Assessment of papillary muscle function in patients with inferior wall myocardial infarction using Doppler tissue imaging

Objectives: We sought to assess the relationship between infarct status and systolic contractile function of papillary muscle (PM) for patients with inferior wall myocardial infarction (MI). Methods: Peak systolic velocity (V) of posteromedial PM, systolic strain (ε) of posteromedial PM (ε_PM), V of adjacent inferior wall, and ε of adjacent inferior wall (ε_W) were calculated from color Doppler tissue imaging images obtained at apical views in 25 patients with inferior MI and in 13 healthy control subjects. All 25 patients with MI underwent magnetic resonance imaging to assess the infarct status of PM. Results: Compared with the control subjects, patients with MI had significantly lower V of adjacent inferior wall (5.0 ± 0.8 vs 4.4 ± 1.1 cm/s, P = .049) and V of posteromedial PM (4.9 ± 0.8 vs 4.0 ± 1.2 cm/s, P = .005), and less systolic deformation, as demonstrated by ε_W (-17 ± 3 vs -6 ± 5%, P < .001) and ε_PM (-24 ± 5 vs -11 ± 6%, P < .001). There was a weak positive correlation between ε_W and ε_PM (r = 0.393, P = .052) for patients with MI. Magnetic resonance imaging showed total infarct of PM in 14 patients (group A), with the remaining 11 revealing either normal perfusion or partial infarct of PM (group B). Although ε_W was similar in groups A and B (-5 ± 5% vs -8 ± 6%, P = .20), ε_PM was significantly lower in group B (-7 ± 4% vs -16 ± 4%, P = .004). Conclusions: In patients with inferior wall MI, infarct status of the PM is variable and determines its systolic contractile function, which can be quantified by ε measurement using Doppler tissue imaging.