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[Analysis of left ventricular blood flow in cases of myocardial infarction: a preliminary report]
Insights
Two-dimensional Doppler echocardiography revealed abnormal left ventricular blood flow patterns in myocardial infarction patients. These unique high-velocity flows during specific cardiac phases suggest impaired wall contractions and potential eddy currents.
Area of Science:
- Cardiology
- Medical Imaging
- Fluid Dynamics
Context:
- Myocardial infarction (MI) significantly impacts left ventricular (LV) function.
- Assessing LV blood flow dynamics is crucial for understanding MI pathophysiology.
- Two-dimensional Doppler echocardiography offers a non-invasive method to visualize intracardiac flow patterns.
Purpose:
- To analyze and characterize left ventricular blood flow patterns in patients with myocardial infarction using two-dimensional Doppler echocardiography.
- To differentiate abnormal flow dynamics in MI patients from healthy controls.
- To investigate the relationship between abnormal flows and myocardial asynergy or ventricular aneurysm.
Summary:
- Doppler recordings were obtained from nine LV areas in 25 MI patients (with/without aneurysm) and 15 controls.
- Healthy subjects exhibited normal systolic ejection flow and diastolic inflow patterns.
- MI patients showed abnormal high-velocity flows during isometric relaxation (away from asynergic areas) and systole (towards apex), not seen in controls.
Impact:
- Identifies novel Doppler echocardiographic findings indicative of myocardial infarction.
- Suggests that continued diastolic mitral inflow inertia during systole contributes to observed abnormal flows in MI.
- Provides insights into the mechanical consequences of impaired myocardial contraction on intracardiac hemodynamics.
Abstract:
Analysis of left ventricular blood flow in cases of myocardial infarction was attempted by two-dimensional Doppler echocardiography. Subjects consisted of 25 cases of myocardial infarction with and without ventricular aneurysm, and 15 healthy persons as controls. The Doppler recordings were made in nine areas within the left ventricular cavity from the apical approach. For healthy subjects, ejection flows were recorded in the main cavity and directed towards the aortic orifice in systole, and diastolic flows in the left ventricular inflow were recorded from the mitral orifice to the apex. However, diastolic flows toward the aortic orifice were also recorded along the interventricular septum, and interpreted as eddy currents from the apical cavity. There were no high velocity flows in the phases of isometric contraction and relaxation. In seven of 25 cases of myocardial infarction, abnormally high velocity flows of more than 30 cm/sec were recorded in the isometric relaxation phase, which were directed away from the asynergic part. In eight of the 25 patients examined, high velocity flows toward the cardiac apex were recorded at the posteroapical area in systole. Such flows have never been observed in healthy subjects. Inertia of the diastolic mitral inflow is considered to continue during systole due to impairment of contractions of the apicoinferior wall.