Left atrioventricular coupling in isolated pediatric mitral valve prolapse with preserved ejection fraction and moderate regurgitation.

This study aimed to study the coupling between the left ventricle and left atrium in pediatric patients with mitral valve prolapse (MVP) by utilizing strain parameters and the left atrioventricular coupling index (LACI). A retrospective analysis was conducted over six years to identify patients with MVP and moderate mitral regurgitation who had undergone cardiac MRI. The study included 20 patients and 20 healthy controls. Functional and strain assessments of the left ventricle (LV), right ventricle (RV), and left atrium (LA) were performed and compared to those of healthy controls. LACI was determined by calculating the ratio of the LA end-diastolic volume indexed to the left ventricular end-diastolic volume indexed, and it was correlated with conventional CMR and strain parameters. Native T1 mapping was used as a non-contrast CMR technique to assess diffuse myocardial fibrosis in all patients. LACI revealed a negative correlation with left ventricular end-diastolic volume indexed to body surface area (LVEDVI) and total left atrial ejection fraction (LAEF) (r = -0.39, -0.65, P < 0.05, respectively). In addition, LACI showed a correlation with strain parameters, specifically with LA longitudinal peak positive strain rate and left ventricular global circumferential strain (LV GCS) (r = 0.35, -0.49, P < 0.05, respectively). The results from the multivariate regression analysis indicated that the left atrial longitudinal reservoir strain (ξs) was independently associated with left ventricular ejection fraction [β = 0.529; 95% confidence intervals (CI) = 0.192 to 0.866] and LV GRS [β = 0.229; 95% CI = 0.128 to 0.330]. There were statistically significant differences in LACI and LA ξs between patients who experienced clinical events such as arrhythmia and those who did not, with p-values of < 0.05. Strain parameters showed better results in evaluating LA and LV coupling in our patient group. Elevated native T1 values correlated with LACI, impaired LV, and LA strain parameters.