CONGRESS ABSTRACT

Case report: A 62-year-old man, history of hypertension. In 2015, there was suspicion of non-compaction cardiomyopathy, and he underwent cardiac MRI at another facility (report not available). The patient reported palpitations and dyspnea with exertion, leading to a follow-up visit. EKG showed sinus rhythm 90/min, nonspecific intraventricular conduction delay and isolated monomorphic ventricular ectopic beats. Echo revealed a mildly dilated left ventricle (end-diastolic volume 88 ml/m), systolic function at the lower limits of normal (EF 53%), and prominent muscular structures near the posterior interventricular septum (SIV), likely related to anomalies of the papillary muscles (prominent and possibly duplicated posterior-medial papillary muscle). There was apical trabecular protrusion, which did not meet the criteria for non-compaction (NC/C ratio in systole approximately 1), with no other significant findings. The cardiac MRI, performed to assess dilated cardiomyopathy, revealed a conspicuous structural abnormality in the septo-papillary region, located medio-apically and paraseptal-endocardial in the left ventricle. This anomaly lacked evident chordae tendineae with the mitral valve leaflets and exhibited synchronous systo-diastolic motion with the left ventricular wall, suggesting septal duplication. The septal thickness was slightly reduced, particularly in the medio-apical region. Additionally, there was hypertrabeculation of the posterior and lateral walls of the left ventricle, exceeding the threshold for non-compaction (NC/C ratio in end-diastole: 2.6 – normal range: <2.3). Left ventricular mass was normal (mass: 173.52 g; mass/body surface area (BSA): 86.58 g/m). Basal septum, medio-apical septum and medio-apical lateral wallshowed hypokinetic contractility. The left ventricle was dilated (end-diastolic diameter: 55.0 mm; end-systolic diameter: 45.3 mm - end-diastolic volume: 230 ml; stroke volume/BSA: 57.6 ml/m² - EF: 51%). Areas of late gadolinium enhancement (LGE) were observed in the anterior medio-basal septum and at the site of the described structural muscular anomaly, both displaying an intramural non-ischemic pattern. Conclusions: The described findings suggest a picture of dilated cardiomyopathy and an associated structural septo-papillary anomaly of uncertain diagnostic interpretation (septum duplication with associated non-compacted myocardium? duplicated posterior-medial papillary muscle with associated non-compacted myocardium?).