Prinzmetal angina

Prinzmetal angina Definition

This medical disorder is characterized by periodic cardiac chest pain and tightness. Medical experts describe this condition as “unstable angina” since it occurs only at rest and does not have a predictable pattern. The ailment commonly occurs in females. It is also called by other names like:

  • Variant angina

  • Angina inversa

  • Prinzmetal-Massumi syndrome

  • Prinzmetal’s variant of angina pectori

Prinzmetal angina Symptoms

The symptoms normally commence at night and rarely occur when a patient is in motion. Interestingly, this type of angina occurs almost at the same time of the day on a regular basis and lasts for 5 to 30 minutes. Most patients suffer from atherosclerosis in which a major coronary artery thickens due to accumulation of fatty substances such as cholesterol. However, this is less pronounced than other signs of the disorder, which includes:

  • Intense crushing pain behind the breast bone

  • Squeezing sensation

  • Pressure in the chest region

  • Pain radiating from the chest to the neck, jaw, shoulder, or arms

  • Loss of consciousness

Prinzmetal angina Causes

Variant angina is solely caused by coronary artery spasm, an involuntary constriction of one of the vessels that supply the cardiac muscles with oxygenated blood. This condition decreases the width of the artery and deprives the heart muscles of blood and oxygen, triggering severe chest discomfort. Prolonged pain can transform into a cardiac attack if ignored. A sudden spasm of the coronary arteries has been attributed to an unknown problem arising in the endothelium, the thin layer that lines the interior surface of these blood vessels. Parasympathetic nervous system, a part of the autonomic nervous system originating in the brain stem and the lower portion of the spinal cord, releases acetylcholine under normal circumstances to dilate the coronary arteries. The neurotransmitter not only causes vasoconstriction of vascular smooth muscle cells, but is also responsible for stimulating the endothelial cells to secrete nitric oxide (NO). The chemical gas gradually seeps through the endothelial cells and invokes relaxation of the adjacent smooth muscle cells. As long as the lining of the arteries function properly, acetylcholine can successfully aid in the relaxation of the arteries. However, a damaged endothelium fails to respond to the neurotransmitter and impairs the release of the artery-widening nitric oxide. The end result is a constricted vascular smooth muscle, which manifests into angina.

A potent hypertensive agent as well as a vasoconstrictor called thromboxane can trigger angina inversa while facilitating platelet aggregation. Certain lipoproteins can severely impair fibrinolysis, which is carried out to prevent the blood clots from growing by interfering with plasminogen, an inactive precursor of the enzyme plasmin. Formation of a thrombus inside the coronary artery produces an arterial spasm. Key research studies have showed that an unstable angina is also caused by factors like:

  • Migraine

  • Cardiac syndrome X

  • Raynaud’s phenomenon

  • Emotional stress

  • Non-prescribed medications

  • Drug abuse

  • Extreme cold

Prinzmetal angina Diagnosis

It is important to note that cardiac enzymes such as creatine kinase (CK), aspartate aminotransferase (AST), troponin I or T and lactate dehydrogenase (LDH) are of variable specificity to the muscles of the heart. These are the typical markers for the diagnosis of myocardial injury. However, elevated levels of cardiac enzymes may not always signify damaged arteries. Elevation of the ST-segment on an electrocardiogram indicates coronary artery vasospasm in the absence of high grade stenosis. Another method typically used by cardiac specialists is thallium scintigraphy in which certain amount of thallium-201 is injected into the body followed by production of a 2-D image of the diseased heart filled with the radioisotope. However, coronary angiography remains the mainstay for diagnosis of variant angina. The exact location and severity of an arterial spasm can be easily detected using this technique. Here, a small catheter is inserted through the skin into an artery in the groin or the arm. Under the guidance of a fluoroscope, an instrument with a fluorescent screen used for viewing X-ray images, the catheter is then advanced to the opening of the affected coronary arteries. A small quantity of radiographic contrast is then injected into each coronary artery. The images that are obtained after the completion of the test clearly reveal the extent and severity of all coronary arterial spasms. In order to determine the extent of the condition, a provocation study could be done in which the patients are exposed to a chemical agent such as ergonovine, methylergonovine or acetylcholine to provoke a response. The entire diagnostic procedure is generally performed with the use of local anesthesia.

Prinzmetal angina Treatment

Administration of medications like nitroglycerin (NG) and calcium channel blockers can easily widen or open the blood vessels and facilitate proper flow of oxygenated blood to the cardiac muscles. Doctors may prescribe a different class of calcium channel blockers in case a patient does not respond well to previous medicines. Some sufferers are advised to take alpha blockers that help in lowering blood pressure and increasing the width of constricted blood vessels by negating the effects of stress hormones like cortisol and norepinephrine. NG in the form of sprays and tablets are used to treat the frequent episodes of angina. The pharmaceutical agent can reduce the spasm and alleviate pain, hence used as a preventive medication. It is also available as extended-release capsules that usually provide instant relief. Long-acting nitrates as potent drugs have resolved many cases of unstable angina by decreasing coronary vasoconstriction.

Prinzmetal angina Prognosis

In all likelihood, the severity of coronary artery disease predicts the outcome of the patients. Most cases have been successfully treated with a high survival rate.

Prinzmetal angina Complications

Failure to treat the condition in time can lead to cardiac arrhythmias or heart attacks that may permanently damage the coronary arteries.

Prinzmetal angina is a life-threatening disorder that needs timely check-up and treatment. Since smoking and drinking increases the risk of coronary artery spasms, a change in lifestyle is absolutely necessary.

References

http://en.wikipedia.org/wiki/Prinzmetal’s_angina

http://heartdisease.about.com/od/chestpainangina/a/prinzmetal.htm

http://emedicine.medscape.com/article/153943-overview

http://www.whonamedit.com/synd.cfm/3059.html

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