Mean arterial pressure (MAP) has traditionally been derived from systolic and diastolic pressures, weighted 1/3 systolic and 2/3 diastolic. No correction is made for the increasing time dominance of systole with increasing heart rates. In a previous study, we developed a new and more accurate heart rate-corrected MAP formula from central aorta pressure determinations in a large number of patients: MAP = DP + [0.33 + (HR x 0.0012)] x [PP] where SP and DP are systolic and diastolic pressure and HR is heart rate. The current study validates the new MAP formula in the same patient at increasing paced heart rates. A central aorta catheter was used to obtain computer-determined systolic, diastolic, and MAP in 12 patients. Values were obtained at baseline and then at increasing right atrial paced heart rates. The new and standard MAP formula-derived values were compared with computer-determined values. The new formula showed a much closer correlation with the computer-derived values for MAP. Standard MAP calculations for MAP can easily be improved by inclusion of a heart rate factor.

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This study suggests that PWS is greater in symptomatic or ruptured AAA than in asymptomatic intact AAA.