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

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

A cardiac cause of syncope has been associated with increased sudden death risk, whereas unexplained syncope has a benign prognosis. However, in patients who have depressed left ventricular function, the accuracy of diagnostic tests and the efficacy of therapy, such as antiarrhythmic drugs, are reduced. Previous studies of patients with syncope have not evaluated the contribution of left ventricular performance in risk stratification for sudden death. The purpose of our study of a large population of patients with syncope was to determine the impact of left ventricular dysfunction on sudden death risk if syncope is caused by a cardiac cause or remains unexplained after electrophysiologic testing. We retrospectively evaluated the relationship of left ventricular ejection fraction to sudden death prognosis in 88 consecutive patients referred for electrophysiologic testing to determine a cause of syncope. The mean age was 57 +/- 18 years, left ventricular ejection fraction was 0.41 +/- 0.20, and 66 patients (75%) had structural heart disease. In 49 patients (56%) a cardiac cause of syncope was diagnosed, and in 39 patients (44%) the cause of syncope remained unexplained after evaluation. Cardiac syncope was attributed to ventricular tachycardia in 27 patients, bradyarrhythmia in 11 patients, and supraventricular tachyarrhythmia in 11 patients. By logistic regression only structural heart disease was independently associated with cardiac cause of syncope (p = 0.003). After a mean follow-up of 790 +/- 688 days, nine patients had died suddenly, eight (89%) of whom had left ventricular ejection fraction less than 0.30.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prognosis after syncope: impact of left ventricular function. 841 7

Syncope is an abrupt and transient loss of consciousness caused by cerebral hypoperfusion. It accounts for 1% to 1.5% of emergency department visits, resulting in high hospital admission rates and significant medical costs. Syncope is classified as neurally mediated, cardiac, and orthostatic hypotension. Neurally mediated syncope is the most common type and has a benign course, whereas cardiac syncope is associated with increased morbidity and mortality. Patients with presyncope have similar prognoses to those with syncope and should undergo a similar evaluation. A standardized approach to syncope evaluation reduces hospital admissions and medical costs, and increases diagnostic accuracy. The initial assessment for all patients presenting with syncope includes a detailed history, physical examination, and electrocardiography. The initial evaluation may diagnose up to 50% of patients and allows immediate short-term risk stratification. Laboratory testing and neuroimaging have a low diagnostic yield and should be ordered only if clinically indicated. Several comparable clinical decision rules can be used to assess the short-term risk of death and the need for hospital admission. Low-risk patients with a single episode of syncope can often be reassured with no further investigation. High-risk patients with cardiovascular or structural heart disease, history concerning for arrhythmia, abnormal electrocardiographic findings, or severe comorbidities should be admitted to the hospital for further evaluation. In cases of unexplained syncope, provocative testing and prolonged electrocardiographic monitoring strategies can be diagnostic. The treatment of neurally mediated and orthostatic hypotension syncope is largely supportive, although severe cases may require pharmacotherapy. Cardiac syncope may require cardiac device placement or ablation.
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PMID:Syncope: Evaluation and Differential Diagnosis. 2829 Jun 47