A Reappraisal of the Mitral B-Bump (B-Inflection): Its Relationship to Left Ventricular Dysfunction

A prolonged AC interval, decreased PR - AC interval, and a B-inflection ("bump" or "notch") on the mitral AC slope, have been widely regarded as evidence of abnormally high LVEDP for the last 16 years. However, several groups have questioned the reliability of these signs as predictors of high LVEDP. In 50 patients subjected to LV catheterization, we found no correlation between LVEDP and the AC interval or PR - AC interval. A better correlation was obtained between the presence of a B-inflection and diminished LV ejection fraction on angiocardiography. In our series, the B-inflection was noted in 1/19 patients with LVEDP < 15 mmHg as well as LV ejection fraction > 55%, but it was present in 7/10 patients with LVEDP over 15 mmHg, as well as LV ejection fraction < 55%. When properly recorded, the presence of a B-inflection is a useful sign of significant LV dysfunction.