Cardiomyocyte deoxyribonucleic acid damage and cardiac recovery in pediatric dilated cardiomyopathy.

OBJECTIVES: This study aimed to identify the clinical significance of the deoxyribonucleic acid damage response marker, phosphorylated H2A histone variant X, on the bridge to recovery in low-weight pediatric patients with dilated cardiomyopathy post-Berlin Heart EXCOR implantation.

METHODS: Consecutive pediatric patients with dilated cardiomyopathy who underwent EXCOR implantation for dilated cardiomyopathy at our hospital between 2013 and 2021 were reviewed. Patients were classified into two groups according to the degree of deoxyribonucleic acid damage in left ventricular cardiomyocytes-low deoxyribonucleic acid damage group and high deoxyribonucleic acid damage group-using the median value as the threshold. We examined and compared the preoperative factors and histological findings associated with cardiac functional recovery following explantation in the two groups.

RESULTS: Competing outcome analysis of 18 patients (median body weight, 6.1 kg) showed that the incidence of EXCOR explantation was 40% at 1 year after implantation. Serial echocardiography revealed significant left ventricular functional recovery in the low deoxyribonucleic acid damage group 3 months after implantation. The univariable Cox proportional-hazards model revealed that the percentage phosphorylated H2A histone variant X positive cardiomyocyte was the significant factor associated with cardiac recovery and EXCOR explantation (hazard ratio, 0.16; 95% confidence interval, 0.027-0.51; P = 0.0096).

CONCLUSIONS: The degree of deoxyribonucleic acid damage response at EXCOR implantation may aid in predicting the bridge to recovery with EXCOR among low-weight pediatric patients with dilated cardiomyopathy.