Echocardiography

Myocardial strain (⑀) is a dimensionless index of change in myocardial length in response to an applied force. ⑀ Rate (SR) is the rate of change of length and is usually obtained as the time derivative of the ⑀ signal. In echocardiography, SR is calculated as the difference between 2 velocities normalized to the distance between the 2 velocities. SR imaging (SRI) has a theoretic advantage over Doppler tissue imaging in that SRI is relatively immune to cardiac translational motion and tethering. Therefore, SRI may be superior to Doppler tissue imaging in quantitative assessment of regional myocardial function and may find clinical application in the interrogation of coronary artery disease. The high frame rates of SRI have also renewed interest in timings of global and regional mechanical events, and their potential clinical applications. The high temporal resolution allows SRI to depict regional systolic and diastolic asynchrony. Ongoing clinical trials will determine the sensitivity, specificity, and accuracy of SRI parameters for a variety of clinical conditions. Potential clinical applications include investigation of ischemia (at rest and with stress), myocardial viability, and altered global and regional systolic and diastolic function in cardiomyopathies. Suboptimal signal quality remains a major limitation of strain imaging, and advances in data acquisition and postprocessing capabilities will help determine its future incorporation into standard regional myocardial assessment. (J Am Soc Echocardiogr 2003;16:1334-42.) Mirsky and Parmley, 1 first introduced the concept of strain (⑀) and strain rate (SR) as measures of myocardial mechanical properties. Myocardial strain is a dimensionless index of change in myocardial length in response to an applied force and is expressed as fractional or percent change . SR is the time derivative of strain with unit of per second (s Ϫ1 ) and in ultrasound represents the differential velocity of 2 points normalized for the distance between them ). By convention, myocardial lengthening or thinning gives a positive strain value and shortening or thickening gives a negative value. For 1-dimensional strain ⑀ ϭ ⌬L L 0 and corresponding SR

Background: Myocardial infarction is a public health problem. Functional food is an alternative treatment for cardiovascular diseases. Objective: The objective was to analyze the functional and anatomopathological post-myocardial-infarction effects of soybean extract (SE) and isoflavone (IF). Methods: Myocardial infarction was induced in adult Wistar rats. After 5 days, an echocardiogram was performed to determine heart rate (HR), ejection fraction (EF), systolic volume (LVESV) and diastolic volume (LVEDV). Animals with ventricular dysfunction (EFb45%) were selected for study. The animals were divided into three groups: control (n=14), SE (n=15) and IF (n=12). The IF group received 120 mg/kg/day isolated IF, and the SE group received 12.52 g/day. After 30 days, a new echocardiogram was performed. A histological exam was carried out to determine the collagen. Activity of biochemical markers [arginase, lactate dehydrogenase (LDH) and malate dehydrogenase] was measured. Results: The animals of the control, IF and SE groups showed a reduction in EF after the infarction (P=.432, P=.017 and P=.320, respectively). An increase of LVESV and LVEDV was observed in all groups (P=.009, P=.001 and P=.140; and P=.003, P=.008 and P=.205, respectively). A reduction of HR was found in the SE group (P=.020). There was a greater activity of LDH in the SE group. A smaller quantity of mature collagen was found in the region proximal to the myocardial infarction in the SE group. Conclusion: A protective effect in the SE group was observed 30 days after the myocardial infarction.