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Acute coronary syndrome; Myocardial infarction
Angina is the primary symptom of coronary artery disease and, in severe cases, of a heart attack. It is typically experienced as chest pain and occurs when the heart muscle does not get as much blood (hence as much oxygen) as it needs for a given level of work (ischemia). Angina is usually referred to as one of two states:
The intensity of the pain does not always relate to the severity of the medical problem. Some people may feel a crushing pain from mild ischemia, while others might experience only mild discomfort from severe ischemia.
Angina itself is not a disease. Much evidence indicates that onset of angina less than 48 hours before a heart attack may be protective, possibly by conditioning the heart to resist the damage resulting from the attack. Angina may be experienced in different ways and can be mild, moderate, or severe.
Stable Angina. Stable angina is predictable chest pain. Although less serious than unstable angina, it can be extremely painful or uncomfortable. It is usually relieved by rest and responds well to medical treatment (typically nitroglycerin). Any event that increases oxygen demand can cause an angina attack. Some typical triggers include:
Angina attacks can occur at any time during the day, but most occur between 6 a.m. and noon.
Specific symptoms that are more likely to indicate angina include:
Other symptoms that may indicate angina or accompany the pain or pressure in the chest include:
Unstable angina is a much more serious situation and is often an intermediate stage between stable angina and a heart attack, in which an artery leading to the heart (a coronary artery) becomes completely blocked. A patient is usually diagnosed with unstable angina under one or more of the following conditions:
Unstable angina is now usually discussed as part of a condition called acute coronary syndrome (ACS). ACS also includes people with a condition called NSTEMI (non ST-segment elevation myocardial infarction) -- also referred to as non-Q wave heart attack. With NSTEMI, blood tests suggest a developing heart attack. These conditions are less severe than heart attacks but may develop into full-blown attacks without aggressive treatment. [For more information, see In-Depth Report #12: Heart attack and acute coronary syndrome.]
Doctors use a number of factors to help predict which patients with unstable angina or acute coronary syndrome are most at risk for developing a heart attack.
First, patients are categorized by whether they have a history of heart disease or risk factors for heart disease (such as diabetes, high blood pressure, and peripheral artery disease) or other complicating conditions (such as lung disease and heart failure). The doctor also evaluates the severity of the angina. Other factors that pose a high risk for ACS include:
Heart Attack. A full-blown heart attack occurs with severe damage to the heart, which blocks oxygen.
People with known heart disease and any unusual chest pain or other symptoms described above that do not clear up with medications should call 911. The degree of pain and the specific symptoms before a heart attack vary greatly among individuals. Symptoms can be abrupt, gradual, or intermittent. Some studies suggest that nearly half of patients with heart attack do not have chest pain as the primary symptom. Patients most likely to have atypical symptoms are women and the very elderly (although they can certainly have classic heart attack symptoms as well).
Symptoms That Are Less Likely to Indicate Angina or a Heart Attack. The following symptoms are less likely to be due to coronary artery disease:
However, the presence of these symptoms does not always rule out a serious heart event.
Prinzmetal's Angina. A third type of angina, called variant or Prinzmetal's angina, is caused by a spasm of a coronary artery. It almost always occurs when the patient is at rest. About two-thirds of people with it have severe atherosclerosis in at least one major blood vessel. Irregular heartbeats are common, but the pain is generally relieved immediately with standard treatment.
Silent Ischemia. Some people with severe coronary artery disease do not have angina pain. This condition is known as silent ischemia, which some experts attribute to the brain abnormally processing of heart pain. This is a dangerous condition because patients have no warning signs of heart disease. Some studies suggest that people with silent ischemia experience higher complication and mortality rates than those with angina pain.
Syndrome X. Syndrome X is a condition that occurs when patients have atypical angina chest pain. Their electrocardiograms are abnormal during a stress test, but they have no signs of blocked arteries. It is more likely to occur in women. Although it is unclear what causes this condition, imaging tests suggest that Syndrome X may also be caused by ischemia, as is angina.
Chest pain is a very common symptom in the emergency room, but heart problems account for only 10 - 33% of all episodes.
Other causes of chest pain or discomfort include:
Individuals who experience symptoms of a heart attack should take the following actions:
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE Jr, et al. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-Elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction) developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. J Am Coll Cardiol. 2007 Aug 14;50(7):e1-e157.
Antman EM. ST-Elevation myocardial infarcation: management. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Libby: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Saunders; 2007:chap 51.
Antman EM, Bennett JS, Daugherty A, Furberg C, Roberts H, Taubert KA. Use of nonsteroidal antiinflammatory drugs: an update for clinicians: a scientific statement from the American Heart Association. Circulation. 2007 Mar 27;115(12):1634-42. Epub 2007 Feb 26.
Antman EM, Hand M, Armstrong PW, Bates ER, Green LA, Halasyamani LK, Hochman JS, et al. 2007 Focused Update of the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: developed in collaboration With the Canadian Cardiovascular Society endorsed by the American Academy of Family Physicians: 2007 Writing Group to Review New Evidence and Update the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction, Writing on Behalf of the 2004 Writing Committee. Circulation. 2008 Jan 15;117(2):296-329. Epub 2007 Dec 10.
Assmus B, Honold J, Schachinger V, Britten MB, Fischer-Rasokat U, et al. Transcoronary transplantation of progenitor cells after myocardial infarction. N Engl J Med. 2006 Sep 21;355(12):1222-32.
Cannon CP and Braunwald E. Unstable angina and non-ST elevation myocardial infarction. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Libby: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Saunders; 2007:chap 53.
Chou R, Helfland M, Peterson K, Dana T, Roberts C. Comparative Effectiveness and Safety of Analgesics for Osteoarthritis. Comparative Effectiveness Review No. 4. (Prepared by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024.) Rockville, MD: Agency for Healthcare Quality and Research. September 2006.
Di Mario C, Dudek D, Piscione F, Mielecki W, Savonitto S, Murena E, et al. Immediate angioplasty versus standard therapy with rescue angioplasty after thrombolysis in the Combined Abciximab REteplase Stent Study in Acute Myocardial Infarction (CARESS-in-AMI): an open, prospective, randomised, multicentre trial. Lancet. 2008 Feb 16;371(9612):559-68.
Eisenstein EL, Anstrom KJ, Kong DF, Shaw LK, Tuttle RH, Mark DB, et al. Clopidogrel use and long-term clinical outcomes after drug-eluting stent implantation. JAMA. 2007 Jan 10;297(2):159-68. Epub 2006 Dec 5.
Gislason GH, Jacobsen S, Rasmussen JN, Rasmussen S, Buch P, Friberg J, et al. Risk of death or reinfarction associated with the use of selectivecyclooxygenase-2 inhibitors and nonselective nonsteroidal antiinflammatory drugs after acute myocardial infarction. Circulation. 2006 Jun 27;113(25):2906-13. Epub 2006 Jun 19.
Hirsch A, Windhausen F, Tijssen JG, Verheugt FW, Cornel JH, de Winter RJ; Invasive versus Conservative Treatment in Unstable coronary Syndromes (ICTUS) investigators. Long-term outcome after an early invasive versus selective invasive treatment strategy in patients with non-ST-elevation acute coronary syndrome and elevated cardiac troponin T (the ICTUS trial): a follow-up study. Lancet. 2007 Mar 10;369(9564):827-35.
Hulten E, Jackson JL, Douglas K, George S, Villines TC. The effect of early, intensive statin therapy on acute coronary syndrome: a meta-analysis of randomized controlled trials. Arch Intern Med. 2006 Sep 25;166(17):1814-21.
Hochman JS, Lamas GA, Buller CE, Dzavik V, Reynolds HR, Abramsky SJ, et al. Coronary intervention for persistent occlusion after myocardial infarction. N Engl J Med. 2006 Dec 7;355(23):2395-407. Epub 2006 Nov 14.
Hochman JS, Sleeper LA, Webb JG, Dzavik V, Buller CE, Aylward P, et al. Early revascularization and long-term survival in cardiogenic shock complicating acute myocardial infarction. JAMA. 2006 Jun 7;295(21):2511-5.
Kearney PM, Baigent C, Godwin J, Halls H, Emberson JR, Patrono C. Do selective cyclo-oxygenase-2 inhibitors and traditional non-steroidal anti-inflammatory drugs increase the risk of atherothrombosis? Meta-analysis of randomised trials. BMJ. 2006 Jun 3;332(7553):1302-8.
King SB 3rd, Smith SC Jr, Hirshfeld JW Jr, Jacobs AK, Morrison DA, Williams DO;et al. 2007 Focused Update of the ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: 2007 Writing Group to Review New Evidence and Update the ACC/AHA/SCAI 2005 Guideline Update for Percutaneous Coronary Intervention, Writing on Behalf of the 2005 Writing Committee. Circulation. 2008 Jan 15;117(2):261-95. Epub 2007 Dec 13.
Kostis WJ, Demissie K, Marcella SW, Shao YH, Wilson AC, Moreyra AE. Weekend versus weekday admission and mortality from myocardial infarction. N Engl J Med. 2007 Mar 15;356(11):1099-109.
Lloyd-Jones DM, Liu K, Tian L, Greenland P. Narrative review: Assessment of C-reactive protein in risk prediction for cardiovascular disease. Ann Intern Med. 2006 Jul 4;145(1):35-42.
Lunde K, Solheim S, Aakhus S, Arnesen H, Abdelnoor M, Egeland T, et al. Intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction. N Engl J Med. 2006 Sep 21;355(12):1199-209.
McGettigan P, Henry D. Cardiovascular risk and inhibition of cyclooxygenase: a systematic review of the observational studies of selective and nonselective inhibitors of cyclooxygenase2. JAMA. 2006 Oct 4;296(13):1633-44. Epub 2006 Sep 12.
Schachinger V, Erbs S, Elsasser A, Haberbosch W, Hambrecht R, Holschermann H, et al. Intracoronary bone marrow-derived progenitor cells in acute myocardial infarction. N Engl J Med. 2006 Sep 21;355(12):1210-21.
Spaulding C, Henry P, Teiger E, Beatt K, Bramucci E, Carrie D, et al. Sirolimus-eluting versus uncoated stents in acute myocardial infarction. N Engl J Med. 2006 Sep 14;355(11):1093-104.
Wang TJ, Gona P, Larson MG, Tofler GH, Levy D, Newton-Cheh C, et al. Multiple biomarkers for the prediction of first major cardiovascular events and death. N Engl J Med. 2006 Dec 21;355(25):2631-9.