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Syncope
Published in Henry J. Woodford, Essential Geriatrics, 2022
The carotid sinus is an area of dilatation of the internal carotid artery just distal to the carotid bifurcation (seeFigure 15.3). It contains a number of nerve receptors that sense change in pressure within the vessel wall (baroreceptors). Signals from these travel in a branch of the glossopharyngeal nerve (IX) to the medulla. From here, a vagally-mediated response can be triggered (seeFigure 15.4). Increased pressure within the vessel wall leads to peripheral vasodilatation and a reduction in HR, which lowers BP. In healthy individuals, this important mechanism maintains homeostasis of BP during changing physical activities.
Resetting of the Arterial Baroreflex: Peripheral and Central Mechanisms
Published in Irving H. Zucker, Joseph P. Gilmore, Reflex Control of the Circulation, 2020
Mark W. Chapleau, George Hajduczok, Francois M. Abboud
Another factor that modulates baroreceptor activity and may influence the degree of resetting is changes in blood flow. Increases in flow through the vascularly isolated carotid sinus increase carotid sinus nerve activity at equivalent pressure and strain (Fig. 10) and decrease the Pth of single baroreceptor units (Hajduczok et al., 1988). Thus, receptors in the carotid sinus may sense changes in blood flow in addition to changes in arterial pressure.
Brachiocephalic interventions
Published in Peter A. Schneider, Endovascular Skills: Guidewire and Catheter Skills for Endovascular Surgery, 2019
Patients are monitored overnight for cardiac and neurologic problems. It is not uncommon, especially in patients with a history of coronary artery disease, to have a heightened response to carotid sinus distension. It may require inotropic support for a time before the carotid sinus adapts to the radial force of the self-expanding stents. Avoiding extreme oversizing of the stents helps to decrease the incidence of post-CAS placement bradycardia and hypotension. The presence of significant hypotension in the absence of bradycardia is unusual in the immediate postprocedure period; it is worth emphasizing that other causes (e.g., retroperitoneal bleed related to access site problems) should also be excluded as the cause. Medications include aspirin (325 mg each day indefinitely) and clopidogrel (75 mg each day for 1 month). Follow-up includes duplex scan at intervals, as is performed after carotid endarterectomy.
Novel approaches: targeting sympathetic outflow in the carotid sinus
Published in Blood Pressure, 2023
Dagmara Hering, Krzysztof Narkiewicz
The importance of sympathetic origin as a critical mechanism underlying hypertension pathophysiology [6] is that emerging therapies have been developed to target sympathetic nervous system activity beyond neural control of the kidney where the RDN approach is specifically applied. Two device-based therapies for hypertension management have been developed to attenuate sympathetic outflow at the level of the carotid sinus. One therapeutic approach includes targeting the carotid body, a chemoreceptor organ that is involved in respiratory and cardiovascular control through complex neural pathways [7]. The second device-based approach is electrical or mechanical stimulation of carotid sinus baroreceptors whose sensitivity is reset in established hypertension, to a higher pressure and reduced in gain, to mediate changes in sympathetic activity to the heart and blood vessels [8].
Effectiveness and safety of implantable loop recorder and clinical utility of remote monitoring in patients with unexplained, recurrent, traumatic syncope
Published in Expert Review of Medical Devices, 2023
Pietro Palmisano, Federico Guerra, Vittorio Aspromonte, Gabriele Dell’Era, Pier Luigi Pellegrino, Mattia Laffi, Carlo Uran, Silvana De Bonis, Michele Accogli, Antonio Dello Russo, Giuseppe Patti, Francesco Santoro, Antonella Torriglia, Gerardo Nigro, Antonio Bisignani, Giovanni Coluccia, Giulia Stronati, Vincenzo Russo, Ernesto Ammendola
Before ILR insertion, all patients were evaluated by a multidisciplinary team of cardiologists, internists, neurologists and geriatricians, who were experienced in the management of syncope patients; they also underwent an extensive cardiac and neurological work-up in order to establish the etiology of syncope. The initial screening comprised a careful medical history (with description of the last syncopal episode, including the characteristics of syncopal onset and recovery and duration of the event), evaluation of medication, physical examination, resting ECG, two-dimensional echocardiogram and 24 h Holter or >24 h telemetry. The strategy was to continue the diagnostic work-up until the mechanism of syncope was clearly documented. Additional diagnostic procedures, if requested by physicians, were: carotid sinus massage (CSM), active standing test, 24-h ambulatory blood pressure monitoring, head-up tilt test (HUTT) [11], exercise tests, and electrophysiological study (EPS).
The role of carotid ultrasound in patients with non-lateralizing neurological complaints
Published in Hospital Practice, 2023
Shweta Varade, Abinayaa Ravichandran, Erafat Rehim, Hussam Yacoub, Rose Duncan, Hope Kincaid, Megan C. Leary, John Castaldo
While current guidelines address the use of CUS in patients with asymptomatic and symptomatic carotid disease, its utilization in patients with non-lateralizing neurological symptoms or focal neurological symptoms that are non-referable to the carotid artery is not addressed. The goal of our study is to evaluate the benefit of ordering CUS in patients presenting with non-carotid artery-related or other non-lateralizing neurological complaints in The Lehigh Valley Health Network. The large number of patients who undergo CUS testing for a wide variety of neurological complaints in our network provides an ideal cohort to evaluate and meet the objectives of our study. Carotid stenosis, however, can be associated with syncope in patients with carotid sinus hypersensitivity, a mechanism that was not considered in our patients.