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| {{Chronic stable angina}} | | __NOTOC__ |
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| {{CMG}} | | {{CMG}} |
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| ''The terms '''Syndrome X''' or '''Metabolic syndrome X''' may also be referring to [[metabolic syndrome]].''
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| '''''Synonyms and key words:''''' Microvascular angina
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| ==Overview== | | ==Overview== |
| '''(Cardiac) syndrome X''' is [[Angina pectoris|angina]] (chest pain) associated with objective evidence of myocardial ischemia in the absence of epicardial [[coronary artery disease]]. The disorder has been hypothesized to be a disorder of the coronary microvasculature rather than the large caliber epicardial coronary arteries.
| | Syndrome X may refer to [[cardiac syndrome X]], [[metabolic syndrome]] and single X syndrome, where an individual has a single X chromosome, typically described as [[Turner syndrome]]. The otherwise unidentifiable rare disease afflicting [[Brooke Greenberg]] and only about half a dozen other people in the world. |
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| ==Pathophysiology==
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| In a large percentage of patients, there is microvascular dysfunction. Specifically, the microvasculature cannot dilate to accomadate increased blood flow during exertion to meet the needs of myocardial metabolism. Syndrome X has been associated with [[dysautonomias]] and may be an extension of abnormalities of the autonomic nervous system. It has also been hypothesized by some physicians that patients with Syndrome X have "enhanced pain sensitivity". It has also been speculated that although the coronary arteriogram may appear normal, there may in fact be diffuse atherosclerosis present in what has been termed "a female pattern" of disease.
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| ==Epidemiology and Demographics==
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| Syndrome X occurs more often in young women. Some studies have found an increased risk of other vasospastic disorders in syndrome X patients, such as [[migraine]] and [[Raynaud's phenomenon]].
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| ==Natural history, complications, and prognosis==
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| Syndrome X does not appear to be associated with an excess of major coronary events.
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| ==Risk Factors==
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| Female gender and [[left ventricular hypertrophy]] are associated with an excess risk of Syndrome X. The onset in women often occurs after [[menopause]].
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| ==Other Conditions to Distinguish Syndrome X From==
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| Syndrome X should be distinguished from [[Prinzmetal's angina]], a disorder which involves spasm of the main epicardial coronary arteries. Syndrome X involves dysfunction of the downstream microvasculature. Syndrome X must also be distinguished from [[esophageal spasm]].
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| ==Diagnosis==
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| Syndrome X is a diagnosis of exclusion. The diagnostic criteria are as follows:
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| *There must be evidence of [[myocardial ischemia]]: Diagnostic studies include an exercise [[ECG]], [[stress scintigraphy]], or [[stress echocardiography]] in conjunction with anginal chest discomfort.
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| * [[Angina pectoris|Angina]]: Angina pectoris must be present. The angina pectoris associated with Syndrome X may last longer that the anginal discomfort associated with the fixed epicardial stenoses of atherosclerotic heart disease.
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| * Abnormal [[Cardiac stress test]]: ST changes are typically similar to those of [[coronary artery disease]] and opposite of those with [[Prinzmetal's angina]]. Myocardial perfusion imaging can be abnormal in 30% of patients.
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| * [[Coronary angiogram]]: There is no narrowing of the epicardial arteries. However, Syndrome X may be associated with a reduction in coronary [[vasodilator reserve]] presumably due to abnormalities in the [[coronary microcirculation]]. During stress, sampling of the [[coronary sinus]] demonstrates the production of [[lactate]] by the [[myocardium]]. Intracoronary [[acetylcholine]] can be administered to evaluate endothelium-dependent [[coronary flow reserve]].
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| ===ESC Guidelines for investigation in patients with Syndrome X (DO NOT EDIT)<ref name="pmid16735367">{{cite journal| author=Fox K, Garcia MA, Ardissino D, Buszman P, Camici PG, Crea F et al.| title=Guidelines on the management of stable angina pectoris: executive summary: The Task Force on the Management of Stable Angina Pectoris of the European Society of Cardiology. | journal=Eur Heart J | year= 2006 | volume= 27 | issue= 11 | pages= 1341-81 | pmid=16735367 | doi=10.1093/eurheartj/ehl001 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16735367 }} </ref>===
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| {{cquote|
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| ===Class I===
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| '''1.''' [[Chronic stable angina echocardiography|Resting echocardiogram]] in patients with angina and normal or non-obstructed coronary arteries to assess for presence of ventricular hypertrophy and/or [[diastolic dysfunction]]. ''(Level of Evidence: C)''
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| ===Class IIb===
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| '''1.''' Intracoronary acetylcholine during coronary arteriography, if the arteriogram is visually normal, to assess endothelium-dependent coronary flow reserve, and exclude [[vasospasm]]. ''(Level of Evidence: C)''
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| '''2.''' Intracoronary ultrasound, coronary flow reserve, or FFR measurement to exclude missed obstructive lesions, if angiographic appearances are suggestive of a nonobstructive lesion rather than completely normal, and stress imaging techniques identify an extensive area of [[ischaemia]]. ''(Level of Evidence: C)''}}
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| ==Treatment==
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| The mainstay of treatment in patients with Syndrome X are [[calcium channel blocker]]s, such as [[nifedipine]] and [[diltiazem]]. Other therapies include:
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| *[[Nitrates]]
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| *[[Beta blockers]]
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| *[[Aminophylline]] - may be effective via inhibition of adenosine receptors.
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| *[[Estrogen]] - may be effective in women.
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| ===ESC Guidelines for pharmacological therapy to improve symptoms in patients with Syndrome X (DO NOT EDIT)<ref name="pmid16735367">{{cite journal| author=Fox K, Garcia MA, Ardissino D, Buszman P, Camici PG, Crea F et al.| title=Guidelines on the management of stable angina pectoris: executive summary: The Task Force on the Management of Stable Angina Pectoris of the European Society of Cardiology. | journal=Eur Heart J | year= 2006 | volume= 27 | issue= 11 | pages= 1341-81 | pmid=16735367 | doi=10.1093/eurheartj/ehl001 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16735367 }} </ref>===
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| {{cquote|
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| ===Class I===
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| '''1.''' Therapy with [[nitrates]], [[beta blockers]], and [[calcium channel blockers]] alone or in combination. ''(Level of Evidence: B)''
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| '''2.''' [[Statin]] therapy in patients with [[hyperlipidaemia]]. ''(Level of Evidence: B)''
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| '''3.''' [[ACE inhibitors]] in patients with [[hypertension]]. ''(Level of Evidence: C)''
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| ===Class IIa===
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| '''1.''' Trial of therapy with other anti-anginals including nicorandil and metabolic agents. ''(Level of Evidence: C)''
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| ===Class IIb===
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| '''1.''' [[Aminophylline]] for continued pain, despite Class I measures. ''(Level of Evidence: C)''
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| '''2.''' Imipramine for continued pain, despite Class I measures. ''(Level of Evidence: C)''}}
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| ==References== | | ==References== |
| {{reflist|2}} | | {{reflist|2}} |
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| ==Review Articles==
| | {{WH}} |
| *[http://heartdisease.about.com/cs/coronarydisease/a/CSX.htm Cardiac Syndrome X]
| | {{WS}} |
| *[http://www.texasheartinstitute.org/HIC/Topics/Cond/CardiacSyndromeX.cfm Texas Heart Institute]
| | [[Category:Disease]] |
| *[http://content.nejm.org/cgi/content/full/347/17/1377 New England Journal of Medicine Editorials]
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| {{Circulatory system pathology}} | |
| {{SIB}} | |
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| [[Category:Ailments of unknown etiology]] | |
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Disease state]]
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| [[Category:Ischemic heart disease]]
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| [[Category:Mature chapter]]
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