coronary artery fistula ( caf ) is an unusual coronary artery abnormality , where connection exists between coronary artery and cardiac chamber or another blood vessel .
caf originating from the left main trunk and left circumflex artery is very unusual and rarely reported in the literature .
we describe a case of giant left main trunk and left circumflex artery fistula to the right ventricle .
a 24-year - old male patient presented with complaints of dyspnea and palpitation during exercise . on physical examination , his blood pressure was 120/80 mmhg and pulse rate was 75 bpm .
the heart was rhythmic and chest auscultation revealed a continuous murmur of grade 3/6 at the upper left sternal border .
transthoracic echocardiography ( tte ) showed enlargement of the left main trunk and left circumflex coronary artery , with a 25-mm inner diameter , diffusely tortuous dilated and drained into the posterior wall of the right ventricle [ figure 1 ] . left anterior descending artery , right coronary artery , and major side branches were normal .
the left ventricular systolic function was normal with an ejection fraction of 65% and there were no abnormalities in the regional wall motion and cardiac valves .
laboratory investigations were normal . in order to further evaluate the fistula in more detail , a 320-slice dynamic volume ct ( aquilion one ,
software release v. 4.3 , toshiba medical systems , japan ) angiogram was performed , using 3-dimensional volume - rendered ( vr ) and curved - plain reconstruction ( cpr ) .
it demonstrated a large fistula arising from the left main trunk and left circumflex artery emptying to the right ventricle [ figure 2 ] .
color - doppler echocardiography revealed enlarged and tortuous of lm and lcx ( white arrows ) origin from ao , abnormal flow from ao passing lm and lcx to rv through a fistula ( red arrow ) .
( ao : aorta , lm : left main trunk , lcx : left circumflex artery , lv : left ventricle , rv : right ventricle , ra : righe atrium , la : left atrium ) contrast - enhanced ct coronary angiogram .
3-dimensional volume - rendered ( vr ) and curved - plain reconstruction ( cpr ) shows origin and course of the fistula .
the vessel runs from the left main trunk and left circumflex coronary artery and drained into the posterior wall of the right ventricle through a fistula ( red arrow ) .
( ao : aorta , lm : left main trunk , lcx : left circumflex artery , lv : left ventricle , rv : right ventricle )
congenital caf is caused by a cardiovascular abnormality in embryo period , which accounts for 0.27 - 0.40% of all congenital cardiac defects .
acquired caf has been described after surgical procedures , endomyocardial biopsy , trauma , inflammation , atherosclerosis , and collagen vascular disease .
caf usually drains into the right chamber , pulmonary artery , pulmonary veins , superior vena cava , inferior vena cava , and coronary sinus .
most caf patients are usually asymptomatic and are found incidentally during angiographic evaluation for other cardiac diseases .
clinical symptoms of patients with caf are dependent on the size of fistula and the pressure of its terminal chamber . in our patient ,
the giant caf increases the volume load of the right heart chambers and the pulmonary artery .
if the shunt of caf is significant , steal blood phenomenon may occur and cause myocardial ischemia or infarction , which increases risk of infective endocarditis , accelerates atherosclerosis , and even heart failure .
generally , tte is an important primary non - invasive tool for diagnosis of coronary artery abnormality and confirmed by coronary angiography . with
the cardiac ct technological improvement in recent years , particularly in temporal / spatial resolution and reduced radiation dose , coronary computed tomography angiography ( ccta ) has been a relatively new imaging modality and non - invasive method for assessment of coronary artery disease .
ccta not only precisely demonstrate the origin , course , and drainage site of the fistula , but also provides surgical plan for treatment .
it is suggested that caf should be treated as soon as possible to avoid the potential risk of complications , no matter whether clinical symptom exists or not . in our case ,
he experienced no serious cardiac events over half a year of follow - up . in conclusion ,
the giant left main trunk and left circumflex artery fistula to the right ventricle are rarely seen .
 coronary artery fistula including the left trunk and left circumflex is uncommon . 
 we present a 24-year - old male patient with a giant left main trunk and left circumflex artery to right ventricle fistula , which is diagnosed by transthoracic echocardiography and coronary computed tomography angiography . in this paper , 
 the case report is to provide a better understanding of clinical characteristics for this disease . 
INTRODUCTION
CASE REPORT
DISCUSSION