85% of all cases of ALCAPA present within the first two months of life. However, symptoms may be misinterpreted (as in our case) or even be absent. In adult life patients with ALCAPA could present with symptoms of heart failure, mitral valve insufficiency, angina or arrhythmias. There are two potential substrates for arrhythmias in these patients. Firstly, areas with scar tissue after previous myocardial infarctions (MI) may alter the conduction in the left ventricle and become arrhythmogenic. Secondly, arrhythmias could be triggered from an acute ischemic event during exercise, where coronary steal phenomena may cause inadequate perfusion. Syncope due to ventricular tachycardia (VT) or cardiac arrest due to VF is therefore a major clinical presentation of ALCAPA in adults.
Objective findings include cardiomegaly on chest X-ray, and ECG may display an anterolateral infarct pattern. In children, the diagnosis can often be made by two-dimensional echocardiography with direct visualization of the abnormal origin of the left coronary artery and retrograde flow into the pulmonary artery. However, in adults the origins of the coronary arteries may be difficult to visualize, and in cases where the clinical suspicion is strong, a coronary angiography or CT-angiography should be performed.
In cases of ALCAPA several surgical treatment options have been proposed. Ligation of the anomalous artery at its origin in order to prevent coronary steal phenomena is one option, but this method depends on extensive collateral supply from the right coronary artery. An alternative percutaneous treatment approach was recently introduced by which the left coronary artery was closed by device embolization in a patient with large collaterals and coronary steal phenomena [8]. Today surgical procedures are aimed at creating a two-coronary system either via 1) a bypass graft (mammary artery or saphenous vein) in combination with ligation of the anomalous artery, 2) the Takeuchi-procedure where an intrapulmonary tunnel from the aortopulmonary window to the coronary artery is created or 3) translocation of the left coronary artery from the pulmonary trunk to the aortic sinus [9, 10]. The latter depends on the distance between the origin of the anomalous artery and the aorta, but is possible in the majority of the cases [11].
In infants, most of the patients with corrected ALCAPA show normalization of both ventricular function and mitral valve insufficiency [12, 13]. Estimated long-term survival at 20 years was recently shown to be 94.8% [13]. Simultaneous correction of the mitral valve insufficiency can be performed, but conservative treatment is often recommended as mitral valve function improves spontaneously.
No long-term studies of large populations of adults with corrected ALCAPA are available, but the prognosis is generally good. The late outcome after revascularization mainly depends on the extend of irreversible impaired left ventricular function and the presence of myocardial scar tissue.
Restoration of a dual coronary system will prevent further ischemia and arrhythmias of acute ischemic origin, but the anatomical substrate for ventricular arrhythmias in patients with old MI will not be altered after revascularization. As in other patients with a history of VT/VF not associated to an acute ischemic event, antiarrhythmic treatment must be considered. Treatment options include drug therapy, ICD implantation or catheter ablation. ICD implantation has been shown to be superior to drug treatment in patients with a history of VT/VF and previous MI (secondary prophylaxis) – especially when there is left ventricular dysfunction [14]. With recurrent VT refractory to these treatment options, direct surgical ablation or resection of the arrhythmogenic focus is an option
ICD implantation may also be considered in patients without a history of arrhythmias, when there is marked left ventricular dysfunction and electrophysiological study shows inducible VT (primary prophylaxis) [15].
In conclusion, the diagnosis of ALCAPA should be considered in adults without evidence of ischemic heart disease presenting with arrhythmias, left sided heart failure with or without mitral valve dysfunction, since an early diagnosis and surgical treatment generally results in an excellent prognosis.
