Heart Attack, Myocardial Infarction or MI
Introduction:
Even though itwould appears that a heart attack should be straight forward and easy to recognize, this is not necessarily so. There is an atypical presentation of chest pain, which can also include abdominal pain symptoms, especially if a posterior wall MI or an inferior wall MI is present. Once a critical state has been reached with respect to the arteriosclerotic process affecting two or three coronary arteries, parts of the heart muscle will die off and be replaced with scar tissue.
There are several consequences from this: First, there is "pump failure" because the heart has no longer the full pumping power. Secondly, there is an immediate danger of irregular heart beats (arrhythmia) leading to cardiac fibrillation and death. This can be monitored for and treated with antiarrhythmic medication in the Coronary Care Unit of a hospital. Here is a link to a picture of a heart and the coronary arteries explaining a heart attack .
Symptoms:
The majority of patients will present with chest pain in the left chest area and there might be an acceleration of angina symptoms with chest and left arm pain. There is often a period of a few weeks to days before signs and symptoms of a heart attack develop, where the patient experiences fatigue, shortness of breath and pain behind the chest bone. When the actual heart attack hits, the chest pain is merely getting more pronounced, may feel like a crushing pain or like a piercing pain going right through into the back. Associated with this is often a left sided arm pain and jaw pain. There is a shortness of breath when there is pulmonary edema from congestive heart failure, also clammy skin and a there is a blue skin (the medical term for this is "cyanotic").
Not everybody presents this way. Women often present with atypical chest pain and up to 20% of people never have any chest pain. This atypical chest pain often presents with a different type of pain pattern, such as epigastric pain (mid upper abdomen), nausea and vomiting, particularly with an inferior wall MI. The phrenic nerve is not that far from the mediastinal space, which could explain the radiating pain into the diaphragm and upper abdominal area.
The important part for the family members or the people around the patient is to call 911 and indicate your suspicion that the person has a heart attack. The ambulance will soon arrive. Should the person pass out and get into shock it is important to apply CPR right away. The sooner CPR is applied, the better the chances of survival for the patient.
Diagnostic tests for heart attack
In the hospital the Emergency Room physician will assess the patient right away and do appropriate tests like an ECG, blood work for cardiac enzymes, start IV lines and give intravenous fluid. A cardiac monitor is applied to the skin right away as well which tells the physician whether there are any dangerous irregular heart beats developing.
Within a short period of time the cardiac enzymes will be reported back to the ER physician and indicate whether or not damage to the heart muscle has occurred. When in doubt, the cardiologist may want to do a stress test of the heart. This is an exercise test combined with ECG's before, during and after the test to see whether the oxygen supply to the heart muscle remains constant during exercise or whether it drops off. Here is a link showing an image of a patient doing an exercise stress test. If this test is not clearly positive, meaning that there are narrowed coronary arteries proven, this test can be more refined by doing a thallium stress test or the MIBI scan .
Treatment for heart attack:
It is important to treat this condition right away from the beginning due to arrhythmias, heart failure and hypotension, which could turn into cardiogenic shock and death due to the further closing of more coronary arteries.
Treatment therefore would include arrhythmia medications (Xylocaine and others), water pills (=diuretics), oxygen therapy and possibly thrombolytic therapy such as Streptokinase and others. A Swan- Ganz catheter might have to be placed in the right heart to measure pressures inside the heart and to be able to know exactly how much of each of the various specific heart medications to give. Obviously a cardiologist should supervise this kind of invasive, but often very successful therapy.
Only a few decades ago the overall mortality of people with heart attacks was about 60%. Now with good CPR initially and the Emergency Response Team being able to institute some of the therapy right at the scene and on the way to the hospital and with improved methods at the hospital the mortality rate has declined to 10 to 20 %. Obviously, the more the person neglected his/her health, the more serious the disease and the worse the mortality rate.
An early percutaneous (through the skin) transluminal (through the clot, but inside the lumen of the artery) cardiac angioplasty (=PTCA for short) can be as effective, if not more effective in the hands of an experienced cardiologist to open up the clogged coronary artery. PTCA has saved many lives as has CABG, an acronym for "coronary artery bypass graft". The cardiologist in consultation with a cardiovascular surgeon can judge what procedure is best suited for a particular patient.
What are some of the late complications following a heart attack? Within the first year following a heart attack about 10 % will develop a further heart attack as more stenotic lesions in the coronary arteries develop. Others will develop sudden irregular heart beats which sometimes can be life threatening and difficult to treat. Another complication is congestive heart failure which needs to be treated with angiotensin converting enzyme( ACE) inhibitors. All of these complications require an assessment by a cardiologist (Ref. 9, p. 1668).
|
