Diagnosing a heart attack: Putting it all together
Heart Smart Talk
Over the past few weeks we have been discussing the signs of a heart attack or blocked coronary arteries and some of the tests that can be used to confirm the diagnosis. So let’s put it all together. Before we do that, let’s review some key terms.
WHAT IS A HEART ATTACK?
A heart attack is sudden blockage of the coronary arteries (that bring blood to the heart), usually caused by break-up of plaque inside the artery and formation of a clot which blocks off the blood flow to a portion of heart muscle suddenly.
This usually leads to chest pain, but may not cause chest pain in all circumstances, especially in older people, women and diabetics. In this population, a heart attack may only give shortness of breath, dizzy feeling, nausea and or vomiting, and sometimes stomach pain – commonly mistaken for “gas”.
In some cases, particularly diabetics, there may not be any symptoms and will manifest itself on an electrocardiogram (ECG) done for routine check or for some other reason (incidental finding).
This is a medical emergency and treatment must be given within six to 12 hours from when the symptoms start for the best outcome.
WHAT IS ANGINA?
Angina is the medical term for chest pain believed to be due to a blocked coronary artery. Angina may be further defined as stable or unstable.
Stable angina: This is usually chest pain (or shortness of breath) brought on by some physical activity (such a brisk walking, running, climbing stairs or hill) and the pain goes away after resting or using a medication called nitroglycerine.
This usually indicates that there is build-up of plaque inside the coronary arteries and the plaque has caused at least 70 per cent blockage to the flow of blood to the heart. Usually at rest there are no symptoms, but once the work of the heart increases with exercise, the blocked artery cannot relax and increase blood flow to match the increased demand for oxygen and nutrients created by the physical activity.
This is a warning sign the body has devised to let us know that something is wrong. Pay attention!
Stable angina does not usually need an emergency room visit or hospitalisation, but the doctor will usually refer you to a cardiologist or internist for further evaluation and treatment.
Unstable angina: Chest pain which used to occur with exertion is not occurring at rest, or with minimal activity. This is usually an indication that the plaque has broken up and a heart attack is impending. It is usually difficult to distinguish between a heart attack and unstable angina at the outset. So usually, unstable angina is treated exactly like a heart attack, until additional tests are done to exclude a heart attack.
SO SHOW UP TO THE EMERGENCY ROOM WITH CHEST PAIN, THEN WHAT?
You will be seen right away or as soon as possible — bearing in mind other emergencies such as trauma etc. We know that time is of the essence. The medical team will get an ECG as soon as possible and have your “vital signs” — blood pressure, heart rate, oxygen level, temperature — checked and a doctor will go through your symptoms quickly, while reviewing your ECG. At this point the doctor will decide if your ECG shows signs of a heart attack.
In up to 40 per cent of cases the ECG can be perfectly normal, even when you are having a heart attack, so the doctor may decide to keep you for further testing, even if your ECG is normal. After reviewing your ECG, you will fall into one of two categories
1. Significant changes on ECG suggesting complete sudden blockage of one coronary artery: This usually needs a strong clot-buster medication called “thrombolytic” to break up the clot and prevent permanent heart muscle damage or emergency coronary angiogram (specialised X-ray to show the coronary arteries) — with a view to open up the blockages (angioplasty) or refer for coronary artery bypass, depending on what the angiogram shows.
There is a very narrow window to either give the clot-buster or do the angioplasty that will prevent permanent heart damage. That is six to 12 hours. This is why we strongly recommend that if you have any chest pain that is lasting more than 20 minutes, and you are over 40 years old and have any of the risk factors for coronary artery disease (cigarette smoking, hypertension, diabetes, high cholesterol, family history of early coronary artery disease), that you get help and go to the emergency room as soon as possible. We have a saying that time is muscle. The longer it takes for you to get treatment, the more likely it is that the heart muscle will be permanently damaged. Usually after 12 hours of blockage, the damage is permanent and is one of the most common reasons leading to heart failure.
2. Minimal or no changes on the ECG: This could be either a less severe form of heart attack or unstable angina. The doctor won’t be able to tell the difference right away, but you will be admitted and treatment started for a heart attack while additional tests are run to detect damage to the heart muscle. This will require a minimum of 48 hours of hospitalisation and observation. During this time the doctor will review your risk and the likelihood of a significant high-risk blockage. Based on this risk assessment, the doctor may decide to treat you with medication alone or refer you for an urgent coronary angiogram (within that hospital stay). This is with a view to open any blockages with angioplasty or refer to by-pass surgery.
WHAT HAPPENS DURING THE HOSPITAL STAY?
After a heart attack or unstable angina, you would usually be in hospital for an average of two to six days, sometimes longer, depending on whether there are any complicating issues such as heart failure or infections. During this time the doctor will start you on medication aimed at lowering your cholesterol, treating your blood pressure and diabetes, if you have those.
During this time, too, you will get advice on diet and exercise and be referred to a dietician and physiotherapy for cardiac rehabilitation. There is also discharge planning for your care once you are discharged from the hospital, and review of all your medication as well as education on your medication and your medical condition.
Dr Claudine Lewis is an adult cardiologist and medical director at Heart Smart Centre in Montego Bay. She is also a cardiologist at the Cornwall Regional Hospital and an associate lecturer with the University of The West Indies. Questions may be sent to email@example.com and for additional information call 684-9989 or visit the website www.heartsmartcentre.com