Afterload-related reference values for myocardial work indices

Abstract

Background The novel noninvasive pressure-strain loop (PSL) is a reliable tool that reflects myocardial work (MW). Systolic blood pressure (SBP) is the only independent factor for MW indices. However, afterload-related reference values have not been previously reported. The aim of the present study was to establish reference values for MW parameters by wide range SBP grading. Methods We prospectively selected healthy individuals and subjects with SBP ≥ 140 mmHg at the time of study without myocardial remodeling. MW parameters were collected and the reference values achieved were grouped by SBP in 10-mmHg. Results Significant differences were noted among the SBP-groups for global work index (GWI) and global constructive work (GCW). The majority of statistical comparisons of the differences in GWI and GCW were significant at each SBP-group. With SBP ranging from 90 to 189 mmHg, the parameters GWI and GCW tended to increase linearly with afterload. Overall, the global wasted work (GWW) tended to rise as SBP was increased, but not all of the differences noted in GWW were significant for each SBP-group. Global work efficiency (GWE) remained stable across all SBP-groups, with the exception of a slight drop noted when it exceeded 160 mmHg. Conclusions The amount of MW but not the work efficiency varied greatly according to the different afterload. This finding cannot be ignored during clinical research or diagnosis and afterload-related reference values are required to make a reasonable judgment on the myocardial function.

Left ventricular pressure strain loops for evaluation on myocardial work in type 2 diabetic patients with or without hypertension

“…Li et al [20] demonstrated that with the increase of SBP, GWI and GCW increased signi cantly, GWW slowly increased, and GWE remained mostly unchanged, only slightly decreased when SBP exceeded 160mmHg. During the hypertensive compensation period, the increase of afterload may lead to a transient decrease of left ventricular stroke volume, and the left ventricular myocardium can maintain the left ventricular contractility by improving myocardial metabolism (increasing GWI and GCW).…”

Evaluating Impact of Pulse Pressure on Indexes of Myocardial Work by Speckle-Tracking Echocardiography in Normotensive, Prehypertensive and Newly Diagnosed Hypertensive Patients

“…The GWE is calculated as the ratio of CW/(CW+WW). 21 All these data were calculated automatically using commercially available Echopac software for assessment, and the methodology for the MWIs was validated in previous publications.

Figure 2 Measurement of MWIs derived from LV pressure and strain by echocardiography.

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Echocardiographic Myocardial Work: A Novel Method to Assess Left Ventricular Function in Patients with Coronary Artery Disease and Diabetes Mellitus

“…GLS is reduced in the areas of the myocardium affected by ischemia, but an increase in afterload was also demonstrated to be associated with a reduction in LV longitudinal strain. In consequence, in patients with increased afterload conditions (e.g., hypertension), the evaluation of strain may lead to false interpretations of ischemia [22]. Taking afterload into account, MW may be superior to GLS in detecting the myocardial dysfunction caused by CAD.…”