrospective study included children with a first-time diagnosis of HF. All patients underwent echocardiogram, CMR and genetic testing. The cohort was divided into three subgroups according to late gadolinium enhancement (LGE) on CMR: the no LGE subgroup, the subendocardial LGE subgroup, and the nonsubendocardial subgroup. The endpoint was defined as a lack of improvement in HF on echocardiography after more than six months of follow-up.

Results: Ninety-five children with HF were included, of whom 64 underwent genetic testing and 89 had echocardiograms at follow-up. There were 20 patients in the no LGE group, 31 in the subendocardial group, and 44 in the nonsubendocardial group. The most common genotype was MYH7 (27.0%). RBM20 and LMNA both presented a dilated phenotype, whereas GTPBP3 uniformly presented a hypertrophic phenotype. TNNI3 showed no LGE on CMR (P = 0.003) and maintained a restrictive phenotype. The subendocardial group was more likely to have septal LGE (93.5%, P < 0.001). Multivariable regression analysis indicated that a family history of cardiomyopathy, hydropericardium, and right ventricular ejection fraction (RVEF) were independent predictors of the endpoint event (P = 0.035, P = 0.005 and P = 0.032, respectively). Notably, nonsubendocardial LGE was associated with a worse prognosis than no LGE was (P = 0.030).

Conclusions: In pediatric non-ischemic HF patients, subendocardial LGE can be observed. A family history of cardiomyopathy, hydropericardium, and RVEF were predictors of HF with no improvement. The prognosis of HF is associated with the presence of LGE, particularly nonsubendocardial LGE, and less so with the genetic phenotype.