Canine infantile left ventricular noncompaction

Abstract

Background Left ventricular noncompaction (LVNC) is a rare form of cardiomyopathy currently described in humans and cats. It consists of a spongy myocardium characterized by prominent trabeculation and deep recesses involving more than 50% of the ventricular thickness. We describe the clinical and pathological features of LVNC combined with tricuspid valve dysplasia, double-orifice tricuspid valve and severe pulmonary stenosis in a puppy. In addition, we briefly review the LVNC causes, pathogenesis, forms and current diagnostic criteria. Case presentation A seven-week-old intact German Shorthaired Pointer-cross male was presented with a poor body condition, exercise intolerance and dyspnea. Clinical exam identified a bilateral systolic murmur (grade IV/VI over the right heart base and grade III/VI over the left heart base). Echocardiography identified tricuspid valve dysplasia, mild mitral regurgitation, and severe pulmonic stenosis with a trans-valvar systolic pressure gradient of 106 mmHg. Left ventricular noncompaction was diagnosed by necropsy and further confirmed histopathologically by the presence of two distinct myocardial layers: an inner noncompacted zone covering more than 50% of ventricular thickness containing prominent trabeculation and deep recesses, and an outer zone of compact myocardium. Conclusions This is the first case describing LVNC in a canine patient, supporting the introduction of this form of heart disease as a differential diagnosis for cardiomyopathies in juvenile and adult dogs.

Trabeculations of the porcine and human cardiac ventricles are different in number but similar in total volume

“…The notion of compaction as an important developmental process gained attention when it was hypothesized that its absence, so‐called noncompaction, leads to a setting of excessive trabeculation and cardiomyopathy (Chin et al, 1990; Finsterer et al, 2017; Jenni et al, 2001; Kittleson et al, 2017; Oechslin et al, 2000; Vilcu et al, 2020). That noncompaction results in a greater‐than‐normal number of trabeculations in the fetus or adult, can be inferred from the following quotations: the “stratum spongiosum of each ventricle underwent differentiation but failed to resorb” (Van Praagh et al, 1964); the “gross anatomical appearance is characterized by numerous, excessively prominent trabeculations” (Chin et al, 1990); “altered structure of the myocardial wall as a result of intrauterine arrest of compaction of the myocardial fibers” (Oechslin et al, 2000).…”

Trabeculations of the porcine and human cardiac ventricles are different in number but similar in total volume

“…The notion of compaction as an important developmental process gained attention when it was hypothesized that its absence, so-called noncompaction, leads to a setting of excessive trabeculation and cardiomyopathy [24][25][26][27][28][29]. That noncompaction results in a greater-than-normal number of trabeculations in the fetus or adult, can be inferred from the following quotations: the "stratum spongiosum of each ventricle underwent differentiation but failed to resorb" [30]; the "gross anatomical appearance is characterized by numerous, excessively prominent trabeculations" [24]; and "altered structure of the myocardial wall as a result of intrauterine arrest of compaction of the myocardial fibers" [25].…”