Episodic syncope in hypertrophic cardiomyopathy:evidence for inappropriate vasodilation

Prasad, K, Williams, L, Campbell, R, Elliott, P M, McKenna, W J and Frenneaux, M (2008) Episodic syncope in hypertrophic cardiomyopathy:evidence for inappropriate vasodilation. Heart, 94 (10). pp. 1312-7. ISSN 1355-6037

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Abstract

Symptoms of impaired consciousness (syncope and pre-syncope) occur in 15-25% of patients with hypertrophic cardiomyopathy (HCM).1 In young patients a history of recurrent syncope is associated with an increased risk of sudden death.2(-)5 Syncope usually occurs without warning or symptoms suggestive of the cause. Detailed investigations identify a probable mechanism in a minority, usually paroxysmal atrial fibrillation or ventricular tachycardia. In the majority however no likely mechanism is found despite repeated 24-hour ambulatory echocardiography (ECG) or patient-activated monitoring, exercise testing and invasive electrophysiological studies.1 6 Empirical treatment with amiodarone, a pacemaker or an implantable cardioverter-defibrillator is commonly employed, but is often unsuccessful in relieving the symptoms. We have previously observed that approximately 30% of patients with HCM have abnormal blood pressure response during maximal upright exercise.7 8 This was due in the majority of patients to an exaggerated fall in systemic vascular resistance, possibly arising from abnormal activation of stretch-sensitive left ventricular mechanoreceptors,9 10 by a mechanism similar to that described in aortic stenosis.11 However, in some patients an inadequate cardiac output response to exercise may be responsible.12 We hypothesised that abnormal vasodepressor-mediated hypotension may also occur during daily life in patients with HCM, and that this may be an important mechanism of syncope when conventional investigations fail to reveal a cause.

Item Type: Article
Uncontrolled Keywords: adolescent,adult,blood pressure,cardiomyopathy, hypertrophic,dilatation, pathologic,exercise,humans,hypotension,pressoreceptors,syncope,tilt-table test
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 09 Mar 2015 07:28
Last Modified: 11 Jan 2019 15:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/52402
DOI: 10.1136/hrt.2008.141507

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