Estimation of pulmonary capillary wedge pressure from M-mode mitral echograms

We investigated whether the isovolumic relaxation time (IRT) and an interval from the start of opening to the maximal amplitude of the anterior mitral leaflet in early diastole (D-E interval) would be useful predictors of the pulmonary capillary wedge pressure (PCWP). We recorded M-mode mitral echograms and phonocardiograms in 33 patients (aged 38-70 years) with acute myocardial infarction (AMI) in the coronary care unit and in 34 patients (aged 40-75 years) with prior myocardial infarction (OMI) during cardiac catheterization. All patients underwent the insertion of a flow-directed pulmonary artery catheter to obtain the PCWP. We measured the IRT and the D-E interval from the phonocardiograms and the M-mode echograms. There was no significant correlation between the IRT and the mean PCWP (mPCWP) in patients with AMI and in patients with OMI. The D-E interval was significantly and inversely correlated with the mPCWP (r = -0.91, p <0.0001) in all patients. The regression equation was mPCWP = -0.42 x (D-E) +47.9. The D-E interval of < or = 75 ms indicated a high mPCWP (mPCWP > or = 18 mm Hg) with high sensitivity (96%) and specificity (88%). The derived equation was tested in a prospective group of 32 additional patients (aged 43-75 years). A significant correlation was observed between the predicted and measured mPCWP (r = 0.91, p <0.0001). Thus, the PCWP can be estimated by using the D-E interval derived from M-mode mitral echograms in patients in the coronary care unit and in patients with chronic heart disease.