Echocardiographic Hypertrabeculated/Non-compacted Right Ventricle Accompanied by Atrial Septal Defect and Anomalous Pulmonary Vein Connection

Abstract

Myocardial noncompaction (NC) is a disorder of the embryonic endomyocardial morphogenesis frequently associated with congenital cardiac abnormalities. NC predominantly affects the left ventricle (LV). Right ventricle (RV) NC may occur in association with LV involvement or in isolation. A 47-year-old woman was admitted for atrial septal defect closure. Transthoracic echocardiography revealed hypertrabeculation of the RV apex, consisting of multiple deep recesses with the entrance of blood flow in color Doppler imaging, suggestive of isolated RV hypertrabeculation/NC. The RV and right atrium (RA) were enlarged, and systolic pulmonary arterial pressure was slightly increased. Our patient's associated abnormalities were atrial septal defect (superior sinus venosus type), anomalous connection of the right upper pulmonary vein to the junction of the superior vena cava and the RA, and large patent foramen ovale. Association between atrial septal defect and partial anomalous pulmonary vein connection and isolated hypertrabeculated/noncompacted RV should be considered by cardiologists.

INTRODUCTION

Myocardial noncompaction (NC) is commonly believed to be due to an arrest in ventricular trabecular compaction of the developing myocardium.[1] The left ventricle (LV) is affected in 62% of the patients and both ventricles are affected in 38% of the patients. Isolated right ventricular (RV) NC is a rare disease.[2] Echocardiography is one of the available methods for the detection of NC ventricle. Echocardiographic findings in NC include ventricular wall hypertrabeculation with deep intertrabecular recesses perfused from the ventricular cavity (as shown by color Doppler).[3]

We present a case of RV hypertrabeculation/NC associated with atrial septal defect (sinus venosus type) and partial anomalous pulmonary vein connection.

CASE REPORT

A 47-year-old woman presented with dyspnea on exertion (New York Heart Association (NYHA) functional class II), positive family history of coronary artery disease, and history of cigarette smoking, diabetes mellitus, and hypothyroidism. Physical examinations showed systolic murmur at the left upper sternal border with a fixed splitting of the second heart sound. Electrocardiography showed right axis deviation and right bundle branch block with secondary ST-T changes. Chest X-ray illustrated cardiomegaly and prominent pulmonary vasculature. Transthoracic and transesophageal echocardiographic findings comprised mild LV systolic dysfunction (ejection fraction = 45%), systolic paradoxical septal motion due to RV volume overload, significant RV enlargement with mild systolic dysfunction (RV fractional area change: 30% and RV systolic motion: 9 cm/s). Moreover, we observed RV apex hypertrabeculation with multiple intertrabecular deep recesses perfused from the RV cavity on color Doppler, suggestive of hypertrabeculation/NC [Figure 1 and Videos 1–3]. Right atrium (RA) enlargement, large atrial septal defect (26 mm, superior sinus venous type) with partial anomalous connection of the right upper pulmonary vein to the junction of the superior vena cava and the RA[Figure 2] and large patent foramen ovale were also found. Finally, there was mild tricuspid regurgitation with a peak gradient of 32 mmHg and an estimated systolic pulmonary artery pressure of 35 mmHg. Coronary angiography demonstrated patent left and right coronary arteries, and hemodynamic study showed a mildly increased systolic pulmonary artery pressure (31/9 mmHg) and RV systolic pressure (36/5 mmHg) with a pulmonary-to-systemic flow ratio of 3.5. Surgical repair of the atrial septal defect with a pericardial patch, closure of the patent foramen ovale, and redirection of the right upper pulmonary vein to the RA was done. The patient had an uneventful recovery period. Follow-up transthoracic echocardiography before discharge revealed a slightly decreased RV size, moderate RV systolic dysfunction, and an estimated systolic pulmonary artery pressure of 25 mmHg.

Figure 1.

Transthoracic imaging. Hypertrabeculation of the right ventricular apex, consisting of multiple deep recesses (upper and lower images) with the entrance of the blood flow in color Doppler imaging (middle image), suggestive of right ventricular noncompaction. LA = Left atrium, LV = left ventricle, RA = right atrium, RV = right ventricle

Figure 2.

Transesophageal imaging. Large atrial septal defect (superior sinus venosus type) with partial anomalous connection of the right upper pulmonary vein to the junction of the superior vena cava and the right atrium. AO = Ascending aorta, ASD = atrial septal defect, RPA = right pulmonary artery, RUPV = right upper pulmonary vein, SVC = superior vena cava

DISCUSSION

NC is an unclassified cardiomyopathy characterized by increased trabeculation in one or more segments of the ventricles; it is believed to be the consequence of an incomplete compaction of ventricular myocardium during intrauterine development,[4] resulting in excessive multiple trabeculations of the ventricular wall.[5] RV NC can exist in combination with LV NC[6] or in isolation.[7] The association between RV NC and atrial septal defect has been previously reported;[8] however, the present study presents the first case of an association with atrial septal defect (sinus venosus type) and partial anomalous connection of the right upper pulmonary vein.

Several criteria have been proposed for the diagnosis of LVNC. The diagnostic criteriaused by Jenni et al.,[3] included a bilayered myocardium consisting of a thin compacted layer (C) and a much thicker NC layer with deep endomyocardial recesses: NC/C > 2 measured at end-systole (acquisition = apical short-axis view with measurement of the NC/C ratio performed at end-systole). Chin et al.,[5] defined LVNC as a ratio of C/(NC + C) <0.5 at end-diastole (acquisition = LV apex using the parasternal short-axis and apical views and the LV free wall thickness at end-diastole).

Stöllberger and Finsterer[9] defined LV NC as trabeculation (four or more) protruding from the LV wall, located apically to the papillary muscles and visible in one imaging plane. The current literature lacks a definition of RVNC; nonetheless, some authors have proposed the application of the LVNC criteria for the definition of RVNC.[10]

RVNC is a very rare entity, and since the RV apex is intensely trabeculated, it is difficult to differentiate between normal and pathologic patterns. Echocardiography is the first-line diagnostic tool. Additional imaging techniques such as cardiac magnetic resonance imaging (MRI) (which was refused by our patient) may be helpful. Clinical presentation and prognosis can vary from mild to severe heart failure, occurrence of ventricular tachycardia, cardioembolic events, syncope, and even sudden cardiac death.[2]

In our patient, there was a possibility of acquired hypertrabeculation (due to prolonged volume over load), but heavy trabeculation in the RV apex is not usual in atrial septal defect. The association between RVNC and atrial septal defect may be explained by demand ischemia and neuroendocrine activation.[8] Preoperative RV dysfunction in this case can be due to volume overload or in association with NC.[7,8]

This case report presents a rare, albeit possible, association between atrial septal defect and partial anomalous pulmonary vein connection and isolated RV NC. It, therefore, seems advisable that cardiologists and echocardiologists pay heed to the possibility of right NC myocardium.