| name: | Heart Attack |
| also known as: | Myocardial Infarction; Acute Myocardial Infarction; AMI; Coronary; Coronary Thrombosis; Coronary Occlusion; MI; CK; CK-MB; CPK; Troponin I; Troponin T; Risk Stratification; ST-Segment Elevation; STEMI; ICD 410.90 |
| also see: | Cardiac Arrest; Angina; Acute Coronary Syndrome; Chest Pain; High Cholesterol; Hyperlipidemia; Angiogram; Angioplasty; CABG; ICD |
| description: | A heart attack or a myocardial infarction is when the heart has sustained varying degrees of injury, may even progress to a cardiac arrest, but is still beating and pumping. It results from interruption of coronary blood flow to the heart which includes partial or complete block of the coronary arteries that feed oxygenated blood to the heart itself. Blockage is usually by a thrombus off an atherosclerotic plaque, but can also be from spasm, blood clot, or an arrhythmia. Risk of heart attack is increased with smoking, stress, obesity, high cholesterol, hyperlipidemia, high blood pressure, diabetes, family history, sedentary life style, smoking, Type A personality, exercise in extreme of temperatures, cocaine. The four main clinical syndromes are: 1. Angina is when the heart is suffering a mild degree of lack of oxygen and exhibits this by causing pain. 2. Heart attack which is when there is an interruption of blood flow to a part of the heart resulting in heart tissue death, including ST-segment elevation (STEMI). 3. Heart attack without ST-segment elevation (NSTEMI), similar to unstable angina 4. Cardiac arrest is when the heart completely stops, no pumping and no beating. Once the heart stops, the person has from 3-5 minutes before death ensues. CPR can keep the brain and body oxygenated until the heart gets beating and pumping again. Acute Coronary Syndrome is a hybrid between and overlapping angina and heart attack. Risk stratification involves determining those patients who have low risk angina, high risk angina, unstable angina, or acute myocardial infarction syndrome, and the likelihood of progression, so that proper treatment options can be determined. Risk stratification is performed by angioplasty and/or heart perfusion scan. |
| signs & symptoms: | Includes chest pain, chest tightness, heavy squeezing crushing sensation, pain into the neck, jaw, and arm, feeling of impending doom, shortness of breath, sweating, nausea, vomiting, pallor, fainting, cough, high or low blood pressure, S4 heart sound. Persistent chest pain after adequate treatment can be due to a new heart attack, extension of an existing heart attack, pericarditis, and intestinal problems. Clinical pearl: heart attack in a diabetic might not be associated with chest pain. |
| diagnosis: | Based on signs, symptoms, history and exam. Perform the ABC of evaluation: Airway, Breathing, Circulation. If these are NOT present, it is a cardiac arrest. If the ABC are present, it is a heart attack, but a heart attack can progress into a cardiac arrest. Key diagnostic criteria for a heart attack include: 1. EKG showing ST segment elevation or depression, T wave inversion, and evolving Q waves. The Q-wave implies a transmural infarct with a totally obstructed infarct; the non Q-wave implies non-transmural with patent but narrow coronary artery. 2. cardiac enzymes, such as a CK-MB which is the specific cardiac enzyme elevated during the acute course of a heart attack. CK-MB rises about 6 hours into the infarction, and the diagnosis of a heart attack is either confirmed or rejected by 24 hours. Other isoenzymes that rise early in the evolution of an MI are troponin I and troponin T. LDH elevates at 24 hours and AST elevates at 2-3 days. Other studies might include an echocardiogram showing regional wall motion changes, an angiogram or an angioplasty. Often a heart scan is performed sometimes after a heart attack in order to assess damage, recovery, assess further risk. Differential diagnosis includes: angina, unstable angina, variant angina, aortic dissection, gastric ulcer, duodenal ulcer, heartburn, cholecystitis, pneumonia, pneumothorax, pulmonary embolism, costochondritis. |
| treatment: | If it is a cardiac arrest, begin CPR and dial 911. One person CPR is performed by giving two (2) breaths (mouth-to-mouth) followed by 15 chest compression (double hand palm down over the lower breast bone). Two person CPR is performed by giving one (1) breath (mouth to mouth) by person 1, followed by 5 chest compression by person 2. If it is a heart attack, dial 911. Heart attacks with STEMI are treated with oxygen, hospitalization, bed rest, as well as: 1. narcotic pain relievers, such as demerol or morphine 2. antiarrhythmia drugs depending upon the arrhythmia if any, and as also discussed under ACLS protocols, 3. blood thinners such as antiplatelet drugs notably aspirin plus clopidogrel (plavix), and possibly anticoagulation drugs such as heparin or enoxaparin (levenox), 4. possibly fibrinolytics such as alteplase, reteplase, or tenecteplase. Streptokinase is seldom used. 5. nitroglycerin also called nitrates which are a potent coronary artery dilators, such as nitroglycerin 6. digoxin to improve heart function, 7. beta blockers especially metoprolol to reduce the work of the heart and to decrease risk of V-fib 8. ACE inhibitors have been shown to be of benefit in improving heart function in patients with low ejection fractions. The most important drugs from the list above are narcotics, aspirin, nitroglycerin, and beta blockers. Monitor patient for potentially fatal arrhythmias such as vfib or vtach. Some patients might require an angioplasty or a CABG procedure. The angioplasty can be substituted for fibrinolytics in patients who have ST segment elevation (STEMI) only, who have a contraindication to taking fibrinolytics, and in whom the "door-to-balloon" within 90 minutes of hitting the hospital ER at a facility with PCI (percutaneous coronary intervention) can be achieved. Heart attack without STEMI or NSTEMIs are treated with oxygen, bed rest and: 1. narcotic pain relievers, such as demerol or morphine 2. nitroglycerin also called nitrates which are a potent coronary artery dilators, such as nitroglycerin 3. aspirin 4. beta blockers especially metoprolol 5. blood thinners such as antiplatelet drugs notably aspirin plus clopidogrel (plavix), and possibly anticoagulation drugs such as heparin or enoxaparin (levenox) 6. second line might include calcium channel blockers or ace inhibitors The EKG Q wave sometimes determines the severity of the heart attack and therefore can dictate treatment options: 1. non-Q wave heart attack: oxygen, nitroglycerin, antiplatelet drugs, anticoagulation drugs, beta blockers, and risk stratification. 2. Q wave heart attack: oxygen, nitroglycerin, antiplatelet drugs, anticoagulation drugs, beta blockers, plus fibrinolytics and angioplasty. Risk stratification only if patient suitable and stable. Clinical pearl: monitor patient for potential vfib Clinical pearl: rule out aortic dissection before giving anticoagulation drugs |
| prevention: | Lose weight, don't smoke, don't drink alcohol to excess and don't use drugs. Exercise, eat well, and treat any underlying medical condition as recommended by your doctor. |
| outcome: | If treated quickly, a heart attack victim can recover in 4-12 weeks. Unchecked or severe heart attack can result in heart arrhythmia, cardiomyopathy, pleural effusion, deep venous thrombosis, mitral regurgitation, ventricular septal defect, ruptured papillary heart muscle of the tricuspid valve leading to tricuspid regurgitation, arterial embolism stroke, ruptured heart, risk of future heart attacks, and death. Q wave heart attack has a higher initial mortality rate but non-Q wave heart attacks have a higher re-infarction rate. Killip mortality classification on prognosis: I - no CHF 5% II - mild-moderate CHF 10% III - severe CHF 30% IV - cardiogenic shock 80% |
skynetMD suggests the following:
| if: | If the person has had a cardiac arrest with no pulse, no heart beat, no breathing, begin CPR, and |
| go to: | Go to the phone and call 911 |
| if: | If the person is having a heart attack |
| go to: | Go to the phone and dial 911. |
| if: | If the person would like a heart condition Internet Resource |
| go to: | Go to American Heart Association www.americanheart.org, Heart Information Network www.heartinfo.org/ |
Last updated 2/7/2010