Case description
A 16-year-old male with no previous medical history presented to the hospital after an aborted sudden cardiac arrest while at a soccer practice. He collapsed suddenly during a warm-up exercise and was identified as unresponsive and pulseless. Immediately after the event, an automated external defibrillator was placed by bystanders, and a shockable rhythm was detected. The automated external defibrillator then recommended defibrillation, which resulted in return to sinus rhythm. Shortly after emergency medical services arrived, the patient’s rhythm converted back to ventricular fibrillation, requiring two additional automated external defibrillator shocks, resulting in return to sinus rhythm. On initial evaluation, the patient had a Glasgow Coma Scale of 5, a heart rate of 104 bpm, a blood pressure of 134/77 mmHg, and an oxygen saturation of 100% with a respiratory rate of 29 on room air. Given the patient’s altered mental status with a Glasgow Coma Scale of 5, he was intubated for airway protection. His work-up included chest radiograph and CT of the head, which were unremarkable. An electrocardiogram showed normal sinus rhythm with ST-segment depression in the inferior leads and prominent QRS complexes in leads V1–V3 (Figure 1).
Electrocardiogram—normal sinus rhythm with ST-segment depression in the inferior leads and prominent QRS complexes in leads V1–V3.
Due to the aborted sudden death, he was evaluated by paediatric cardiology. A routine transthoracic echocardiogram demonstrated an anomalous origin of the right coronary artery off the left sinus of Valsalva with an acute angle take-off with a slit-like orifice, an intra-arterial course, and a suspected long intramural course. The remainder of the intracardiac anatomy was otherwise unremarkable, with normal right ventricular and left ventricular systolic function. For further elucidation of the coronary artery anatomy, a coronary CT angiogram confirmed the anomalous origin of the right coronary artery from the left coronary sinus with a long (17 mm) intramural course of the right coronary artery, demonstrated by the elliptical shape of the vessel (Figure 2). Also noted was the presence of a right-dominant coronary system. Cardiac MRI was performed to evaluate for other possible aetiologies of aborted sudden cardiac death, such as arrhythmogenic right ventricular cardiomyopathy. Cardiac MRI with late gadolinium enhancement and T2-weighted imaging demonstrated transmural T2 enhancement and late gadolinium enhancement suggestive of myocardial oedema and inflammation/scarring in the distribution of the right coronary artery (inferoseptal and inferior segments) (Figure 3). The clinical course revealed the patient regaining consciousness and being successfully extubated within 36 hours of the initial aborted sudden death event. Given concerns for the recent transmural infarction, cardiac surgery was delayed, allowing for any inflammation to improve. After a week, he underwent open-heart surgery. Surgical findings revealed both the left coronary artery and right coronary artery having a shared ostium with a subsequent right coronary artery that took an inter-arterial course that appeared intramural for about 17 mm. The operative approach included reimplantation of the right coronary artery to the right sinus of Valsalva. The patient was discharged from the hospital, five days after the repair, with multiple home medications, including metoprolol 50 mg twice daily, Lipitor 10 mg once daily, and aspirin 81 mg once daily. He was advised to refrain from gym and recess activities and was discharged with a continuously worn LifeVest. The LifeVest was recommended for this patient because of the full-thickness myocardial scar, which could serve as a nidus for arrhythmias. He was clinically well at his post-operative clinic visits. Post-operative echocardiogram demonstrated normal left ventricular systolic function with an ejection fraction of 62%, and mild reduced left ventricular function assessed by a global strain of -17.3% with localised reduction in the inferior wall region consistent with the area of infarction. Mild right ventricle dyskinesia was also seen. Repeat cardiac MRI was performed 3 months after the surgical repair, demonstrating persistent late gadolinium enhancement in the inferior septal and inferior segments of the ventricle, and a decision was made to place an automated implantable cardioverter-defibrillator, given the demonstration of persistent myocardial scar, which could serve as a nidus for future arrhythmia.
Coronary computed tomography angiography—demonstrates an anomalous origin of the right coronary artery from the left coronary sinus, and further defined a long intra-arterial segment of the right coronary artery.
Cardiac MRI with late gadolinium enhancement—demonstrates the anomalous origin of the right coronary artery, further demonstrates an inferior wall full-thickness infarct, which was in the exact distribution of the right coronary artery.
Discussion
Anomalous aortic origin of the right coronary artery is often identified incidentally on echocardiography. Management of anomalous aortic origin of the right coronary artery is controversial, but with reports of patients with sudden cardiac death and aborted sudden cardiac death, it suggests a subset of patients with increased risk for cardiac events.Reference Benjanuwattra, Abdelnabi, Leelaviwat, Cavazos, Sethi and Jenkins 1 Anomalous aortic origin of the right coronary artery can carry significant risk, particularly when it involves high-risk features. Currently, suggested high-risk features of an anomalous coronary artery include a slit-like coronary ostium as demonstrated by an acutely oblique proximal coronary course, an intramural course, and an inter-arterial course. Reference Frommelt, Lopez and Dimas2–Reference Bibevski, Ruzmetov, Turner and Scholl4 The patient presented in this case demonstrated multiple high-risk features of anomalous aortic origin of the right coronary artery, with a slit-like coronary ostium, a long intramural course, and an inter-arterial course.
This case suggests a correlation between sudden cardiac arrest and myocardial infarction localised to the distribution of the right coronary artery. Cardiac MRI revealed a transmural infarct of the inferior wall, corresponding to the right coronary artery distribution, suggesting ischaemic injury. This finding strongly supports the current theory of demand ischaemia as the underlying pathophysiology of sudden cardiac arrest in anomalous aortic origin of the right coronary artery.
Although in this case, the MRI findings followed an episode of sudden cardiac arrest, in other patients without aborted sudden cardiac death, the presence of a myocardial scar seen with late gadolinium enhancement on MRI may also serve as a critical indicator of previous ischaemic events and help identify patients at risk for future sudden cardiac death. Reference Cipriani, Lo Rito and Pica5,Reference Sachdeva, Ferrino and Doan6 The management of anomalous aortic origin of the right coronary artery depends on the presence of symptoms and evidence of myocardial ischaemia. Reference Poynter, Williams, McIntyre, Brothers and Jacobs7 This case suggests that an MRI-detected scar, even in the absence of ongoing symptoms, should be considered a high-risk feature warranting surgical evaluation. The current standard of practice by the American College of Cardiology and the American Heart Association includes surgical repair for patients with anomalous aortic origin of the right coronary artery that courses between the aorta and pulmonary artery if there is evidence of myocardial ischaemia. Reference Lawton, Tamis-Holland, Bangalore, Bates, Beckie and Zwischenberger8,Reference Kohlsaat, Gauvreau, Beroukhim, Newburger, Quinonez and Nathan9
Conclusion
Anomalous aortic origin of the right coronary artery is a challenging diagnosis that is associated with sudden cardiac death. High-risk features, including a slit-like orifice or a long intramural segment, may be associated with sudden cardiac death. Evidence of scarring on cardiac MRI aids in decision-making for the management of anomalous aortic origin of the right coronary artery.
Financial support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
None.
Clinical trial registration
Not applicable.
