Estimation of Left Ventricular Systolic Function Using Volume-Normalized Contractility Measures in Patients with Acute Myocardial Infraction

摘要

We propose three cardiac size-normalized contractility indexes in the work to investigate whether left ventricular (LV) systolic function in patients with acute myocardial infraction (AMI) after thrombolysis is enhanced or not. A cohort of 18 patients (17 men) aged 45-72 years received thrombolytic therapy within 24 hours after an AMI event, and their LV chamber function was determined using pressure-volume loops obtained by simultaneous conductance catheter volumetry and micromanometer pressure during catheterization examination at the first week and 3 months, respectively. A slope of the end-systolic pressure volume relation (Ees) was derived by reduced venous return. Three new contractility indexes (Esv, Edv, and Emv) were defined as the Ees divided by the end-systolic volume, end-diastolic and midrange of the LV volume, and then normalized to 100 ml, respectively. Using linear regression methods, we found high correlation coefficients of r=0.835 at the first week and r=0.826 at 3 months between the Ees and Esv after thrombolysis. Furthermore, Esv and Emv but not Ees were significantly higher measured at 3 months than at the first week after thrombolytic intervention. Thus, an increase in the volumenormalized contractility measures Esv and Emv implies the improvement of the left ventricular systolic function in the post-AMI human hearts long-term after thrombolytic treatment, in despite that there is a great coefficient of variation in cardiac chamber sizes at different recovery stages.