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[Doppler echographic evaluation of mitral valve stenosis with atrial fibrillation. Construction of a nomogram]
L Christiaens1, D Coisne, P Bru
1Service de cardiologie A, CHU de Poitiers La Milétrie, Poitiers.
Insights
Doppler echocardiography can assess mitral stenosis in atrial fibrillation. A new method uses transmitral pressure gradients and cardiac cycle length to accurately determine mitral valve area, aiding diagnosis.
Area of Science:
- Cardiology
- Echocardiography
- Cardiac Physiology
Background:
- Doppler echocardiography is crucial for evaluating mitral stenosis.
- Atrial fibrillation complicates accurate Doppler assessment of mitral stenosis.
- Reliable methods are needed to quantify mitral valve area in these patients.
Purpose of the Study:
- To develop a novel method for assessing mitral valve area in patients with mitral stenosis and atrial fibrillation.
- To establish a correlation between pressure gradients and cardiac cycle length for mitral stenosis evaluation.
- To create a practical tool for improving diagnostic accuracy.
Main Methods:
- Transthoracic Doppler echocardiography was performed on 16 patients.
- Transmitral end-diastolic pressure gradients and RR intervals were analyzed.
- Mitral valve surface area was calculated using the pressure half-time method and simplified Bernoulli formula.
Main Results:
- A significant linear relationship was found between end-diastolic mitral gradient and RR interval duration.
- The slope and intercept of this relationship strongly correlated with mitral valve surface area (p < 0.002 and p < 0.00001).
- A nomogram was developed based on these correlations.
Conclusions:
- The developed nomogram facilitates accurate Doppler evaluation of mitral stenosis in atrial fibrillation.
- This method provides a reliable way to determine mitral valve area despite irregular heart rhythms.
- The findings improve diagnostic capabilities for mitral stenosis in complex cardiac conditions.
Abstract:
Doppler echocardiographic evaluation of mitral stenosis is often difficult in patients with atrial fibrillation. Sixteen patients were examined by transthoracic Doppler echocardiography and the relation between the variations in transmitral end diastolic pressure gradient and the length of the corresponding cardiac cycles was analysed. Mitral valve surface area (1.65 +/- 0.73 cm2) was determined by the pressure half-time method. The end diastolic transmitral pressure gradient was calculated from the simplified Bernouilli formula applied to end diastolic mitral flow velocity. In each patient, a linear relationship was observed between the end diastolic mitral gradient and the corresponding RR interval. The slope and intercept of the graph correlated significantly to mitral valve surface area (r = 0.72, p < 0.002 and r = 0.93, p < 0.00001, respectively). Using regression equations describing these correlations, it has been possible to construct a nomogramme indicating mitral valve surface area as a function of mitral end diastolic pressure gradient and the duration of the corresponding RR cycle. This nomogramme facilitates Doppler evaluation of mitral stenosis in atrial fibrillation.