Case report

A male infant of Canadian First Nations ethnicity was delivered at 39 weeks gestational age as the fourth pregnancy of an 18-year-old mother, one of the pregnancies having been aborted, and the others producing two living children. No exposure to teratogens was noted in the antenatal record. The diagnosis of pulmonary atresia with intact ventricular septum with good bi-ventricular function was established at 31 weeks gestation. A repeated fetal echocardiogram at 38 weeks gestation demonstrated markedly decreased left ventricular function (Fig. 1), and prompted induction of labor. The weight at birth was 3.66 kg, with Apgar scores of 6 at 1 min, and 8 at 5 min. The pH measured in the cord blood was 7.29. The baby was admitted to the intensive care unit and commenced on prostaglandin E1, being well grown and without dysmorphic features.

Figure 1. Fetal echocardiogram. Systolic (a) and diastolic (b) still frames of left ventricular inflow and outflow. Note the lack of volume change between systole and diastole. The mitral valve (arrows) is open in the diastolic frame and closed in the late systolic frame after aortic valvar closure. LV: left ventricle; LA: left atrium; Ao: aortic root; RV: right ventricle.

Inotropic support with dopamine was required to maintain adequate blood pressure. The chest radiograph confirmed the usual arrangement of the contents of the thorax and abdomen with reduced vascular markings.

The electrocardiogram showed normal sinus rhythm, normal QRS axis, normal intervals, left atrial enlargement, left ventricular hypertrophy, a paucity of right ventricular forces, and non-specific ST-T changes. There were no pathological “Q” waves to indicate myocardial infarction.

A post natal echocardiogram confirmed the usual arrangements and normal connections, with pulmonary atresia and intact ventricular septum. The right atrium was large with an unrestrictive atrial communication. The right ventricle was diminutive, with the tricuspid valve being of no more than 3 mm in diameter, corresponding to a Z score of more than −3, with the valve being almost immobile, and with no detectable inflow. There was severe hypoplasia of the infundibulum. The left ventricle was large, with very poor contractility. The left coronary artery was noted to have systolic and diastolic to and fro flow, but its connection could not be demonstrated either to the aorta or the pulmonary trunk. A separate right coronary artery was not identified. An aortic root angiogram showed no filling of the coronary arteries. Left ventriculography confirmed severe systolic dysfunction.

The prognosis and therapeutic options for the baby were discussed with the family, and they opted for compassionate care. The baby died later that day.

Autopsy findings

The left coronary artery was found to be connected to the right ventricle via fistulous communications, but had no connection to the aorta (Fig. 2). A right coronary artery was not identified. The tricuspid valve was small, at 3 mm in diameter, and was dysplastic but probe patent. The fistulous communications originated in the region of a small aneurysm at the apex of the hypoplastic right ventricle. There was extensive mottling of the subendocardium, and the cut surfaces of the left ventricular myocardium. Microscopic examination confirmed this to be hypoxic or ischemic damage. This myocardial injury was of varying ages, with areas of scarring and calcification indicating that an ischemic insult had occurred prior to the birth of the baby.

Figure 2. Anterior surface of heart at the base showing the left coronary artery (arrow) arising from the opened right ventricle, and lacking any connection with the aorta. The terminal branches of the left circumflex coronary artery are seen on the bottom right of the figure. MPA: pulmonary trunk; Ao: aortic root; LCA: left coronary artery.

Discussion

This case is, to our knowledge, unique in that the fetus developed left ventricular failure prior to birth. We speculate that myocardial perfusion, which was dependent on right ventricular volume, decreased as flow across the tricuspid valve decreased with the progression of the stenosis. Since there was no connection between the coronary arteries and the aorta, there was no other source of myocardial blood flow. Increasing myocardial ischemia, and eventually failure, thus occurred. Progressive stenosis of the coronary arteries cannot be ruled out as a contributing factor. This rare complication could not be predicted from the early antenatal ultrasound study.