Margerey (J Path Bact 1949; 61:203-208) studied 250 mitral valves and postulated that the mechanism of formation is intimal damage due to mechanical trauma at the leaflet coaptation. The damaged area is covered by fibrin, which subsequently becomes uplifted, or partially detached from the valve surface.
Irving, TX Current Weather and Forecast. Irving, TX Weather Forecast. 3:20 PM CDT SAT APR 15 2017. TONIGHT - Partly cloudy this evening - then becoming mostly cloudy. Lows in the mid 60s. South winds 5 to 10 mph.
In some years the heat can get quite extreme. Dallas has seen many days of 105-110 degree weather, with an all-time high of 113 degrees. According to NOAA, the Dallas area averages 18 days of 100+ degree weather per year, with the most occurring in August (9.2 days) and July (6.0 days).