Incidence and characteristics of segmental postsystolic longitudinal shortening in normal, acutely ischemic, and scarred myocardium.

Objective: Myocardial longitudinal shortening after aortic valve closure (postsystolic shortening [PSS]) is considered a marker of pathology with diagnostic potential. However, PSS can also occur in healthy subjects. We, therefore, investigated the occurrence and characteristics of PSS in control subjects and patients, and how to distinguish normality from disease.

Methods: In 20 young control subjects, 10 older control subjects, 30 patients with acute myocardial infarction (acute ischemia), and 10 patients with postischemic myocardial scar, longitudinal myocardial deformation was measured with Doppler tissue strain rate (SR) imaging. Segmental SR and strain were visually and quantitatively analyzed and compared.

Results: In young control subjects, PSS was found in 98 of 313 segments (31%) and showed gaussian distribution (median 1.3%). During ejection time, median peak SR was -1.4 s(-1) and median strain -16.6%. In older control subjects, parameters differed only slightly. In acutely ischemic and scarred myocardium, both systolic strain and SR were significantly reduced or inverted. In disease, PSS occurred significantly more often (78% and 79%, respectively), was significantly higher in magnitude, and its peak occurred later than in young and older control subjects.

Conclusion: PSS is a normal finding in healthy subjects occurring in approximately one-third of myocardial segments and, thus, is not always a marker of disease. Our data indicate that pathologic PSS can be detected by coexisting reduction in systolic strain and, second, by exceeding a postsystolic strain magnitude cutoff.