Is experienced pregnancy in women with repaired tetralogy of Fallot related to diffuse myocardial fibrosis?

Objectives: To assess the impact of pregnancy on cardiac function and fibrosis by cardiovascular magnetic resonance (CMR) in patients with repaired Tetralogy of Fallot (rToF).

Background: CMR T1 mapping can assess diffuse myocardial fibrosis which is associated to adverse clinical outcomes. Right ventricular (RV) accelerated remodeling is reported in rToF women with experienced pregnancy.

Methods: We included rToF women from the national registry of congenital heart disease to perform CMR, assessing functional data, T1 mapping/ extracellular volume fraction (ECV). The results including clinical data were compared between women with experienced pregnancy vs non-experienced pregnancy and healthy individuals.

Results: Fifty rToF women performed CMR, median age 36 (range 21-67) years. Fifteen were nulliparous. T1 mapping was compared to 30 controls, (14 women) median age 42 (24-64) years. In the left ventricle (LV), T1 times and ECV in all rToF women vs female controls were 1248 ± 61 ms/ 25.8 ± 2.9% vs 1255 ± 40 ms/ 26.8 ± 3.1%, p = 0.7 and p = 0.3, respectively. In rToF, RV T1 times was 1385 ± 124 ms and ECV 37.7 ± 5.4%. There was no association to parity or age in rToF LV T1/ ECV, p = 0.9 for both, or RV T1/ECV, p = 0.4 and p = 0.6, respectively. Indexed LV mass was higher in the rToF pregnancy group, 43 ± 10 vs 38 ± 6 g/m, p = 0.03 while RV ejection fraction was lower, 49 ± 7% vs 53 ± 6%, p = 0.04.

Conclusion: Women with rTOF showed evidence of increased RV CMR markers suggestive of diffuse fibrosis while LV CMR markers were within normal values. Having experienced pregnancy might affect RV function, however without association to CMR biomarkers.