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Early detection of diabetic patients at high risk for developing diabetic cardiomyopathy may permit effective intervention. The goal of this work is to determine whether measurements of the magnitude and time delay of cyclic variation of myocardial backscatter, individually and in combination, can be used to discriminate between subgroups of individuals including normal controls and asymptomatic type 2 diabetes subjects. Two-dimensional parasternal long-axis echocardiographic images of 104 type 2 diabetic patients and 44 normal volunteers were acquired. Cyclic variation data were produced by measuring the mean myocardial backscatter level within a region-of-interest in the posterior wall, and characterized in terms of the magnitude and normalized time delay. The cyclic variation parameters were analyzed using Bayes classification and a nonparametric estimate of the area under the receiver operating characteristic (ROC) curve to illustrate the relative effectiveness of using one or two features to segregate subgroups of individuals. The subjects were grouped based on glycated hemoglobin (HbA1c), the homeostasis model assessment for insulin resistance (HOMA-IR), and the ratio of triglyceride to high-density lipoprotein cholesterol (TG/HDL-C). Analyses comparing the cyclic variation measurements of subjects in the highest and lowest quartiles of HbA1c, HOMA-IR, and TG/HDL-C showed substantial differences in the mean magnitude and normalized time delay of cyclic variation. Results show that analyses of the cyclic variation of backscatter in young asymptomatic type 2 diabetics may be an early indicator for the development of diabetic cardiomyopathy.

During the past twenty years, there has been a dramatic increase in obesity and the cardiometabolic syndrome (CMS). In the United States alone, there are an estimated 42 million persons affected by CMS.1 In addition to complications from diabetes and hypertension, this population is at risk for the development of both ischemic and nonischemic heart failure.2 Although it is fairly well accepted that obesity and other aspects of CMS contribute to left ventricular (LV) remodeling and diastolic dysfunction, controversy does exist as to the effects of CMS on systolic function.2 This is partly due to the fact that obesity is associated with an increase in plasma volume.2 Thus, any load-dependent measures of systolic function, e.g., cardiac output, are necessarily affected by alterations in volume as well as contractility. Different methods for indexing LV systolic function measures in obese subjects may also affect systolic function results. For example, cardiac output may be increased in obesity but when indexed for body surface area, cardiac index may be low. Thus, newer, more load-independent noninvasive methods are necessary for better characterizing LV systolic function.Tissue Doppler imaging (TDI), an echocardiographic method previously described in the Images in CMS section of the Journal of the Cardiometabolic Syndrome, is considered to be relatively load-independent.3 Although, TDI is relatively easy to perform and measure, it does have some limitations. TDI provides a longitudinal assessment of the function of an entire wall rather than of a segment, so localization of the segmental wall motion abnormalities using TDI is limited.4 Additionally, because it is a Doppler-derived parameter, it is necessarily angle-dependent, and so TDI-derived measures of function are angle-dependent.A new echocardiographic technique called strain imaging, overcomes some of the limitations of TDI. Like TDI, strain imaging is thought to be relatively load-independent, but strain imaging has other advantages as well. Strain imaging allows for segmental wall motion quantification and (when quantified using speckle tracking) is not angle-dependent. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptIn order to explain this technique it is first important to define "strain" as it pertains to LV systolic function. Strain means deformation and is calculated as the change in length divided by the original length.4 As such, strain is dimensionless and typically represented as a negative fractional or percentage change in dimension. Since LV contraction in systole causes LV deformation (strain), strain is a measure of contractility.4 (The rate at which the LV deforms may also be measured echocardiographically and is termed "strain rate," but this imaging article will focus on strain). LV contraction is a three-dimensional process that involves radial and longitudinal cardiac muscle fibers. As longitudinal fibers shorten the ventricle, radial fibers squeeze in and twist in a clockwise direction at the base and counte...

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