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[Blood flow patterns in the left ventricle in patients with myocardial infarction and ventricular aneurysm:
A Konishiike1, S Mihata, Y Matsumori
1First Department of Internal Medicine, Hyogo College of Medicine.
Insights
Real-time 2-D Doppler echocardiography reveals altered intraventricular blood flow patterns in patients with myocardial infarction. These patterns correlate with left ventricular aneurysm size and ventricular dysfunction, aiding in severity assessment.
Area of Science:
- Cardiology
- Medical Imaging
- Fluid Dynamics
Context:
- Left ventricular aneurysms and dysfunction significantly impact intraventricular blood flow dynamics.
- Assessing these hemodynamic changes is crucial for understanding myocardial infarction severity.
- Traditional methods may not fully capture the complex flow patterns within the left ventricle.
Purpose:
- To evaluate the effect of left ventricular aneurysm size and ventricular dysfunction on intraventricular blood flow.
- To classify systolic left ventricular blood flow patterns using real-time 2-D Doppler echocardiography.
- To correlate these flow patterns with myocardial infarction severity and left ventricular function.
Summary:
- Systolic left ventricular blood flow patterns were analyzed in 42 myocardial infarction patients and 10 controls using real-time 2-D Doppler echo.
- Patients were grouped based on inflow patterns: early systole (Group I), mid-systole (Group II), and end-systole (Group III).
- Ejection fraction (EF) decreased significantly across groups (53% in I, 41% in II, 29% in III), while left ventricular dimensions and non-contractile circumference increased, indicating worsening dysfunction from Group I to III.
Impact:
- Real-time 2-D Doppler echocardiography provides valuable insights into intracardiac blood flow.
- The study demonstrates a clear correlation between altered blood flow patterns and the severity of myocardial infarction.
- This technique aids in evaluating the extent of myocardial damage and associated ventricular dysfunction.
Abstract:
To evaluate how the intraventricular blood flow is affected by the size of a left ventricular aneurysm and ventricular dysfunction, systolic left ventricular blood flow patterns were evaluated using two-dimensional Doppler flow images (real-time 2-D Doppler echo). The subjects consisted of 10 normal controls, 35 patients with anteroseptal infarction, two patients with inferior infarction and five patients with anteroseptal-inferior infarctions. The systolic period was divided into three subsets; early, mid- and end-systole. Forty-two patients with myocardial infarction were classified into three groups according to the left ventricular inflow patterns on real-time 2-D Doppler echo using the apical left ventricular long-axis approach; i.e., inflow signals confined to early systole (Group I), visualized up to mid-systole (Group II) and end-systole (Group III). Left ventricular end-diastolic dimension (LVDd), left ventricular end-systolic dimension (LVDs), and % non-contractile circumference (delta L) were calculated by the same echocardiographic approach. Ejection fraction (EF) was calculated by left ventricular cineangiography using the Simpson's method. The left ventricular inflow Doppler signals in the normal controls and Group I turned in the apex and then directed toward the left ventricular outflow tract during late diastole and early systole. Significant differences in EF were observed among the three groups. EF in Group I, II and III was 53 +/- 9%, 41 +/- 8% and 29 +/- 7%, respectively. However, LVDd, LVDs and delta L had the largest values in Group III and the smallest values in Group I. LVDd, LVDs and delta L were smallest in Group I and largest in Group III. In the normal controls, the left ventricular inflow signals proceeded to the apex and directed toward the left ventricular outflow tract in the early systolic period. Various changes in the inflow pattern were observed in patients with myocardial infarction and severe wall motion abnormalities, including delayed timing in proceeding from the apex to the left ventricular outflow tract, stagnant blood at the apex and further inflow of blood toward the apex even during end-systole. The patients with sustained inflow during late systole had hypofunction of the left ventricle as demonstrated by smaller EF and larger LVDd, LVDs, and delta L. In conclusion, the observation of intracardiac blood flows by real-time 2-D Doppler echo is of help in evaluating the severity of myocardial infarction.