Papillary muscle scarring may represent a concealed marker of cardiac vulnerability in patients with DCM, even in the absence of epicardial coronary artery disease, according to findings published in JAMA Cardiology.

This single-center cohort study enrolled 470 patients (mean age, 55.3 years; 43.6% female) with known or suspected DCM who underwent cardiovascular magnetic resonance imaging between 2011 and 2020 at an academic hospital in North Carolina. The imaging protocol included FIDDLE MRI, which enhances the visualization of papillary muscle scarring. Follow-up extended up to eight years, encompassing 2,082 patient-years.

Papillary muscle scarring was identified in 137 patients (29.1%) and was not associated with differences in left ventricular ejection fraction. However, it was independently associated with higher risk of cardiac death (hazard ratio [HR], 1.86; 95% CI, 1.07–3.24; P = .03), heart failure events (HR, 2.05; 95% CI, 1.16–3.61; P = .01), and arrhythmia events (HR, 3.41; 95% CI, 1.46–7.94; P = .005) after adjustment for established prognostic variables including age, systolic blood pressure, heart rate, ejection fraction, and midwall scar.

These results establish papillary muscle scarring as an independent imaging biomarker with incremental prognostic value in DCM. Incorporating FIDDLE MRI into clinical practice may improve early risk detection and guide individualized management strategies.