INFLUENCE OF MYOCARDIAL STUNNING ON THE DYNAMICS OF THE INDICATORS OF MITRAL REGURGITATION AND REMODELING AFTER MYOCARDIAL INFARCTION

Abstract

Aim. To study the dynamics of mitral regurgitation depending on the results of low dose dobutamine
stress-echocardiography with effectiveness of myocardial reperfusion and in patients after MI with ST
segment elevation.
Material and methods. The study included 302 patients with STeMI. All patients underwent myocardial
reperfusion. Depending on the effectiveness of reperfusion, the patients were divided into 3 groups: group
1 – 196 (65%) patients with successful reperfusion; group 2 – 76 (25%) patients with partial reperfusion,
group 3 – 30 (10%) patients with no reperfusion. The indicators of systolic function, LV remodeling, mitral
regurgitation at rest, under pharmacological load and after a month were studied. To determine the zone
of viable myocardium, stress echocardiography with low doses of dobutamine was used.
Results. Indicators characterizing the severity of MR had a negative trend in patients of group 3, who showed
an increase in ERO, PISA and vena contracta width. But in patients of the 1st and 2nd groups with the presence of myocardial stunning, an unreliable decrease in these indicators of the degree of MR was noted. Identification of viable zones by low-dose dobutamine stress echocardiography in areas of LV dysfunction prevents
the progression of MR and serious intracardiac hemodynamic disturbances and will also be reversible.
Conclusion. The main mechanism in the progression of MR in patients after AMI is LV myocardial dysfunction with further LV remodeling accompanied by dilatation and spherification of its cavity. The presence
of a viable myocardium in the zone of dysfunction can prevent the progression of MR, and even lead to
a decrease in its degree with adequate revascularization. Patients with MR, with a lack of viability in the
area of myocardial dysfunction, are candidates for the development of severe MI.