The impact of cardiac rhythm on the mitral valve area and gradient in patients with mitral stenosis

Association between Mitral Valve Mean Pressure Gradient and Atrial Fibrillation in Patients with Rheumatic Mitral Stenosis: A Cross-Sectional Study

INTRODUCTION

Atrial fibrillation (AF) often occurs in patients with rheumatic mitral stenosis (RMS) and is associated with adverse clinical outcomes. Mitral valve mean pressure gradient (MVMPG) is utilized as an indicator to assess the severity of mitral stenosis and its hemodynamic implications. The aim of this study was to investigate the association between MVMPG and AF in individuals with RMS.

METHODS

We conducted a retrospective analysis of medical records from 360 consecutive patients diagnosed with RMS at the First Affiliated Hospital of Wenzhou Medical University between January 2018 and January 2023. Using both univariate and multivariate logistic regression models, the relationship between MVMPG and AF was evaluated. Restricted cubic splines were employed to test for linearity, and stratified and interaction analyses were performed to evaluate the stability of this relationship among different subgroups.

RESULTS

Based on the MVMPG levels, 360 RMS patients in total were categorized into three groups for the analysis: Q1 (<5 mm Hg), Q2 (5-10 mm Hg), and Q3 (>10 mm Hg). The average age was 60.6 years (Q1: 66.1, Q2: 61.9, Q3: 55.8), and 70.8% were female. The prevalence of AF was 39.6%, 56.5%, and 63.2% in Q1, Q2, and Q3, respectively. After adjusting for potential confounders, a significant association between MVMPG and AF was observed. In Q2, there was a 119% increase in AF (OR 2.19, 95% CI: 1.01-4.75), while in Q3, there was a 238% increase (OR 3.38, 95% CI: 1.39-8.19), compared to Q1. The relationship between MVMPG and AF was linear (p = 0.503). These results remained consistent in each subgroup analysis.

CONCLUSION

Our study reveals a significant positive association between MVMPG and AF in patients with RMS, which holds important clinical implications. It is necessary to conduct further research.

Pulmonary hypertension due to left heart disease causes intrapulmonary venous arterialization in rats

OBJECTIVE

A rat model of left atrial stenosis-associated pulmonary hypertension due to left heart diseases was prepared to elucidate its mechanism.

METHODS

Five-week-old Sprague-Dawley rats were randomly divided into 2 groups: left atrial stenosis and sham-operated control. Echocardiography was performed 2, 4, 6, and 10 weeks after surgery, and cardiac catheterization and organ excision were subsequently performed at 10 weeks after surgery.

RESULTS

Left ventricular inflow velocity, measured by echocardiography, significantly increased in the left atrial stenosis group compared with that in the sham-operated control group (2.2 m/s, interquartile range [IQR], 1.9-2.2 and 1.1 m/s, IQR, 1.1-1.2, P < .01), and the right ventricular pressure-to-left ventricular systolic pressure ratio significantly increased in the left atrial stenosis group compared with the sham-operated control group (0.52, IQR, 0.54-0.60 and 0.22, IQR, 0.15-0.27, P < .01). The right ventricular weight divided by body weight was significantly greater in the left atrial stenosis group than in the sham-operated control group (0.54 mg/g, IQR, 0.50-0.59 and 0.39 mg/g, IQR, 0.38-0.43, P < .01). Histologic examination revealed medial hypertrophy of the pulmonary vein was thickened by 1.6 times in the left atrial stenosis group compared with the sham-operated control group. DNA microarray analysis and real-time polymerase chain reaction revealed that transforming growth factor-β mRNA was significantly elevated in the left atrial stenosis group. The protein levels of transforming growth factor-β and endothelin-1 were increased in the lung of the left atrial stenosis group by Western blot analyses.

CONCLUSIONS

We successfully established a novel, feasible rat model of pulmonary hypertension due to left heart diseases by generating left atrial stenosis. Although pulmonary hypertension was moderate, the pulmonary hypertension due to left heart diseases model rats demonstrated characteristic intrapulmonary venous arterialization and should be used to further investigate the mechanism of pulmonary hypertension due to left heart diseases.