Index of Myocardial Performance in Evaluation of Left Ventricular Function in Patients with Coronary Artery Disease

The index of myocardial performance (IMP) has been used as an easily obtainable parameter which reflects both systolic and diastolic functions of the myocardium and which correlates closely with invasive measurements. The aim of this study was to investigate the importance on assessment of left ventricular functions in patients with severe coronary artery disease. We studied 82 cases who had coronary angiography and echocardiography; Group A without coronary stenosis (n=37, 17 F ve 20 M, mean age 54±11 years) and Group B who had severe coronary stenosis (>% 70) without previous myocardial infarction (n=45, 18 F ve 27 M, mean age 57 ± 10 years). Using echocardiographic parameters, left ventricular isovolumetric relaxation time (IVRT), isovolumetric contraction time (IVCT), ejection time (ET), ratio of velocity time integrals of early and Iate diastolic mitral flow (E/Avti), E deceleration time (EDT), IMP [(IVRT+IVCT)/ET], ejection fraction (EF) and fractional shortening (FS) were calculated. During cardiac catheterization Dp/Dt [(diastolic blood pressu re - left ventricular end diastolic pressure)/IVCT] was calculated.
RESULTS
There were significant differences in IVRT, EDT, E/Avti and the IMP between the Group A and B (95,9±14,7 and 113,4± 14,3 msec , p<0,001; 164,5 ±44,8 and 186,2±33,6 msec, p<0,05; 1,51±0,45 ve 1,24±0,80, p<0,05; 0,45±0,08 and 0,53±0,07, p<0,001 , respectively), but there were no significant differences in IVCT, ET, EF, FS and Dp/Dt between the two groups. There were no significant differences in heart rate, systolic and diastolic blood presssures between the two groups.
CONCLUSION
These data suggest that IMP may be a useful parameter and an early indicator of left ventricular dysfunction in patients with severe coronary artery disease and normal systolic function.