Atrioventricular Valve Regurgitation Vena Contracta; Echo Versus MRI

BACKGROUND, SIGNIFICANCE, AND RATIONALE (including preliminary studies and any results) The
integrity of the two atrioventricular valves (AVV)(i.e., the mitral and tricuspid valve)
plays an important role in the evaluation and management of patients with congenital and
acquired heart disease. Loss of valve integrity (i.e., valve leakage in the reverse direction
of normal blood flow), is known as valve regurgitation. Increasing severity of mitral
regurgitation has been associated with increased mortality and morbidity. Tricuspid
regurgitation can be a progressive problem that results in right atrial and ventricular
dilation and possible right heart failure. Similarly, mitral valve regurgitation can result
in left atrial and left ventricular enlargement. Treatment options for valvular regurgitation
are based upon the degree of regurgitation in both adults and children. Therefore, assessment
of the degree of AV valvular regurgitation has important clinical ramifications. AV valve
regurgitation can be assessed in several ways, including both invasive and noninvasive
modalities. The invasive assessment is performed by cardiac catheterization which enables
qualitative and quantitative measurements of AV valve regurgitation and in the past has been
considered the "gold standard". Noninvasive assessment is still the preferred method and
consists of echocardiography, electrocardiography, chest x-ray, and CMR. TTE can be used
qualitatively to describe the amount of AV valve regurgitation by the degree of color flow
Doppler reflux into the left atrium during left ventricular contraction. This approach grades
the regurgitation as mild, moderate or severe similar to angiographic grading systems, but is
relatively subjective and affected by technical factors. TTE can quantitatively evaluate AV
valve regurgitation through calculation of regurgitation orifice area, regurgitation volume
and regurgitation fraction. These methods have been shown to have a good correlation when
used for mitral valves compared to cardiac catheterization and CMR in adults. However,
quantitative techniques are time consuming and require multiple measurements and more complex
calculations. A simpler technique of objectively characterizing the regurgitation of the AV
valves by TTE is measuring the width of the vena contracta (VC). The VC is the narrowest
portion of a regurgitant jet which occurs at the level of or just below the valve leaflets
and represents the effective regurgitant orifice. In adult studies, this method has shown
that increase in VC width of the mitral valve strongly correlates with qualitative
angiographic grades and quantitative measurements of regurgitant volume by cardiac
catheterization and is a better assessment of regurgitation than measuring the regurgitant
jet by TTE. Changes in VC width also had strong correlation with quantitative measurements of
regurgitant volume and regurgitant orifice area using TTE. It is our intent to evaluate the
feasibility and correlation of measurements of AV valve regurgitation by TTE with focus on
the VC in pediatric patients compared to the non-invasive "gold standard" measurements by
CMR.

Inclusion Criteria:

- Audible AV valve regurgitation on clinical exam, as noted by most recent clinic note.

- Clinically indicated CMR study scheduled and have had an echocardiogram in the last 6
months

Exclusion Criteria:

- Poor quality CMR study

- Unable to complete a CMR

- Have a contraindication to CMR scan (e.g., pregnancy, pacemaker or defibrillator
presence, unable to hold still within scanner for imaging)

- Common AV valve

- Corresponding semilunar valve regurgitation which precludes use of stroke volume
comparison as a second means of assessing AVV regurgitation by CMR

- Intracardiac shunts which precludes use of stroke volume comparison as a second means
of assessing AVV regurgitation by CMR.