Impact of papillary muscle infarction on atrial and ventricular myocardial deformation in non-anterior STEMI patients

The purpose of this study was to explore the impact of papillary muscle (PPM) infarction on left atrial and ventricular strain parameters in patients with non-anterior ST-segment elevation myocardial infarction (NA-STEMI) using cardiovascular magnetic resonance (CMR). This retrospective study performed CMR scans on 88 consecutive patients with NA-STEMI (68 males, 65 ± 10.05 years). Among them, 30 demonstrated PPM infarction (25 males, 67.12 ± 9.49 years), defined as late gadolinium enhancement (LGE) in a papillary muscle head in two contiguous LGE CMR slices, and confirmed on the long-axis LGE CMR slices. Atrial and ventricular strain were analyzed by CMR feature tracking with dedicated post-processing software. Patients with PPM infarction were older (p = 0.001), with lower left ventricular ejection fraction (p = 0.040), higher indexed left ventricular end-diastolic volume (p = 0.020), and end-systolic volume (p = 0.044) compared to patients without LGE in the papillary muscle. Additionally, patients with PPM infarction showed impaired reservoir strain, booster strain, global longitudinal strain (GLS), and higher LGE extent compared to NA-STEMI patients without PPM involvement (p = 0.001, p = 0.004, p = 0.001, and p = 0.003, respectively). In multivariable analysis, GLS, global radial strain, reservoir strain, and booster strain parameters were the only independent determinants of PPM infarction (p = 0.001, p = 0.041, p = 0.002, and p = 0.027, respectively). The presence of PPM infarction assessed by CMR is independently linked to atrial and ventricular strain impairment in patients with NA-STEMI.