Authors

• Ana Fabris — Poliklinika “Sv. Nikola”, Korčula, Hrvatska — ORCID: 0000-0001-9588-6788
• Mila Jakovljević — Poliklinika “Sv. Nikola”, Korčula, Hrvatska — ORCID: 0000-0002-1921-4098

Abstract

Stress echocardiography (SE) is widely used method for assessing coronary artery disease, myocardial viability and valvular heart disease. Among the various stress modalities exercise is safer than pharmacologic stress. (1) Quantitative wall motion analysis during SE may overcome deficiency of visual assessment of systolic thickening and myocardial motion i.e. estimating radial function only. Subendocardial fibers that support the longitudinal function are more sensitive to ischemia and heart failure. (2) There are different methods proposed for quantitative assessment of the left ventricular function feasible in exercise stress echocardiography and each has some drawbacks. Strain imaging techniques can be derived from the color-coded TDI (tissue Doppler imaging) or based on the 2DS (2-dimensional strain). In any Doppler-derived method, the velocities measured are angle-dependent, apical segments cannot be reliably depicted and, because of base-to- apex velocities gradient, there is a need for different segmental cut-off values. Cardiac translation and rotation limit the TDI. The 2DS is more suitable for exercise SE for it is angle-independent and can be used in any projection. 2DS enables display of apical segments and all segments of the specific coronary artery territories. In our work, we first use visual estimation – WMSI (wall-motion score index) and then the single-segment model based on the TDI with offline analysis before exercise and immediately upon peak exercise (within 1 minute) (**Figure 1**). Velocities, strain and strain-rate values are compared with cut-off values and expressed as delta >50% increase. (3) An additional analysis (AFI, automated function imaging) of segmental strain, PSS (post systolic shortening) and TTP (time-to-peak) longitudinal strain based on the 2DS as well as an estimation of the E/E’ ratio are performed before and immediately upon peak exercise (**Figure 2**). This combined approach allows more accurate estimation of ischemia and heart failure. In our experience, feasibility of the 4D exercise SE, both full volume and multiplane mode, is very low because of low spatial and temporal resolutions which become worse at a faster heart rate (FR of 40 fps). The combined approach in quantitative assessment of exercise SE that includes determination of parameters of both systolic (WMSI, TDI, 2DS) and diastolic functions (E/E’) provides a more accurate estimation of ischemia and/or heart failure. FIGURE 1. Tissue Doppler imaging analysis before and immediately after exercise: 20-year male patient with hypertrophic cardiomyopathy. FIGURE 2. Automated function imaging analysis before and immediately after exercise: 70-year female patient who has overcome myocardial infarction.

Keywords

stress echocardiography, exercise stress, quantitative assessment

DOI

Literature

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