[Atrial septal defect associated with mitral valve prolapse--prevalence and clinical significance].

AIM: High incidence of mitral valve prolapse (MVP) associated with atrial septal defect (ASD) has been reported. The study aimed to evaluate the prevalence, etiology and clinical significance of MVP in patients with ASD.
METHODS: Forty-seven consecutive patients with secundum type ASD (30 F; 17 M; mean age: 37.9 +/- 14.0; range: 16-62 years) were enrolled into the study. All patients underwent M-mode and two dimensional echocardiography to check for MVP, defined as the superior systolic displacement of mitral leaflets > or = 2 mm above annulus with coaptation point at, or superior to the annular plane. Pulmonary to systemic flow ratio (Qp/Qs), diastolic right ventricle dimension (RV), left ventricle dimension (LV) and left to right ventricle ratio (LV/RV) were measured. Furthermore, mitral and tricuspid valve insufficiency and right ventricle systolic pressure (RVSP) were evaluated. A symptom-limited, incremental exercise test (CPX)--modo Bruce on Marquette 2000 Treadmill was performed in every patient. We determined: time of exercise--Time (min), peak oxygen uptake--VO2peak (ml/kg/min), VO2peak expressed as % of predicted value--VO2% and anaerobic threshold--AT (expressed as % VO2 max). The study population was divided into two groups: Group I--patients with ASD and MVP and Group II--patients with ASD without MVP.
RESULTS: MVP was recognized in 17 patients (36%); anterior MVP was found in 14, two cases revealed posterior MVP and one was diagnosed with both anterior and posterior MVP. MVP was not associated with significant mitral regurgitation. Echocardiographic and CPX data are summarized in table I. There were no significant differences in age, RVSP, RV and LV diastolic dimensions between groups, although Qp/Qs was significantly higher (p=0.01) and LV/RV significantly lower (p=0.02) in the MVP group. Moreover, there was a significant negative correlation between Qp/Qs and LV/RV ratio (r=-0.70; p<0.001) in a study group. No significant difference in time of exercise, VO2peak, VO2%, and AT was observed between respective groups.
CONCLUSIONS: Our data support the thesis that MVP associated with secundum ASD is a functional disorder due to the atrial shunt and leftward shift of interventricular septum. MVP does not affect cardiopulmonary capacity in ASD patients.