EROA Mitral Regurgitation Calculator

Effective regurgitant orifice area, commonly abbreviated EROA, estimates the functional size of the opening through which blood leaks backward across the mitral valve during systole. It is a quantitative echocardiographic measure used alongside regurgitant volume, vena contracta width, pulmonary vein flow, chamber size, symptoms, and other findings. A larger effective opening generally indicates a greater burden of mitral regurgitation. The value is expressed in square centimeters and helps clinicians describe severity consistently, follow change over time, and discuss whether closer surveillance or intervention may be appropriate. This calculator applies the continuity relationship EROA = regurgitant volume divided by the velocity time integral of the regurgitant jet. Regurgitant volume is entered in milliliters, which is equivalent to cubic centimeters, and VTI is entered in centimeters. Dividing volume by distance therefore produces an area in square centimeters. For example, a regurgitant volume of 45 mL and a VTI of 150 cm gives an EROA of 0.30 cm². Peak velocity and heart rate can be recorded for context, but they are not variables in this specific calculation. Common reference bands classify EROA below 0.20 cm² as mild, 0.20 through 0.39 cm² as moderate, and 0.40 cm² or greater as severe primary mitral regurgitation. These bands are useful summaries rather than stand-alone treatment rules. Thresholds and prognostic meaning can differ for secondary mitral regurgitation, acute disease, eccentric jets, multiple jets, or changing loading conditions. Clinical decisions should integrate valve anatomy, ventricular dimensions and function, pulmonary pressure, rhythm, exercise capacity, symptoms, and the quality of the source images. Measurement technique matters. Regurgitant volume and VTI should come from compatible beats and a standardized echocardiographic acquisition. In atrial fibrillation, averaging representative beats may reduce variability. Eccentric or noncircular jets can make assumptions less reliable, while poor Doppler alignment may distort VTI. If the result conflicts with the rest of the examination, clinicians generally repeat measurements or use complementary methods such as three-dimensional echocardiography or cardiac magnetic resonance. The result is intended for education and arithmetic verification, not diagnosis. Do not use it to make treatment decisions without qualified interpretation. New breathlessness, chest discomfort, fainting, pulmonary edema, or rapidly worsening symptoms require prompt medical assessment regardless of a calculated category.