Abstract Body: Background
Diabetic pregnancy (DP) increases cardiovascular disease risk in first generation (F1) offspring. We previously showed that genomic perturbations associated with cardiometabolic dysfunction in DP-exposed F1 rats are passed on to second-generation (F2) embryos.

Hypothesis
DP-exposed F2 rats have programmed changes in cardiac electrophysiology associated with diastolic inflow parameters.

Goals/Aims
To compare F2 ECG metrics and test their association with key F2 echo indices and plasma biomarkers.

Methods/Approach
F0 dams (n=25) were stratified to control (CON) or high-fat diet late-gestation diabetes (DP) groups. F1 pups were cross-fostered at birth to non-diabetic dams, then mated with normal males to generate F2 grand-offspring. At 12 months, F2 underwent echocardiography with simultaneous single-lead ECG capture. Heart rate, PR interval, R-wave amplitude (R), QRS duration, QT/QTc, and ST/J-point height were averaged. A subset (n=40) had plasma troponin, FABP3, and follistatin-1 analyzed by multiplex assay. Group comparisons used sex-adjusted linear regression with standard errors clustered by F0 dam, adjusting for adult body weight and heart rate. Associations used partial Spearman correlations adjusting for sex, body weight, and heart rate.

Results/Data
F2 ECG data from 171 animals (CON 80; DP 91) showed DP-associated differences in PR (-3.35 ms, p=0.04), R (+43.7, p=0.04), and ST/J (-24.3, p=0.003); QRS and QT/QTc were not different. In independent aortic and tricuspid acquisition views, higher R (+76.6, p=0.0006; +78.2, p=0.015) and more negative ST/J height (-31.9, p=0.007) were reproduced. DP F2 had lower mitral inflow: MV E and A decreased with higher E/A (all p ≤0.001). Ejection fraction was not different. Follistatin-1 levels were also lower (sex-adjusted log p=0.008). Within DP, ST/J correlated with MV E (ρ=-0.262; p=0.01), IVSd (ρ=0.228; p=0.03), and LV mass (ρ=0.224; p=0.03).

Conclusions
DP yields a reproducible ECG-detected phenotype (PR shortening, more negative ST/J height) and lower follistatin-1 levels in F2 grand-offspring along with altered diastolic inflow, supporting multigenerational reprogramming of cardiac electrical physiology and diastolic function.