eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology
Mitral Valve Insufficiency: Differential Diagnoses & Workup
Updated: Apr 28, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Workup
Imaging Studies
- Chest radiography
- With mild mitral regurgitation (MR), the heart size is normal.
- With increasing MR, cardiomegaly may develop, and left atrial enlargement becomes apparent. Left atrial dilation caused by chronic rheumatic heart disease often includes radiographically apparent dilation of the left atrial appendage. Left ventricle (LV) enlargement and pulmonary congestion may also be present.
- In cases of acute MR, pulmonary venous vasculature markings and pulmonary edema without signs of left atrial enlargement may be increased.
- Echocardiography
- Echocardiography is the most valuable technique used to evaluate MR. Echocardiography is usually readily available and portable. The 2-dimensional echocardiogram allows depiction of the size of the chambers and assessment of ventricular systolic function, as well as determination of the morphology of the mitral valve, the annulus, and papillary muscles.
- Color-flow Doppler echocardiography demonstrates duration and direction of the regurgitant flow.5 Spectral Doppler imaging demonstrates a high-velocity signal across the mitral valve in systole entering retrograde into the left atrium. MR can be seen and evaluated best in the apical 4-chamber and parasternal-long views.
- Visualizing MR is not difficult. Classifying the severity of MR is another issue. In the adult population, many echocardiographic methods are used, all with varying results. The grading of MR in the pediatric population as mild, moderate, and severe is based on the size and extent of the color-flow Doppler signal into the left atrium. Other factors to consider include left atrium and ventricular size and function. In mild MR, the signal is located in the proximal third of the left atrium near the mitral valve. The left atrium is usually not enlarged, and the ventricular function is normal. In moderate MR, the signal is mid cavity, with left atrial dilation and increased ventricular function. With severe MR, the signal reaches the posterior third of the left atrium and the pulmonary veins, and the left atrium and ventricle are usually enlarged, with increased ventricular function.
- The parasternal long axis view may provide the best images of mitral valve prolapse, while the parasternal short axis view is better for depicting papillary muscle anatomy and leaflet cleft.
- Transesophageal echocardiography (TEE): This may be required if further detailed anatomic information is needed. TEE views correlate better with angiographic grading than transthoracic views.
- Echocardiography: This provides a semiquantitative evaluation of MR, but decisions regarding therapy and possible surgical intervention remain dependent on clinical signs and symptoms (ultimately, LV function).
- Cardiac MRI
- Cardiac MRI is a newer modality for imaging the heart. Cardiac MRI provides 3-dimensional imaging of the heart and great vessels and does not depend on acoustic windows, as echocardiography does.
- Cardiac MRI provides more accurate evaluation of both left and right ventricular size and function.
- The degree of MR determined by cardiac MRI has not been adequately evaluated. However, velocity flow imaging may potentially provide additional information.
Other Tests
- The 12-lead ECG is likely to show normal results in children with mild MR.
- In more chronic MR, ECG findings demonstrate left atrial and LV enlargement.
- When pulmonary hypertension is present, ECG may also demonstrate right ventricular hypertrophy.
- Rhythm changes, such as atrial fibrillation, are often observed in adults but are rare in children.
Procedures
- Evaluation of MR in children usually does not require cardiac catheterization. Some pediatric patients undergo catheterization to evaluate other cardiac defects that may be present.
- MR is best evaluated using angiography obtained in the right anterior oblique view. Retrograde flow of injected dye demonstrates the degree of MR, which is quantitatively graded (grades I-IV) depending on the level of left atrial opacification (see below). LV injections obtained via the retrograde approach are preferred to an anterograde approach to prevent the catheter from holding the mitral valve open and creating artefactual MR.
- To quantitate MR, a combination of angiography and cardiac output measurements must be used. Either thermodilution or the Fick principle helps measure forward cardiac output, while angiography allows determination of total LV output. Keep in mind that tricuspid regurgitation can invalidate the thermodilution method.6
- Subtracting the forward output from total LV output yields the regurgitant fraction. A regurgitant fraction of 0.5 or greater is generally considered clinically significant.
- The LV ejection fraction may be increased initially; however, as the LV decompensates, the ejection fraction decreases to normal or subnormal values, signifying LV failure. As LV failure develops, LV end-diastolic pressure increases, resulting in an increase in left atrial and pulmonary venous pressure. Increased pulmonary venous pressure is manifested as an increase in pulmonary capillary wedge pressure. At catheterization, the wedge pressure a wave amplitude is increased along with a rapid rise of the v wave. The latter occurs when LV compliance decreases.
- A study evaluating MR compared cardiac catheterization to echocardiography (transesophageal, transthoracic) and found no advantage to catheterization in clinical decision making. Cardiac catheterization should be used when noninvasive data are discordant, limited, or differ from the clinical status of the patient. Ventriculography may add new information if more complex congenital cardiac problems are present.
- Estimation of mitral regurgitation using angiography is as follows:
- Regurgitation grade of 1+: Trace amounts of contrast are seen in the left atrium, but the amount is insufficient to outline the left atrium.
- Regurgitation grade of 2+: The contrast opacifies the entire left atrium but less than that of the LV. The contrast clears quickly (within 2-3 beats).
- Regurgitation grade of 3+: The contrast opacifies the left atrium and LV equally.
- Regurgitation grade of 4+: The contrast opacifies the left atrium more than the LV and progresses to the pulmonary veins.
More on Mitral Valve Insufficiency |
| Overview: Mitral Valve Insufficiency |
 Differential Diagnoses & Workup: Mitral Valve Insufficiency |
| Treatment & Medication: Mitral Valve Insufficiency |
| Follow-up: Mitral Valve Insufficiency |
| Multimedia: Mitral Valve Insufficiency |
| References |
| Further Reading |
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References
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Further Reading
- Relevant clinical guidelines include the following:
- Guidelines on the management of valvular heart disease
- American College of Cardiology Foundation/American Heart Association 2005 guideline update for the diagnosis and management of chronic heart failure in the adult
- American College of Cardiology/American Heart Association 2006 guidelines for the management of patients with valvular heart disease
- Relevant clinical trials include the following:
- Pivotal Study of a Percutaneous Mitral Valve Repair System
- Comparing the Effectiveness of Repairing Versus Replacing the Heart's Mitral Valve in People With Severe Chronic Ischemic Mitral Regurgitation
- Comparing the Effectiveness of a Mitral Valve Repair Procedure in Combination With Coronary Artery Bypass Grafting (CABG) Versus CABG Alone in People With Moderate Ischemic Mitral Regurgitation
- Related eMedicine topics include the following:
Keywords
mitral valve insufficiency, mitral valve regurgitation, mitral regurgitation, MR, heart defect, congential heart defect, acquired heart defect, mitral valve defect, cardiomyopathy, cardiac disease, cardiac defect, left-sided heart disease, heart failure, pulmonary edema, pulmonary congestion, pulmonary hypertension, failure to thrive, endocarditis, myocarditis, rheumatic heart disease, systemic lupus erythematosus, SLE, ischemic, mitral valve prolapse, Marfan syndrome, Ehlers-Danlos syndrome, coronary artery disease, amyloidosis, sarcoidosis, cardiomyopathy, transposition of the great arteries, anomalous origin of the left coronary artery, scleroderma, hypertrophic cardiomyopathy, treatment, diagnosis
