Glossary
Starting with A for "ACE inhibitor" and continuing through to Y for "Yolk Sac Tumour", we give you succinct explanations for scientific and medical terms in clear and simple words.
- Myocardial infarctionalso known as heart muscle infarction
Death of tissue in a region of the heart muscle. A myocardial infarction is an acute complication of inadequate perfusion of the coronary arteries, which is mostly already present.
Causes
Continuous critically deficient perfusion of the coronary arteries when the previous perfusion has also bee inadequate (coronary insufficiency). Alternatively continuous spasm of the coronary vessels. Myocardial infarction frequently occurs during or after physical or psychological stress. It is the result of an increase in the oxygen requirement of heart muscle or of an cute interruption of perfusion, particularly when the blood vessels are hardened and constricted (arteriosclerosis) and a coronary artery is occluded by a blood clot.
Symptoms
Severe feeling of pressure behind the breastbone, with chest pains and spreading pain, like that in angina pectoris, but usually more intense. The pain is mostly accompanied by anxiety and the fear of destruction. Frequent symptoms include low blood pressure, rapid and low pulse, pallor and cold sweat, nausea and sometimes vomiting.
Diagnosis
1. On the basis of the symptoms; 2. Electrocardiography (ECG); 3. Detection in the blood of raised concentrations of enzymes which are specific to heart muscle; 4. Increases in the blood concentrations of the muscle proteins troponin T and troponin I; 5. other laboratory tests include increased erythrocyte sedimentation rate, increased concentrations of blood platelets and raised blood sugar.
Therapy
1. First Aid: Pain is reduced with analgesics and with nitroglycerin, which also widens blood vessels (see organic nitrates). Acetylsalicylic acid inhibits platelet aggregation and heparin inhibits blood aggregation. If there are no contraindications and the infarction has occurred less than 6 hours previously, the blood clot should be dissolved as soon as possible or the occluded coronary vessel expanded with a balloon catheter. 2. After the acute therapy has been completed, a heart catheter investigation (coronary angiography) is carried out to assess further therapeutic possibilities. If the course is complicated the catheterisation can be carried out earlier.
Glossary entries: Roche and Walter de Gruyter, Berlin