In a number of patients with EF 60% or more, signs of heart failure are clinically detected. As a rule, such a condition is caused by LV diastolic dysfunction (impaired relaxation processes due to ischemia, cardiosclerosis, hypertrophy of the walls, pericardial effusion, etc.). According to a number of researchers, patients with signs of heart failure caused only by diastolic dysfunction constitute 15–25% of all patients with HF.
Diastolic dysfunction of the LV is estimated according to the results of a study of transmitral diastolic blood flow in a pulsed mode. Determine: 1. the maximum speed of the early peak of the diastolic filling M1, 2. the maximum speed in the atrial systole M2, 3. the integral of speed (area under the curve) of the early diastolic filling (VTI E), 4. the integral of the speed of atrial systole (VTI A), 5 LV isovolumetric relaxation time (IVRT), 6. time to slow the early diastolic filling (DT).
In the early stages of LV diastolic dysfunction with a slight increase in the end-diastolic pressure in the LV cavity, a decrease in the time of isovolumetric relaxation is observed and blood flow increases during the atrial systole (M1 and VTI E values decrease, while M2 and VTI A increase), which is a rigid type of filling. This indicates that most of the diastolic filling of the LV occurs in the atrial systole. Further deterioration of diastolic compliance of the left ventricle leads to a significant increase in end-diastolic pressure in it (respectively in the left atrium) and “pseudonormalization” of transmitral blood flow – a restrictive type of filling.
Evaluation of impaired regional contractility 1
To assess the regional contractility of the LV, the B-mode cardiac imaging along the long and short axes with LV division into segments reflecting the preferential blood supply from the corresponding branches of the coronary arteries is used.
The division of the LV into segments and their correspondence to the branches of the coronary arteries (according to Edwards)
In each of these segments, the nature and amplitude of myocardial movement is assessed. There are 3 types of local disorders of the contractile function of the left ventricle, united by the concept of “asinergy”: hypokinesia – pronounced local reduction in the degree of contraction, akinesia – the absence of contractions of the myocardium, dyskinesia – paradoxical movement (bulging) of the myocardial segment in the systole.