To explore whether left atrial (LA) size and function influence secondary tricuspid regurgitation in patients with rheumatic mitral stenosis.

Sixty-seven patients diagnosed with moderate or severe rheumatic mitral stenosis from February 2015 to February 2017 at Fuwai Hospital were enrolled in our study. All patients underwent mitral valvular replacement and preoperative echocardiography. Secondary tricuspid regurgitation occurred in all patients. Twenty outpatients were enrolled as normal controls in our study and they also underwent echocardiography. Various echocardiography parameters and LA function were compared between the patients and normal controls. The correlations among LA function, tricuspid valvular morphology and function, and the influencing factors of secondary tricuspid regurgitation were analyzed.

LA fraction of area change, LA ejection fraction, and average LA strain were strongly negatively correlated with tricuspid annular diameter index (r=-0.65, -0.58, and -0.59, respectively; P<0.01) and pulmonary artery systolic pressure (r=-0.60, -0.58, and -0.59, respectively; P<0.01). Logistic regression analysis demonstrated that tricuspid annular diameter index, leaflet tethering distance, and pulmonary artery systolic pressure were influencing factors of secondary tricuspid regurgitation (OR=1.916, 2.382, and 1.059; 95%CI: 1.18-3.109, 1.312-4.323, and 1.009-1.111, respectively; P<0.05). Logistic regression also showed that pulmonary artery systolic pressure, LA fraction of area change, and average LA strain were risk factors for increased tricuspid annular diameter index (OR=1.044, 0.875,and 0.809; 95%CI: 1.002-1.088, 0.761-0.964, and 0.656-0.997, respectively; P<0.05).

Secondary tricuspid regurgitation is influenced by enlarged LA and decreased LA function. Decreased LA fraction of area change and average LA strain can lead to tricuspid annular diameter dilatation, and induce or worsen secondary tricuspid regurgitation. Two dimensional speckle tracking technique could provide early information of LA function.