Echocardiography: pericardial tickening and constrictive pericarditis.

To evaluate the relation between mitral valve motion and left ventricular end-diastolic pressure, the PR-AC interval, an index derived from the electrocardiogram and mitral echogram, and the left ventricular endodiastolic pressure were determined simultaneously in 22 patients undergoing diagnostic cardiac catheterization. Intravenous infusion of dextran or administration of nitroglycerin was used to alter left ventricular end-diastolic pressure to determine if there was a predictive relation between this pressure and the PR-AC interval during acute hemodynamic manipulations. There was a weak negative correlation (r = -0.33, P less than 0.01) between this pressure and the PR-AC interval. At rest a PR-AC interval greater than 0.06 second correctly predicted a left ventricular end-diastolic pressure of less than 20 mm Hg in 15 of 16 subjects. However, in four of six subjects with a PR-AC interval of 0.06 second or less, the end-diastolic pressure was less than 20 mm Hg. After interventions that varied left ventricular end-diastolic pressure by a factor of 2, the PR-AC interval changed slightly or not at all. These data suggest that the PR-AC interval is of limited value in predicting abnormal values or serial changes in left ventricular end-diastolic pressure.