RT-32
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Syncope in aortic stenosis
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Peter Rakovec, Matjaz Sinkovec,
Primoz Rode.
Department of Cardiology, University Medical Centre, Ljubljana, Slovenia
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Abstract
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The mechanism of syncope in aortic stenosis is
traditionally explained by reduced cerebral perfusion during exertion due to systemic
vasodilatation in the presence of a fixed cardiac output. It is also known that some cases
of syncope are caused by atrioventricular block or by serious ventricular arrhythmia, both
not being rare in this disease. Recent observations reveal another mechanism of exertional
syncope, ie neurocardiogenic (vasovagal) mechanism. Our cases with progressive bradycardia
and sinus arrest are described and discussed together with similar cases from the
literature. Increased left ventricular systolic wall stress and possibly ischaemia
represent a stimulus for cardiac mechanoreceptors, resulting in an exaggerated
cardio-inhibitory response.
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Key Words
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Syncope
aortic stenosis, vasodepressor response, cardioinhibitory response, R
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