Table 1.
Main characteristics of healthy phenotypes of fetal and adult right ventricles.
| Characteristics | Fetal phenotype | Adult phenotype |
|---|---|---|
| Environment | ||
| Oxygen environment | Low | High |
| Main blood circulation | Placental circulation | Systemic circulation |
| Ductus arteriosus | Opened | Closed |
| PVR | High | Low |
| Main vascularized heart regions | Right ventricular free wall, Right side of the IVS | Left ventricular free wall, Left side of the IVS |
| Systemic ventricle | Right ventricle | Left ventricle |
| Genetics | ||
| Gene pattern expression | β-MHC | α-MHC |
| Metabolic features | ||
| Mitochondrial function | Normal/adapted | Normal/adapted |
| mROS production | Adapted to heart activity | Adapted to heart activity |
| Energetic substrates | Carbohydrates | Fatty acids |
| Hypoxia-induced factors | ||
| (i) HIF1α (ii) VEGF |
Expressed | Not expressed |
| Ca2+ homeostasis | Immature | Mature |
| Cellular features | ||
| Myocytes diameter | 5–7 µm | 15–25 µm |
| Myocytes/nonmyocytes ratio | 30% | 70% |
| Sarcomeres | Disoriented | Parallel |
| Capillary density | Preserved | Preserved |
| Fibrosis | Absent | Absent |
PVR: pulmonary vascular resistance; MHC: myosin heavy chain; mROS: mitochondrial reactive oxygen species; HIF-1α: hypoxia inducible factor 1 alpha; VEGF: vascular endothelial growth factor; Ca2+: calcium.