Monocular amaurosis fugax as the heralding symptom of vasovagal syncope Behzad B. Pavri, MD,* Kristin Roussillon, MD,* Jason Hsu, MD, † James McBride, MD* From the *Department of Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, and the † Retina Service of Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania. A 60-year-old man presented with his 8th episode of syncope over the past 6 months. Each of these episodes had occurred while he was standing or seated, and the first symptom he experienced was “a curtain falling” across his right eye only. Within moments, he would develop nausea (sometimes progressing to vomiting), profound diaphoresis, yawning, increased salivation, and lightheadedness; blind- ness in his right eye would persist during this entire period. Over the next few minutes, he would progress to complete loss of consciousness, followed by prompt and spontaneous recovery. He was often fatigued for hours after these events, but visual recovery was prompt. Neither the patient nor bystanders described seizure activity, bladder or bowel in- continence, or tongue bite. His vital signs and physical examination were entirely normal by the time he was eval- uated after each syncopal event. An extensive evaluation had been performed over the past 6 months. (1) Resting electrocardiogram (ECG) showed normal sinus rhythm with a short PR interval but without obvious pre-excitation; an electrophysiology con- sultant had recommended an electrophysiology study to exclude re-entrant arrhythmias as a cause for syncope. Upon further review, it was determined that the ECG did not show pre-excitation, but was consistent with accelerated atrioven- tricular nodal conduction, the so-called Lown-Ganong-Le- vine syndrome. 1 (2) Blood tests did not reveal any abnor- malities. (3) Echocardiography revealed normal chamber size and function without wall motion abnormalities; mod- erate aortic regurgitation was noted, but left ventricular dimensions were normal. (4) Head-up tilt table testing re- sults were positive, with exact reproduction of his clinical syndrome including loss of vision in the right eye associated with a decrease in blood pressure, followed by loss of consciousness. (5) Carotid ultrasound showed occlusive/ pre-occlusive disease of the right internal carotid artery. (6) Head computed tomography (CT) showed no acute intra- cranial process. (7) A CT perfusion study showed entirely symmetric perfusion of both hemispheres at rest. (8) Mag- netic resonance imaging (MRI) of the brain showed no acute infarct and mild prominence of ventricles and sulci compatible with age-related cerebral volume loss. There was no evidence of intraparenchymal hemorrhage, cerebral edema, mass or mass-effect, or restricted diffusion to sug- gest an acute ischemic event. No chronic lacunar infarcts were detected, and there were no microangiopathic changes to suggest prior microemboli. (9) Magnetic resonance an- giography (MRA) of the neck vessels showed complete chronic occlusion of the right internal and external carotid arteries, with filling of the right anterior and middle cerebral arteries via the circle of Willis. Flow was normal in the left carotid and both vertebral arteries. Discussion We describe an unusual case of monocular amaurosis fugax as the presenting symptom of vasovagal syncope. The de- scription of blindness in the right eye initially prompted an evaluation for a thromboembolic source, but there was no evidence for a stroke or intracranial bleed. Although an em- bolic cause of amaurosis fugax is plausible, one would expect embolic phenomena to occur unpredictably rather than as consistently linked to a typical prodrome of vagal activa- tion, as described by our patient. The discovery of an oc- cluded right carotid system allowed us to speculate that vagally mediated hypotension may have resulted in de- creased perfusion to the ipsilateral central retinal artery. Symmetric perfusion of both hemispheres on the resting CT flow study may at first seem to refute the idea that the right eye was more susceptible to ischemia; however, that may simply be reflective of well-compensated circulation under normotensive conditions. The central retinal artery (a true end-artery without any collateral vessels) is a branch of the ophthalmic artery, which arises as a branch of the internal carotid artery before the circle of Willis (Figure 1). The central retinal artery enters the optic nerve close to the eyeball, sending branches over the internal surface of the retina, and these terminal branches are the only blood supply to the inner retina. Orihashi et al 2 showed by transocular Doppler ultrasonog- raphy that on average, central retinal artery flow ceased KEYWORDS Syncope; Vasovagal; Amaurosis ABBREVIATIONS ECG = electrocardiogram; CT = computed tomography; MRI = Magnetic resonance imaging; MRA = Magnetic resonance angiography (Heart Rhythm 2010;7:1129 –1130) Address reprint requests and correspondence: Dr. Behzad B. Pavri, 925 Chestnut Street, Suite 200, Philadelphia, Pennsylvania 19107. E-mail ad- dress: behzad.pavri@jefferson.edu. (Received April 13, 2010; accepted April 24, 2010.) 1547-5271/$ -see front matter © 2010 Heart Rhythm Society. All rights reserved. doi:10.1016/j.hrthm.2010.04.034