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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eighteen volunteers with a mean age of 63.3 years, who were asymptomatic and without significant heart disease, were investigated with standard electrophysiological tests, performed before and after inhibition of autonomous neural tone with propranolol (0.1 mg . kg-1) and atropine (0.02 mg . kg-1). In addition heart rate responses to maximal exercise, carotid sinus pressure and bolus injection of isoprenaline (0.01 microgram . kg-1) were studied to evaluate the relation between different functional qualities of the cardiac conduction system. Autonomous tone inhibition (ATI) caused significant reductions in the mean PP-interval, sinus code recovery time (SNRT) and corrected sinus node recovery time (CSNRT). Furthermore, the precision of CSNRT determinations increased after ATI. In contrast, the AV-node effective refractory period and conduction time (AH-interval) did not change after ATI. A significant correlation existed between CSNRT and heart rate after ATI, both variables reflecting sinus node automaticity, while no covariation was found between CSNRT and the response to isoprenaline stimulation. AV-node refractoriness and conduction time showed covariation after, but not before, autonomous inhibition. As elderly asymptomatic non-patients were examined the use of the presented group characteristics as reference values for diagnostic investigations is suggested. For example pre-drug CSNRT above 545 ms (mean + 2 SD) or above 505 ms after ATI, indicates impaired sinus node automaticity.
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PMID:Autonomous influence on sinus node and AV node function in the elderly without significant heart disease: assessment with electrophysiological and autonomic tests. 742 68

Syncope is a symptom of a wide variety of underlying disorders. As such, it is a common and challenging clinical problem with different pathophysiologic mechanisms and prognostic implications. The clinical spectrum of etiologies of syncope includes disorders classified as cardiovascular, noncardiovascular and unexplained. Generally, in patients in whom an initial diagnosis can be made, in the majority this is usually accomplished by a detailed history and thorough physical examination, that includes orthostatic vital signs and carotid sinus pressure. In the remaining cases, that can be as many as 50% of patients, the objective of subsequent noninvasive evaluation is to diagnose the cause of syncope, but also to stratify the patients in those with and those without underlying structural heart disease, and selectively apply additional more specialized or invasive tests. Cardiac syncope, and particularly when ventricular tachycardia is the cause, has the worst prognosis with 20 to 30% one-year mortality. This realization prompts rigorous effort in diagnosing or excluding an arrhythmic cause and applying aggressive therapy in such high risk patients. Thus, if after conventional noninvasive testing the etiology of syncope remains elusive in patients with underlying structural heart disease, electrophysiologic studies should be performed. Electrophysiologic studies identify a potential cause in up to two thirds of these patients. Treatment based on electrophysiologic diagnoses is effective in preventing syncope recurrences but may also reduce cardiac mortality. In patients without structural heart disease, head-up tilt testing has been very useful in diagnosing neurally mediated syncope and guiding its therapy. Finally in patients with recurrent syncope which remains unexplained despite extensive testing, a loop monitor may record the rhythm during an episode and provide or exclude a diagnosis. The discussion in this article serves as a brief overview of the clinical spectrum of syncope and describes a stepwise and systematic approach to diagnosis of this common, albeit challenging, medical problem, with emphasis on recent developments in the syncope work-up.
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PMID:The clinical spectrum and diagnosis of syncope. 833 Aug 49

Surgical treatment of functional single-ventricle heart disease with a modified Fontan procedure results in elevated central venous pressure. The case report describes a 19-year-old boy with hypoplastic left heart syndrome and Fontan palliation that resulted in frequent debilitating headaches after transcatheter closure of systemic venous-to-pulmonary venous collaterals. Measured increased intracranial pressure and prompt relief of the headaches with lumbar puncture favored a diagnosis of pseudotumor cerebri. After implantation of a lumboperitoneal shunt, the patient's headaches improved dramatically. Headaches are frequent in patients with Fontan circulation. The current literature supports a pivotal role of elevated dural venous sinus pressure in the pathogenesis of pseudotumor cerebri. The high superior and inferior vena caval pressures characteristic of modified Fontan anatomy may account for headaches in some of these patients.
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PMID:Pseudotumor cerebri associated with modified Fontan anatomy. 2289 38