New Techniques to Evaluate Mitral Regurgitation

New Techniques to Evaluate Mitral Regurgitation

Background:

- Mitral regurgitation, or leaking of the mitral heart valve, is usually studied and assessed with an ultrasound test called a two-dimensional (2D) echocardiogram. While this test has proved very useful, technological improvements have helped researchers develop ways to study the heart valves using imaging with three-dimensional (3D) capabilities. In addition, recently developed magnetic resonance imaging (MRI) techniques may be able to provide better information about the causes and severity of the leak. Researchers are interested in testing these new techniques to determine their usefulness for patients with mitral regurgitation.

Objectives:

- To evaluate newer methods of studying mitral regurgitation severity using real-time 3D echocardiography (RT3DE) and cardiac magnetic resonance imaging (CMRI).

Eligibility:

- Individuals at least 21 years of age who have been diagnosed with more than mild mitral regurgitation.

Design:

• Participants will have two procedures as part of this study: an echocardiogram and an MRI scan.
• For the echocardiogram, participants will have an ultrasound scan with a special kind of probe. Participants may also receive an injection of a contrast agent to provide a better image of the heart on the scan. The scan will take approximately 1 hour to complete.
• For the MRI scan, participants will have a standard MRI with special pads placed on the chest to provide better imaging of the heart. The scan will usually take between 45 and 90 minutes to complete.

Echocardiography is currently the technique of choice to assess the etiology and severity of mitral regurgitation (MR). Multiple 2D and Doppler parameters are assessed in an integrated fashion and the proximal flow convergent zone of the mitral regurgitation jet is used to calculate effective regurgitant orifice area and regurgitant volume. These measurements have been shown to have important prognostic information. In the last two years, the development of transesophageal imaging with 3D capability has allowed a better visualization of mitral leaflet pathology. Color Doppler 3D studies have shown that 2D methods generally underestimate mitral regurgitant volume. Magnetic resonance techniques have recently been developed to quantitate flow and calculate regurgitant volumes.

The purpose of this study is to evaluate newer methods of quantitating mitral regurgitation severity using real-time 3D echocardiography (RT3DE) and cardiac magnetic resonance imaging (CMR). Although RT3DE measurements have been shown to correlate well with CMR measures of LV volumes, using a 3D volumetric method to calculate mitral regurgitant volumes has not been well studied. In patients with more than mild mitral regurgitation, we will obtain transthoracic RT3DE measures of mitral regurgitant volume and compare them with traditional 2D measures of MR severity. We will also compare RT3DE and CMR measures of mitral regurgitant volume.

• INCLUSION CRITERIA:
• Adult patient, age greater than or equal to 21 years
• Able to give written informed consent
• Prior cardiac testing clinically read as having greater than mild MR

EXCLUSION CRITERIA:

• Atrial fibrillation or other irregular rhythm that would preclude adequate 3D image acquisition
• History of valve surgery or significant valve disease other than mitral regurgitation
• Patients with pacemakers, defibrillators, cerebral aneurysm clips, neural stimulators, ear implants or other clinical contra-indications for magnetic resonance scanning will be excluded from the CMR portion of the study
• Any unstable condition that would make additional imaging time inadvisable (in the opinion of the investigator or managing physician)
• Pregnant or lactating women