Abstract Body (Do not enter title and authors here): Objectives:
This study aimed to investigate the potential of ventriculo-arterial coupling (VAC) as a marker of early right ventricular (RV) dysfunction in a porcine model of chronic pulmonary regurgitation following transannular patch repair of pulmonary stenosis.

Background:
Pulmonary regurgitation is a common consequence following the repair of right ventricular outflow tract malformations, such as Tetralogy of Fallot, and can lead to heart failure. Early detection of RV dysfunction remains challenging, and current clinical markers have limited predictive value to identify which patients are at risk and require interventions.

Methods:
Neonatal swine were subjected to pulmonary artery banding to induce RV pressure overload, followed by transannular patch repair (rTAP, n=10) to create chronic pulmonary regurgitation, and were compared to Sham animals (n=6). Longitudinal hemodynamic assessments, including pressure-volume analysis and cardiac magnetic resonance imaging, were performed. VAC was defined as the ratio of end-systolic elastance (Ees) to effective arterial elastance (Ea).

Results:
Over the follow-up period of 4 months, VAC was preserved in the rTAP group. Ea was significantly lower in rTAP animals (P=0.001), while Ees remained unchanged. Lower end-diastolic pulmonary artery pressures and increased early systolic ejection were observed in rTAP, correlating with higher VAC.

Conclusions:
VAC remains preserved in chronic pulmonary regurgitation due to decreased afterload, making it unsuitable as an early marker for RV dysfunction. Low afterload, a consequence of diastolic emptying of the pulmonary artery into the RV, may pseudo-normalize systolic function. Alternative markers e.g. focusing on diastolic RV function and atrio-ventricular interactions should be investigated.