The images provided demonstrate a left main coronary artery arising anomalously from the PA, a condition referred to as Bland-White-Garland syndrome or anomalous left coronary artery originating from the PA (ALCAPA), and a significantly dilated left ventricle (Figure 1, Figure 3).
Coronary arteries originating anomalously from the PA have been documented as far back as the 1800s.[2,3] Although most coronary artery anomalies arise from the aorta, less than 0.4% of patients with congenital cardiac anomalies have coronary vessels that originate from the PA (approximately 1 in 300,000 live births in the United States).
Coronary vessel formation begins at approximately 32 days' gestation. Abnormal division of the conotruncus into the aorta and PA or abnormal involution and persistence of an endothelial bud on a pulmonary sinus may lead to an aberrant connection to the developing coronary artery. In 1933, Bland, White, and Garland diagnosed the syndrome of early progressive heart failure associated with anomalous origin of the coronary arteries arising from the PA in a 3-month-old child at autopsy. The anomaly is most often a single left coronary artery rather than a right coronary artery. In some instances, the left circumflex artery and the left anterior descending artery may also have separate origins from the PA.
Although the clinical presentation may vary depending on the coronary artery involved, as well as its size and distribution, in most cases significant hemodynamic compromise is present, with ensuing myocardial ischemia and progressive ischemic cardiomyopathy. If left untreated, mortality has been reported to be as high as 90% within the first year of life. Prompt diagnosis and treatment are necessary in cases in which both the left and right coronary arteries arise from the PA (a less common variant of Bland-White-Garland syndrome) because the condition is not compatible with survival.
The symptoms of angina in an infant may include feeding intolerance, irritability or respiratory distress when crying, diaphoresis, pallor, failure to thrive, and even shock. Early symptoms may temporarily be masked by the presence of large collateral vessels. Rarely, the onset of symptoms in children may include precordial pain, dyspnea and tachypnea, shortness of breath, exertional chest pain, syncope, and even sudden cardiac death. Upon the normalization of physiologically elevated neonatal pulmonary vascular resistance in the first 4-6 weeks of infancy, the low perfusion pressures and low oxygen saturation characteristic of the PA lead to myocardial ischemia and progressive cardiomyopathy.
Demand ischemia caused by anomalous coronary arteries from the PA is not noted prenatally because the parallel circulatory system provides relatively equivalent oxygen concentrations and pressures between the aorta and main PA through the patent ductus arteriosus (PDA). With the formation of a collateral blood supply between the right and left coronary systems, the symptom onset may be delayed; however, coronary steal phenomenon may occur as a result of the higher-pressure collateral vessels and retrograde flow into the PA from the anomalous coronary artery, should collaterals arise from normal coronary arteries.  If left untreated, coronary steal will exacerbate the symptoms of heart failure and accelerate the complications associated with ischemia, cardiomyopathy, and pulmonary hypertension.
Medscape © 2023 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Shah Azmoon, Matthew Budoff, David Atkinson. Pediatric Case Challenge: Alarming Symptoms in a Toddler Who Had Myocarditis and Recently Immigrated - Medscape - Jan 17, 2023.