myocardial infarction (MI)
, also known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing
damage to the heart muscle.[1] The most common symptom is chest pain or discomfort which may
travel into the shoulder, arm, back, neck or jaw.[1] Often it occurs in the center or left side of the chest
and lasts for more than a few minutes.[1] The discomfort may occasionally feel like heartburn.[1] Other
symptoms may include shortness of breath, nausea, feeling faint, a cold sweat or feeling tired.[1] About
30% of people have atypical symptoms.[8] Women more often present without chest pain and instead
have neck pain, arm pain or feel tired.[11] Among those over 75 years old, about 5% have had an MI
with little or no history of symptoms.[12] An MI may cause heart failure, an irregular heartbeat,
cardiogenic shock or cardiac arrest.[3][4]
Most MIs occur due to coronary artery disease.[3] Risk factors include high blood pressure, smoking,
diabetes, lack of exercise, obesity, high blood cholesterol, poor diet and excessive alcohol intake.[5][6]
The complete blockage of a coronary artery caused by a rupture of an atherosclerotic plaque is usually
the underlying mechanism.[3] They are less commonly caused by coronary artery spasms, which may be
due to cocaine, significant emotional stress and extreme cold, among others.[13][14] A number of tests
are useful to help with diagnosis, including electrocardiograms (ECGs), blood tests, and coronary
angiography.[7] An ECG, which is a recording of the heart's electrical activity, may confirm an occlusion
myocardial infarction (OMI) if an ST elevation MI (STEMI) or STEMI equivalent is present.[8][15][16]
Commonly used blood tests include troponin and less often creatine kinase MB.[7]
Treatment of an MI is time-critical.[17] Aspirin is an appropriate immediate treatment for a suspected
MI.[9] Nitroglycerin or opioids may be used to help with chest pain; however, they do not improve
overall outcomes.[8][9] Supplemental oxygen is recommended in those with low oxygen levels or
shortness of breath.[9] In a STEMI, treatments attempt to restore blood flow to the heart and include
percutaneous coronary intervention (PCI), where the arteries are pushed open and may be stented, or
thrombolysis, where the blockage is removed using medications.[8] People who have a non-ST elevation
myocardial infarction (NSTEMI) are often managed with the blood thinner heparin, with the additional
use of PCI in those at high risk.[9] In people with blockages of multiple coronary arteries and diabetes,
coronary artery bypass surgery (CABG) may be recommended rather than angioplasty.[18] After an MI,
lifestyle modifications, along with long-term treatment with aspirin, beta blockers and statins, are
typically recommended.[8]
Worldwide, about 15.9 million myocardial infarctions occurred in 2015.[10] More than 3 million people
had an ST elevation MI, and more than 4 million had an NSTEMI.[19] STEMIs occur about twice as often
in men as women.[20] About one million people have an MI each year in the United States.[3] In the
developed world, the risk of death in those who have had an STEMI is about 10%.[8] Rates of MI for a
, also known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing
damage to the heart muscle.[1] The most common symptom is chest pain or discomfort which may
travel into the shoulder, arm, back, neck or jaw.[1] Often it occurs in the center or left side of the chest
and lasts for more than a few minutes.[1] The discomfort may occasionally feel like heartburn.[1] Other
symptoms may include shortness of breath, nausea, feeling faint, a cold sweat or feeling tired.[1] About
30% of people have atypical symptoms.[8] Women more often present without chest pain and instead
have neck pain, arm pain or feel tired.[11] Among those over 75 years old, about 5% have had an MI
with little or no history of symptoms.[12] An MI may cause heart failure, an irregular heartbeat,
cardiogenic shock or cardiac arrest.[3][4]
Most MIs occur due to coronary artery disease.[3] Risk factors include high blood pressure, smoking,
diabetes, lack of exercise, obesity, high blood cholesterol, poor diet and excessive alcohol intake.[5][6]
The complete blockage of a coronary artery caused by a rupture of an atherosclerotic plaque is usually
the underlying mechanism.[3] They are less commonly caused by coronary artery spasms, which may be
due to cocaine, significant emotional stress and extreme cold, among others.[13][14] A number of tests
are useful to help with diagnosis, including electrocardiograms (ECGs), blood tests, and coronary
angiography.[7] An ECG, which is a recording of the heart's electrical activity, may confirm an occlusion
myocardial infarction (OMI) if an ST elevation MI (STEMI) or STEMI equivalent is present.[8][15][16]
Commonly used blood tests include troponin and less often creatine kinase MB.[7]
Treatment of an MI is time-critical.[17] Aspirin is an appropriate immediate treatment for a suspected
MI.[9] Nitroglycerin or opioids may be used to help with chest pain; however, they do not improve
overall outcomes.[8][9] Supplemental oxygen is recommended in those with low oxygen levels or
shortness of breath.[9] In a STEMI, treatments attempt to restore blood flow to the heart and include
percutaneous coronary intervention (PCI), where the arteries are pushed open and may be stented, or
thrombolysis, where the blockage is removed using medications.[8] People who have a non-ST elevation
myocardial infarction (NSTEMI) are often managed with the blood thinner heparin, with the additional
use of PCI in those at high risk.[9] In people with blockages of multiple coronary arteries and diabetes,
coronary artery bypass surgery (CABG) may be recommended rather than angioplasty.[18] After an MI,
lifestyle modifications, along with long-term treatment with aspirin, beta blockers and statins, are
typically recommended.[8]
Worldwide, about 15.9 million myocardial infarctions occurred in 2015.[10] More than 3 million people
had an ST elevation MI, and more than 4 million had an NSTEMI.[19] STEMIs occur about twice as often
in men as women.[20] About one million people have an MI each year in the United States.[3] In the
developed world, the risk of death in those who have had an STEMI is about 10%.[8] Rates of MI for a
