Letter by Sarikaya et al Regarding Article, “A Sensitive Dissection: Profound Bradycardia Complicating Carotid Dissection”
To the Editor:
We read with great interest the recent article by Dulay et al.1 The authors present a 49-year-old woman with a history of vasovagal syncope who lost consciousness because of a sinus arrest while she was being treated with intravenous tissue plasminogen activator for a stroke in the right middle cerebral artery territory involving the insular cortex. The stroke was due to a spontaneous dissection of the cervical internal carotid artery that occluded the dissected vessel down to the carotid bulb.1 We were surprised to read the authors’ hypothesis that the sinus arrest resulted from “mechanical pressure to an already sensitive carotid sinus from thrombus secondary to internal carotid artery . . . in this patient who was prone to vasovagal syncope.” If a thrombus occludes the carotid bulb, one would expect less arterial pressure acting on the wall of the bulb and the carotid sinus. Thus, it seems unlikely that arterial pressure exerted on the carotid bulb was the cause of sinus arrest. Furthermore, we reviewed our dissection data bank, which includes 136 patients with an internal carotid artery causing carotid occlusion and ischemic stroke in the middle cerebral artery territory, and found no patient with sinus arrest. Finally, if the assumption of the authors were correct, some patients with acute atherosclerotic occlusion of the internal carotid artery should suffer cardiac arrest, and such an important complication would be expected to be reported. However, we found no such publication in an extensive search that was performed in MEDLINE (January 1966 to September 2008) and EMBASE (January 1980 to September 2008) and that included checking all relevant articles for additional eligible studies using the following key words: “bradycardia,” “cardiac arrest,” “carotid dissection,” “carotid occlusion,” “sinus arrest,” and “internal carotid artery.”
In contrast, the right insula has been implicated in the autonomic control of cardiac activity, and acute ischemic stroke affecting the insular region may cause fatal or nonfatal cardiac arrest.2–4 It is thus likely that the cardiac arrest of the patient reported by Dulay et al resulted from an insular stroke and not from mechanical pressure on the carotid bulb.
Dulay D, Gould PA, Leung A, Krahn AD. A sensitive dissection: Profound bradycardia complicating carotid dissection. Circulation. 2008; 118: e152–e153.
Colivicchi F, Bassi A, Santini M, Caltagirone C. Prognostic implications of right-sided insular damage, cardiac autonomic derangement, and arrhythmias after acute ischemic stroke. Stroke. 2005; 36: 1710–1715.
Tokgözoglu SL, Batur MK, Topuoglu MA, Saribas O, Kes S, Oto A. Effects of stroke localization on cardiac autonomic balance and sudden death. Stroke. 1999; 30: 1307–1311.