In the era of increasingly successful corrective interventions in patients with congenital heart disease (CHD), global and regional myocardial remodeling are emerging as important sources of long-term morbidity/mortality. Changes in organization of the myocardium in CHD, and in its mechanical properties, conduction, and blood supply, result in altered myocardial function both before and after surgery. To gain a better understanding and develop appropriate and individualized treatment strategies, the microscopic organization of cardiomyocytes, and their integration at a macroscopic level, needs to be completely understood. The aim of this study is to describe, for the first time, in 3 dimensions and nondestructively the detailed remodeling of cardiac microstructure present in a human fetal heart with complex CHD.

This study was partially supported by the Spanish Ministry of Economy and Competitiveness (grant TIN2014-52923-R and the Maria de Maeztu Units of Excellence Programme - MDM- 2015-0502) and FEDER. CB is supported by Fundació La Marató de TV3 (Spain), grant Nº: 20154031. JAS is supported by the Center of Excellence CompBioMed funded under H2020-EU.1.4.1.3. under grant agreement Nº 675451. DJS is supported by the British Heart Foundation under the grant Nº FS/15/33/31608.