Transthoracic echocardiography (TTE) in a patient with valvular heart disease is appropriate when there is a change in clinical symptoms. This patient has had worsening dyspnea on exertion for the past 3 weeks that may be a result of worsening mitral regurgitation. In patients with myxomatous mitral valve disease, rupture of a primary or secondary chordae may cause an acute change in the degree of mitral regurgitation and change in clinical status; this is the likely cause of this patient's worsening symptoms. Other causes of her progressive shortness of breath could also be evaluated with an echocardiogram. For example, new wall motion abnormalities could signal recent silent myocardial infarction, and changes in overall ejection fraction would prompt evaluation for new cardiomyopathies.

Exercise stress testing may be appropriate if TTE does not reveal a structural cause of her shortness of breath. In addition to evaluating for obstructive coronary artery disease, stress echocardiography could be used to evaluate changes in mitral regurgitation and pulmonary pressures with exercise. However, a TTE at rest should be obtained before deciding whether a stress test is warranted.

This patient's mitral regurgitation increases her risk for atrial fibrillation. However, her baseline electrocardiogram demonstrates sinus rhythm, so paroxysmal atrial fibrillation as a cause of her dyspnea is less likely. In addition, she has had progressive dyspnea on exertion that has not waxed and waned, as might be expected if she was in and out of atrial fibrillation. The fact that she presents with worsening symptoms and is in sinus rhythm makes paroxysmal atrial fibrillation less likely. Therefore, 24-hour ambulatory electrocardiographic monitoring would not be the best choice for this patient.

This patient does not appear to have active asthma symptoms or changes in pulmonary status that would indicate a need for spirometry at this time.

Transesophageal echocardiography may be helpful in further defining the anatomy, particularly if surgical intervention is planned, but should not be the first diagnostic study. If the cause of the valvular disorder or degree of regurgitation is unclear from the TTE, then transesophageal echocardiography may be appropriate.