single coronary artery ( sca ) is a rare congenital anomaly of the coronary arteries arising from a single coronary ostium1 ) .
the clinical significance of sca is not clear , and it is generally considered to be a benign entity .
there are some case reports of sca in adults , but there are a few such reported cases in children .
we report a case of a 13-year - old girl with right coronary artery arising from the left circumflex artery who presented with chest pain .
a previously healthy 13-year - old girl visited our emergency department due to left - sided chest pain that had occurred suddenly 10 hours ago .
the pain was continuous pressing in nature without any radiation , and it improved on bending forward but worsened with deep inspiration .
she had no specific past medical history such as kawasaki disease , asthma , and no family history of heart or lung disease .
she did not appear ill ; and her vital signs were as follows : blood pressure was 133/79 mmhg , heart rate was 117 beats / min , and temperature was 37.6. her weight was 40 kg .
the physical examination did not reveal any other specific findings , especially her lung sound was normal electrocardiogram ( ecg ) showed sinus tachycardia with a heart rate of 114 beats / min without st segment changes ( fig .
however , her cardiac enzyme levels were slightly elevated ; n - terminal prohormone brain natriuretic peptide was 257.6 pg / ml , troponin i was 2.138 ng / ml , and creatine kinase - myoglobin ( ck - mb ) was 13.02 ng / ml . the next day , she again complained of severe chest pain .
her ecg was taken again , and it showed marked st elevation in the v4-v6 left precordial leads and inferior leads and st depression in avr lead , which was suggestive of myocardial ischemia ( fig .
2 ) . also , her cardiac enzyme levels were elevated ; troponin i was 4.310 ng / ml , ck - mb was 10.78 ng / ml . although the chest pain regressed spontaneously , further evaluation was performed .
we performed coronary angiography ; left coronary artery ( lca ) was bifurcated normally into left anterior descending ( lad ) and left circumflex ( lcx ) coronary arteries , and it showed the absence of normally originating right coronary artery ( rca ) .
an aberrant branch was extended from the distal lcx , which crossed the crux and continued to the right atrioventricular groove , covering the territory of the rca ( fig .
lad and its branches ( septal perforator branch , diagonal branch ) also had no stenotic lesion .
we also performed cardiac computed tomography and confirmed the absence of the rca and the presence of a well - developed lcx coronary artery covering the right side of the heart ( fig .
she was discharged without any medications ; however , a regular follow - up was recommended .
an isolated sca is defined when only one coronary artery arises from the aorta by a single coronary ostium , supplying the entire heart1 ) .
sca is a very rarely encountered disease entity , and its reported incidence in adults is only from 0.024% to 0.066%1,2 ) .
also , it is occasionally associated with other cardiac anomalies such as transposition of the great vessels , a coronary arteriovenous fistula , or a bicuspid aortic valve3 ) .
a sca can result in the development of cardiac ischemia , cardiomyopathy , and congestive heart failure4 ) .
myocardial ischemia may occur if there is only insignificant or absent coronary artery narrowing . based on lipton classifications1 )
, the first division was made between the right - type ( r ) and left - type ( l ) according to the site of origin of sca .
next , the artery was designated as group i , ii , or iii depending on its anatomical course
group ii anomalies arise from the proximal part of the normal rca or lca , and cross the base of the heart before assuming the normal position of the inherent coronary artery .
group iii describes the anomaly where the lad and lcx arise separately from the proximal part of the normal rca . according to this classification1 ) ,
our patient was classified as l - i type , which is the presence of a markedly dominant lcx artery but the absence of a rca
. there would be some published reports of an anomalous rca arising from the lad5,6 ) , but the reported cases of an anomalous rca originating from the lcx are relatively less7,8,9,10 ) .
but , there are only a few cases in the pediatric and adolescent age group ; these anomalies are rarely suspected or identified during life and are usually first recognized at autopsy , largely because there is insufficient clinical suspicion as well as the difficulties implicit in routine examination or clinical testing for these malformations12 ) .
mostly , sca has a benign course , and it is known that sca does not interfere with coronary perfusion . but some reports stated that patients with sca could develop significant ischemic heart disease13 ) , and the patients with sca who usually present with myocardial infarction have stenosis of the coronary artery .
especially , the r ii - iii type and l ii - iii type anomalies , having a coronary artery branch following a dangerous course , may predispose to fatal myocardial ischemia .
but there were some reports suggesting that the incidence of coronary artery bypass graft in patients with l - i type of anomaly such as the rca originating from the lcx was about 33%9 ) .
sca was incidentally detected on angiography while we were evaluating the patient for chest pain .
our patient had abnormal ecg showing st - elevation in inferior leads and left precordial leads with reciprocal change in avr and elevated cardiac enzyme levels suggesting myocardial ischemia .
the cause of myocardial ischemia was uncertain , because there was no stenosis and the result of treadmill test was negative .
certain mechanisms could be considered , such as the coronary steal phenomenon due to the abnormal vessel or microvascular damage , and slow controlled ischemia caused by long travel distance of abnormal coronary artery7 ) .
there is a report of a case similar to our patient , in which there was no stenosis , but the authors thought that the patient had myocardial ischemia due to an abnormally slow coronary flow in the rca , because there was abnormally slow angiographic filling in the rca territory7 ) .
hence , they treated the patient with calcium channel blockers like diltiazem and nitrates , and the chest pain resolved after taking medications .
the cause of chest pain can be considered to be coronary artery spasm - induced myocardial ischemia10 ) . since we did not perform coronary artery spasm test such as the ergonovine test , the diagnosis of coronary artery spasm could not be definitely excluded .
we advised her to avoid heavy exercise and to develop healthy eating habits to prevent atherosclerosis .
also , we explained to the patient that she might need to take medications and to undergo a regular follow - up of symptoms .
if a patient complains of chest pain due to sca , but does not exhibit significant stenotic lesions in the sca on coronary angiography like our patient , other tests should be considered .
we have to consider performing stress tests such as single photon emission computed tomography , treadmill test whether or not myocardial
and strategies for clinical identification of coronary artery anomalies are as follows : if clinical symptom such as exertional syncope or chest pain appears , physicians have to consider noninvasive examination like transthoracic or transesophageal echocardiography .
and then , sonographer can not find coronary arteries from their usual coronary sinuses , we may suggest further examination such as coronary arteriography or computed tomography .
we believe that this is the first report of a pediatric case of sca with rca originating from the lcx artery in korean population . therefore , although it is very rare , we can consider the diagnosis of coronary artery anomaly in pediatric patients with an unusual presentation of myocardial ischemia .
 the presence of a single coronary artery is a rare congenital anomaly ; such patients often present with severe myocardial ischemia . 
 we experienced the case of a 13-year - old girl with the right coronary artery originating from the left circumflex artery . 
 she visited our emergency department owing to severe chest pain ; her cardiac enzyme levels were elevated , but her initial electrocardiogram ( ecg ) was normal . 
 echocardiography showed normal anatomy and normal regional wall motion . 
 when she presented with recurrent chest pain on admission , the ecg showed significant st - segment elevation in the left precordial leads and inferior leads with st - segment depression in avr lead , suggesting myocardial ischemia , and her cardiac enzyme levels were also elevated . 
 we performed coronary angiography that showed a single right coronary artery originating from the left circumflex artery without stenosis . 
 we confirmed the presence of a single coronary artery using coronary computed tomography . 
 in addition , the treadmill test that was performed showed normal results . 
 she was discharged from the hospital without any medications but with a recommendation of a regular follow - up . 
Introduction
Case report
Discussion