抄録
Background. Previously, there was no standard technique for accurately measuring papillary muscle (PM) function. The aim of the present study was to investigate PM contractility using myocardial strain imaging in patients with myocardial infarction.
Methods. We recorded motion velocities using tissue velocity imaging and strains using myocardial strain imaging at the mid-portion of the posteromedial PM and at the mid-portion of the left ventricular (LV) inferior/posterior wall on the apical 2-chamber view in 29 patients. The patients were divided into 2 groups: a normal control (C) group (n=21; mean LV ejection fraction, 77±11%) and an inferior/posterior myocardial infarction (MI) group (n=8; mean LV ejection fraction, 59±17%).
Results. There was no difference in mean age between the 2 groups (C; 55±16 years, MI; 65±11 years). The peak systolic velocities of the LV inferior/posterior wall were significantly lower in the MI group than in the C group (C; 9.1±3.0 cm/s, MI; 6.1±2.2 cm/s, p<0.05), whereas there was no difference in the peak velocities of the posteromedial PM between the 2 groups (C; 6.3±1.3 cm/s, MI; 5.3±1.0 cm/s). In contrast, the peak systolic strains in the MI group were significantly lower in both the LV inferior/posterior wall (C; -27±5%, MI; -16±5%, p<0.01) and the posteromedial PM (C; -26±5%, MI; -16±4%, p<0.01).
Conclusions. These results suggest that myocardial strain imaging is more sensitive and accurate for determining PM contractility compared to tissue velocity imaging.
