Left coronary artery arising from the pulmonary artery (ALCAPA) is a rare but serious form of congenital heart disease. -ALCAPA is relatively rare, with an incidence of approximately 1 in 300,000 live births and accounts for 0.5% of all congenital heart disease. The cause may be an abnormal separation of the main and pulmonary arteries during fetal life or the persistence of a pulmonary artery endothelial bud that is connected to the forming left coronary artery (LCA).ALCAPA may be present alone or in combination with other cardiac anomalies such as ductus arteriosus, ventricular septal defect, tetralogy of Fallot, and aortic constriction. The diagnosis of this disease is dependent on imaging and, if left untreated, the mortality rate is high, with approximately 90% of children dying within the first 12 months of life. However, a small number of patients develop a rich collateral circulation between the right and left coronary arteries and survive into adulthood, eventually dying of heart failure or sudden cardiac death. The manifestations of this disease have been reported more frequently both at home and abroad, but most of them have small sample sizes. In this study, the clinical features and long-term prognosis of this disease were described by summarizing the clinical cases of ALCAPA patients admitted to Beijing Anzhen Hospital. DATA AND METHODS 1. Clinical data: Since the first report of infantile ALCAPA in Beijing Anzhen Hospital in 1993, 23 patients with ALCAPA have been admitted to our hospital, and all of them were confirmed by cardiac ultrasound, catheterization, coronary CT or intraoperatively. Among them, 13 cases were males and 10 cases were females, and 16 patients were within 12 months of the age of onset. 2. ECG examination The normal range of the electrocardiographic axis and the definition of abnormal Q waves were referred to the relevant literature [1]. The abnormal Q waves were defined as the time limit of Q waves ≥ 0.03 s, or the depth of Q waves more than 1/4 of the R waves in the same lead, or the depth of Q waves ≥ 3 mm in lead I and ≥ 2 mm in lead avL. ST-segment depression referred to ST-segment depression ≥ 0.05 mv. 3, Cardiac ultrasound examination Transthoracic 2D ultrasound and Doppler flow imaging were performed through the diagnostic cardiac ultrasound machine to observe the left and right coronary artery openings, the Coronary artery alignment and flow direction, abnormal shunts in the pulmonary artery, recording cardiac function, heart size, valve regurgitation, ventricular wall motion, endocardial thickness, and right coronary artery opening and aortic root diameter. 4.Catheterization imaging examination Routine disinfection and towel laying, after anesthesia, the right femoral artery and vein were punctured and a 5-6F sheath was placed. Right heart catheterization was performed to obtain hemodynamic information. A pigtail catheter is fed to the aortic root for ascending aortography. In adult patients, selective coronary angiography is performed to determine the opening and course of the coronary arteries, the direction of blood flow, collateral circulation and shunt. 5.Surgery The surgical procedure is selected according to the preoperative examination, the location of the left coronary artery (LCA) opening in the pulmonary artery, and the distance from the aortic root. 6.Follow-up Patients were followed up after surgery by outpatient, telephone, letter, and e-mail. Patients were asked about their symptoms, changes in ECG were recorded, and cardiac function, left intraventricular diameter, mitral regurgitation, suprapulmonary stenosis, and artificial coronary artery were evaluated by cardiac ultrasound. RESULTS 1. Symptoms Among patients aged ≤12 months, 5 (31.3%) were seen for heart failure, 7 (43.8%) for pneumonia, 2 (12.5%) for pneumonia combined with heart failure, and 2 (12.5%) for recurrent upper respiratory tract infections with heart enlargement. 11 (68.8%) had a history of heart failure during the course of the disease and 9 (56.3%) had a history of pneumonia. The children often presented with shortness of breath, feeding difficulties, pallor, excessive sweating, and lack of weight gain. At the first visit, 9 (56.3%) children were diagnosed with endocardial elastosis (EFE), 3 (18.8%) with dilated cardiomyopathy (DCM), 1 (6.3%) with myocardial infarction, and only 3 (18.8%) with ALCAPA. in the early 6 cases, the admission diagnosis was still EFE, but with the experience gained in cardiac ultrasound diagnosis Six children were seen after 12 months of age. Clinical cardiac function at admission: Class I (3 cases), Class II (5 cases), Class III (7 cases), and Class IV (1 case). Among the patients with an age of onset >12 months, the two oldest patients presented with chest tightness during activity at the age of 43 and 63 years, respectively, and were diagnosed with bronchitis and old myocardial infarction at the first visit, and both were admitted with coronary artery disease. 4 cases presented with cardiac murmurs on physical examination, 2 of which were diagnosed as ALCAPA by ultrasound at the first visit, 1 was misdiagnosed as myocarditis, and 1 had One case was asymptomatic and was found to have mitral valve insufficiency at the age of 3 years by cardiac ultrasonography at a local hospital, and was admitted at the age of 13 years with a right coronary artery fistula. In 12 (75%) of the patients aged ≤12 months, cardiac enlargement was detected on examination, and 12 (75%) had a grade I-II systolic murmur in the apical region or between the II-IV intercostal spaces at the left sternal border. Among patients admitted at >12 months of age, one had a grade III continuous murmur between the II-IV intercostal spaces at the left sternal border, two had a grade III-IV systolic murmur between the II-IV intercostal spaces at the left sternal border, three had a grade II systolic murmur at the apex of the heart, and one had no heart murmur. All patients had no cyanosis and edema. In 15 patients with age of onset less than 12 months, there were abnormal Q waves with T-wave inversion in leads I, avL, and V4-V6, which were most obvious in the avL lead, and all had deep and wide Q waves. Among the 7 patients with age of onset >12 months, 2 had abnormal Q waves in avL leads but none in I. One 66-year-old male patient presented with atrial fibrillation, left anterior branch block, ECG axis -33 degrees, QRS wave group in leads V1-V3 with QS pattern and upright T waves, and had been diagnosed with old myocardial infarction. 4 cases had no abnormal Q waves in all leads, and 1 of them had normal ECG. Two cases had ST-segment depression in leads I, avL, V4-V6, T-wave inversion or bidirectional, and one case had ST-segment depression in leads I and avL only, but had transient ST-segment elevation in leads II, III, avF, V3-V6 after admission. 4. Chest radiograph Twenty-one patients underwent chest radiography, which may show pulmonary stasis and enlarged heart shadow. Cardiothoracic ratio and left ventricular enlargement were higher in patients with age of onset ≤12 months, while protrusion of the pulmonary segment was more common in patients with age of onset >12 months. All patients underwent cardiac ultrasonography, and the main findings are shown in Table 3. LVEF was lower in patients aged ≤12 months, with LVEF >50% in 8 cases (50%), 35%-50% in 6 cases (37.5%), and ≤35% in 2 cases (12.5%). Moreover, LV enlargement was more pronounced, and apical ventricular wall tumors, papillary muscle echogenicity enhancement and endocardial thickening were common. The right coronary artery (RCA) diameter was measured in 19 patients, and the ratio of RCA diameter to aortic root diameter (RCA/AO) exceeded 0.14 in all patients, with a significantly greater RCA/AO in patients >12 months of age than in patients ≤12 months of age. Among the patients with age of onset ≤12 months, the six children with age of admission older than 12 months had abundant collateral flow. Abundant collateral flow was common in patients with age of onset >12 months. In most patients, the LCA and pulmonary artery connections were detected on 2D ultrasound, and color Doppler imaging often revealed predominantly diastolic flow into the pulmonary artery. intramural coronary arteries were seen in one patient. In one patient with age of onset ≤12 months, EFE was misdiagnosed in one early stage patient; in one patient with age of onset >12 months, right coronary artery pulmonary fistula, right coronary artery right ventricular fistula (multiple), and left coronary artery dysplasia were misdiagnosed, and in the other patient, mitral stenosis (mild) with incomplete closure (moderate) and mild pulmonary artery hypertension were seen on ultrasound. The diagnosis was confirmed by aortogram after admission. In 9 patients, right heart catheterization was performed, and 7 patients had significant left-to-right shunts, with the proportion of shunts in the pulmonary circulation ranging from 10.1% to 57.6%, with a mean value of (30.2±17.2%), and 2 patients had no significant shunts. 3 patients were found to have mild pulmonary hypertension. 12 patients underwent ascending aortography, and intraoperative RCA was seen to emanate from the right coronary sinus of the aorta, but not from the left coronary artery (LCA). After the RCA was visualized, the contrast agent reversed the LCA through the collateral circulation and eventually flowed into the pulmonary artery. One patient had sudden cardiac death after admission and another was discharged automatically after refusing further consultation. 21 patients received surgical treatment, including one early left coronary artery ligation, seven Takeuchi procedures, and 13 left coronary artery reimplantations. 3 cases underwent mitral valvuloplasty, two mitral valve replacements, and three ventricular wall tumor resections at the same time. The duration of extracorporeal circulation (CPB) ranged from 90 min to 362 min, with a mean of (177±76) min, and the duration of cardiac flow block (CID) ranged from 51 min to 178 min, with a mean of (107±36) min. 6 patients died postoperatively, including 1 death due to posterior pulmonary artery wall bleeding, heart failure, and ventricular fibrillation, 1 death due to bleeding from the LCA and AO anastomosis, and 4 cases died of low cardiac output. The duration of postoperative ICU monitoring in other cases ranged from 13h to 788h, with a mean of (221±236) h. The duration of retained tracheal intubation ranged from 7h to 406h, with a mean of (79±111) h. Discussion Patients with ALCAPA at different age of onset have different clinical features, which are determined by the pathogenesis of ALCAPA. In the neonatal period, pulmonary vascular resistance and pulmonary artery pressure are high, and the abnormal origin of LCA is supplied by the pulmonary artery, so it does not cause significant myocardial ischemia. One to two months after birth, pulmonary vascular resistance and pulmonary artery pressure begin to decrease, and the RCA supplies blood to the LCA through side branches. At this time, if an extensive collateral circulation is not formed between the LCA and RCA, it can lead to myocardial ischemia and necrosis in the LCA blood supply area, and left ventricular enlargement and impaired cardiac function. In the infantile form, patients often present with respiratory infections and heart failure in the first few months of life, and ALCAPA is often misdiagnosed as EFE and DCM. In this study, less than 20% of the infantile cases were diagnosed as ALCAPA at the first visit, but if extensive collateral circulation is formed in infancy and the myocardium is adequately perfused, severe myocardial ischemia does not occur at this time. In this study, young patients with onset after 1 year of age were mostly asymptomatic, but were often seen with a heart murmur on examination due to the presence of a left-to-right shunt and varying degrees of mitral regurgitation. However, as the disease progresses, the LCA gradually becomes a channel for shunting from the RCA to the pulmonary artery, i.e., coronary artery steal, so older patients may present with angina pectoris due to myocardial ischemia. Previous studies have shown that ECG can help in the differential diagnosis of infantile ALCAPA. a study by Chang et al [2] pointed out that the depth of Q wave in avL leads ≥3 mm with T-wave inversion is an important indicator to differentiate ALCAPA from DCM. Our experience also suggests that the presence of abnormal Q waves with ST-segment depression and T-wave inversion in leads I, aVL, and V4-V6 of the electrocardiogram is of great value in differentiating ALCAPA from EFE [3]. A summary of cases from our institution shows that the ECG of infantile ALCAPA patients has distinctive features, with abnormal Q waves with T-wave inversion in the anterolateral leads, which are most obvious in the avL leads, all with deep and wide Q waves. In contrast, adult patients often lack specificity in their ECG presentation. In some young patients, the avL leads show abnormal Q waves with T-wave inversions, while the I leads have no abnormal Q waves, which may be an important indication for the diagnosis of this disease. Some patients had ST- T changes in the anterolateral wall leads only, and another elderly patient had ECG changes of anterior interval wall myocardial infarction, which could be easily misdiagnosed as myocarditis or coronary artery disease. The diagnosis of ALCAPA can be made if the LCA and pulmonary artery connection are found on 2D echocardiography, and color Doppler flow imaging can further improve the accuracy of the diagnosis. However, some indirect manifestations may also suggest the presence of ALCAPA and should be taken seriously. The most common ultrasound manifestations are left ventricular enlargement and varying degrees of mitral regurgitation, but they lack specificity and can be misdiagnosed as dilated cardiomyopathy and valvular disease. Previous pathological studies have found that the anterior wall myocardium of the left ventricle in pediatric patients can have localized fibrosis, most pronounced in the apical region; fibrosis can also involve the endocardium and manifest as diffuse elastic fiber hyperplasia [4]. In our study, apical ventricular wall tumors and endocardial thickening were often seen in patients with the infantile form, consistent with the pathological presentation. Thickening of the endocardium is easily misdiagnosed as EFE and is highly suggestive of ALCAPA if accompanied by characteristic electrocardiographic changes.Papillary muscle echo enhancement as a sign of papillary muscle ischemia is common in infantile patients but was also seen in two adult patients, and both had varying degrees of mitral valve insufficiency and left ventricular enlargement, indicating some degree of myocardial ischemia.A study by Chang et al [2 pointed out that papillary muscle echo enhancement is an important indicator to differentiate ALCAPA from DCM. Previous studies have shown that RCA/AO can be used for the differential diagnosis of ALCAPA and DCM [2,5]. All patients in this study had RCA/AO ≥ 0.14, and RCA expansion was more pronounced in adult-type patients. More abundant collateral flow in the septum and left ventricular wall was seen in some patients and was more common in patients admitted older than 12 months. Previous experience also suggests that collateral flow in the ventricular septum is more common after infancy and in patients without significant symptoms [6]. Therefore, dilated RCA and abundant collateral circulation are crucial for the survival of patients with ALCAPA. References [1] Garson A JR, Bricker JT, Fisher DJ, et al. The Science And Practice of Pediatric Cardiology. second Edition. Williams & Wilkins , 1998. 735-788. [2 Chang RR, Allada V. Electrocardiographic and echocardiographic features that distinguish anomalous origin of the left coronary artery from pulmonary artery from idiopathic dilated cardiomyopathy. Pediatr Cardiol, 2001, 22(1):3-10. [3] Guo BJ, Han L, Jin M, et al. Diagnostic value of electrocardiography in infants with left coronary artery originating from the pulmonary artery. Chinese Journal of Pediatrics, 2004, 42(11): 863-864. [4] John D. Keith. The anomalous origin of the left coronary artery from the pulmonary artery. Heart, 1959, 21:149-161. [5 ] Koike K, Musewe NN, Smallhorn JF, et al. Distinguishing between anomalous origin of the left coronary artery from the pulmonary trunk and dilated cardiomyopathy: role of echocardiographic measurement of the right coronary artery diameter. Br Heart J, 1989, 61(2):192-7. [6] Hildreth B, Junkel P, Allada V, et al. An uncommon echocardiographic marker for anomalous origin of the left coronary artery from the pulmonary artery: visualization of Pediatr Cardiol, 2001, 22(5):406-8.