Left ventricular noncompaction (LVNC) involving mainly or exclusively the right ventricle, also known as right ventricular noncompaction (RVNC) is a rare cardiomyopathy in which the noncompaction myocardium of the right ventricle can be concomitant with that of the left ventricle, or present in the right ventricle as a unique anatomic area [1]. LVNC is a cardiomyopathy marked by controversies and unresolved questions. The lack of a universally accepted definition, the overlap with other cardiomyopathies, the genetic complexity, uncertain prognostic factors, and varying management strategies all contribute to the ongoing debates surrounding LVNC. Little is known about RVNC, which is surrounded by considerable gaps in its understanding.

RVNC, akin to its left ventricular counterpart, presents a distinct and uncommon congenital disorder characterized by impaired myocardial compaction during embryonic development. The result is a prominent trabeculated appearance of the right ventricular myocardium, a cardiomyopathy infrequently observed and rarely documented in literature, mainly as case reports [2], [3], [4], [5], [6], [7], [8], [9], [10] Ventricular noncompaction is a rare form of congenital cardiomyopathy characterized by an arrest in the normal process of prenatal myocardial compaction, resulting in a spongy appearance of the myocardium, particularly the left ventricle [11,12] . Currently, even the classification of (LVNC) remains controversial as it has been classified into the group of genetic cardiomyopathy by the American Heart Association (AHA) [13] and into the group of unclassified cardiomyopathies by the European Society of Cardiology (ESC) [14]. Arbustini et al [1] questioned whether LVNC is a distinct cardiomyopathy rather than a morphologic trait that can be observed in healthy subjects with normal left ventricular size and function, and can be shared by different cardiomyopathies.

The LVNC prevalence in the general population seems to be 0.014–1.3% [11], but its true prevalence remains hard to define. The prevalence of RVNC is unknown. RVNC has been reported mostly in adults [[4], [5], [6], [7], [8],15], rarely in children [3] and newborns [9,16], but its detection in fetuses [2,10] is exceedingly rare, making it a challenging diagnostic entity to encounter. Clinically, RVNC can present with heart failure [3,15], pulmonary embolism [4,6], pulmonary hypertension [3], ventricular tachycardia [4], right bundle block [4], and sudden cardiac death [7]. RVNC has been associated with hypoplastic left heart syndrome [9], atrial and ventricular septal defects [7], tetralogy of Fallot [7], Williams syndrome [17], and pulmonary artery sling [10,18,19]. Currently, there are no literature reports of intrapartum unexpected death from RVNC.

We report the case of a female fetus with a gestational age of 41+4 weeks who came to our attention for intrapartum sudden unexpected death, resulting in stillbirth. The post-mortem investigations disclosed the presence of LVNC affecting mainly the right ventricle accompanied by cardiac conduction system and brainstem anomalies.