From cold-blooded reptiles to embryological remnants: Persistent myocardial sinusoids

Abstract

In nature, basically 2 types of myocardial vascular patterns exist: the sinusoidal and the coronary type. In the sinusoidal type, the sinusoid is completely fed by blood coming directly from the ventricle through a spongy sinusoidal network. This pattern is found in cold-blooded animals and in the early embryologic development of human (warm-blooded) hearts. A 61-year-old man with atrial fibrillation developed severe tachymyopathy with a severely reduced left-ventricular ejection fraction (LVEF) of 20%. The patient had no history of prior heart surgery or other cardiac interventions. He was referred for a computed tomography (CT) scan for assessment of pulmonary vein anatomy prior to their isolation. Incidentally, a focal myocardial defect of the midventricular infero-septal wall with tail-like extension into the right ventricular cavity was detected. In a cardiac magnetic resonance (CMR) scan there was no evidence of a myocardial infarction or fibrosis. In the absence of a ventricular septal defect by CT, CMR and echocardiography the diagnosis of a persistent myocardial sinusoid was evident. In this case, we used state-of-the art methods for pathology visualization, illustrating the effectiveness of CT and CMR in the precise detection and differential diagnosis of myocardial anomalies including a multi-coloured 3D-printed model that may further enhance visuospatial appreciation of those anomalies.

Keywords: CABG, coronary artery bypass surgery; CMR, cardiac magnetic resonance; CT, computed tomography; Coronary vessels; Heart Septal Defects, Ventricular; LVEF, left-ventricular ejection fraction; Magnetic Resonance Imaging; Myocardium; Printing, Three-Dimensional; TMLR, transmyocardial laser revascularization therapy; Tomography, X-Ray Computed.

Fig. 1

Contrast-enhanced computer tomography (CECT) image demonstrating the contrast-material filled defect in the left-ventricular, midventricular infero-septal wall with tail-like extension into the myocardium

Fig. 2

Image of an in-house 3D-printed model of the patient's heart with isolation of the left-sided heart. The myocardial sinusoid has been painted in dark red for better visualization

Fig. 3

Images from a cardiovascular magnetic resonance examination of the patient. Upper row (from left to right): Late gadolinium enhancement (LGE) images demonstrating the absence of myocardial infarction. Lower row (from left to right): T1 map on the level of the myocardial sinusoid demonstrating blood-pool equivalent signal in the midventricular infero-septal wall. 4-chamber CINE image without evidence of a ventricular septum defect (VSD) on the level of the myocardial sinusoid. Stress perfusion image demonstrating again the presence of the myocardial sinusoid as a blood-filled structure that extends beyond the endocardium of midventricular septum (see also Video 3)

Fig. 4

From: Vineberg A. Coronary vascular anastomoses by internal mammary artery implantation. Can Med Assoc J 1958;78:871-9. According to Canadian Medical Association Journal's requirements, no reprint permission is necessary for using unmodified figures