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post in: Products, Health Date:08 Oct 2017, 08:54 views:1272
Prinzmetal's or, prinzmetal angina ( /prntsmtl/, sounds like "prints metal (also known as variant angina, vasospastic angina (VSA angina inversa, or coronary vessel spasm ) is a syndrome typically consisting of angina (cardiac chest pain) at rest that nordsee occurs in cycles.
It is caused by vasospasm, a narrowing of the coronary arteries caused by contraction of the smooth muscle tissue in the vessel walls rather than directly by atherosclerosis (buildup of fatty plaque and hardening of the arteries). For a portion of patients Prinzmetal's angina may be a manifestation of vasospastic disorder and is associated with migraine, Raynaud's phenomenon or aspirin-induced asthma. 1, contents, signs and symptoms edit, in contrast to patient with unstable angina secondary to coronary atherosclerosis, patients with variant angina are generally younger and have fewer coronary risk factors (except smoking ).
Episode of chest pain usually does not progress from a period of chronic stable angina. Cardiac examination is usually normal in the absence of ischemia.
1, symptoms typically occur at rest, rather than on exertion (thus attacks usually occur in early morning hours). 2, two-thirds of patients have concurrent atherosclerosis of a major coronary artery, but this is often mild or not in proportion to the degree of symptoms. Prinzmetal's should be suspected by a cardiologist when the pain occurs at rest and/or in clusters, and in the absence of a positive treadmill stress test, as Prinzmetal's is exercise tolerant and can allergy generally only be diagnosed after other forms of cardiac disease have been.
It is associated with specific ECG changes allergy (elevation rather than depression of the ST segment ) together with small elevation of cardiac enzymes (especially with long attacks). However, in order to be diagnosed, these ECG changes can only be tracked when the electrocardiogram occurs while the patient is experiencing an attack. Therefore, many experts recommend provocative testing during electrocardiogram testing to attempt to induce an attack when Prinzmetal's is suspected.
Mechanism edit The mechanism that causes such intense vasospasm, as to cause a clinically significant narrowing of the coronary arteries is so far unknown, but there are three relevant hypotheses: Enhanced contractility of coronary vascular smooth muscle due to reduced nitric oxide bioavailability caused. 3 4 Acetylcholine is normally released by the parasympathetic nervous system (psns) at rest, and causes dilation of the coronary arteries.
5 While acetylcholine induces vasoconstriction of vascular smooth muscle cells through a direct mechanism, acetylcholine also stimulates endothelial cells to produce nitric oxide (NO). NO then diffuses out of the endothelial cells, stimulating relaxation of the nearby smooth muscle cells. In healthy arterial walls, the overall indirect relaxation induced by acetylcholine (via nitric oxide) is of greater effect than any contraction that is induced.
When the endothelium is dysfunctional, stimulation with acetylcholine will fail to produce, or produce very little, nitric oxide. Thus, acetylcholine released by the psns at rest will simply cause contraction of the vascular smooth muscle.
Thromboxane A2, a vasoconstrictor released by platelets to aid in clot formation, may also play a role in Prinzmetal's angina. Lipoprotein(a) interferes with fibrinolysis by competing with plasminogen.
The impaired fibrinolysis triggers thrombus formation, which also results in coronary vasospasm in variant angina.