Arrhythmogenic mitral annular disjunction: papillary muscle abnormalities as a novel component

Mitral annular disjunction (MAD) is a relatively common condition that can be associated with ventricular arrhythmias. This study aims to assess the significance of abnormalities in the left ventricular papillary muscles, as detected by cardiac magnetic resonance imaging (MRI), and their correlation with the echocardiographic Pickelhoube sign and arrhythmogenic burden in patients with MAD.

A retrospective study was conducted involving 63 consecutive patients with MAD identified via a 1.5T MRI scanner. All patients underwent echocardiography, and 51 patients (81%) also completed a 24-hour Holter electrocardiography. The study evaluated the visual presence of the dark papillary muscle sign (dark PAP), late gadolinium enhancement in the papillary muscles (PAP LGE), and the echocardiographic Pickelhoube sign, known to be associated with a higher risk of ventricular arrhythmias. Additionally, the 24-hour Holter ECG assessed the number of premature ventricular contractions (PVCs), using a threshold of more than 1000 beats per 24 hours, and the presence of nonsustained ventricular tachycardia (nsVT).

The average MAD length in the study population was 5.29 ± 0.43 mm (95% CI). The dark PAP sign was observed in 42 patients (67%), PAP LGE in 11 patients (17%), and the echocardiographic Pickelhoube sign in 34 patients (54%). Ventricular arrythmias (nsVT and more than 1000 PVCs per 24 hours) were found in 24 patients (38%). The dark PAP sign was significantly associated with the echocardiographic Pickelhoube sign (p < 0.001). Ventricular arrhythmias (PVCs) were more frequent in patients with PAP LGE (p < 0.03). The small number of nsVT cases (6 patients) precluded statistical analysis.

The study found that the dark PAP sign correlates with the echocardiographic Pickelhoube sign, and PAP LGE is associated with a higher burden of ventricular arrhythmias. Further prospective studies in larger populations are needed to evaluate the potential of papillary muscle characteristics in risk stratification for ventricular arrhythmias in patients with MAD.

dark PAP positive