This is what you like to see
An abnormal ECG is not equivalent to a heart attack. That’s only one of the many, many things which will cause your report to read “abnormal ECG”
ECG Important General Principals
ECG EKG GENERAL PRINCIPALS: keep these in mind before you read your report:
- If you have unexplained chest pain call 911 even if your ECG is normal.
- Abnormal usually does not mean “heart attack.” If it looks like a big heart attack it will say, in bold or capital letters, “STEMI.”
- A “normal ECG” is what is normal for most people. Some completely healthy hearts have patterns that the computer will call abnormal.
- Many things which are not directly related to the heart can cause an abnormal EKG. Electrolyte abnormalities (low or high potassium, calcium, sodium), brain strokes, many medications, lung abnormalities, to name but a few.
- Sometimes the best piece of information is a previous EKG. If your new EKG is unchanged it is very reassuring. The computer interpretation may include a comparison to a previous reading if it is in the computer database.
- On the other hand, the EKG computer can miss subtle abnormalities, including some which indicate a heart attack. THE EKG CAN BE NORMAL EARLY IN A HEART ATTACK. If you have chest pain, seek help.
- BOTTOM LINE: It takes an experienced ECG reader AND knowledge of the patient’s symptoms and history to determine the meaning of the ECG. This is often more important for decision-making than the computer reading.
WHAT IS THE ECG MEASURING?
The heart is a muscle but it is divided into different parts, called chambers. Each one is really a different pump. In order to keep the blood flowing most efficiently in the correct direction, each chamber must be pumped in the correct timing sequence. To do this the heart has an “electrical” system, called the conduction system. The ECG reports the timing and direction of “electricity” through this system.
WHAT IS THE ECG LOOKING FOR?
The EKG gives a lot of information. These are a few of the important things your health providers are looking at:
- The heart rate
- Whether the electrical pathway, which keeps the heart beating in an orderly fashion, is working correctly.
- Help determine if someone having chest pain is having a heart attack or a heart artery blockage.
- If the heart has been strained or thickened by high blood pressure.
- Toxic effects of medications on heart electrical conduction.
- Impending complications from electrolyte abnormalities.
READING THE ECG REPORT
Of the list of numbers seen on the left side, the only one you should concern yourself with is the “Vent rate.” This is how fast the bottom part of your heart, the big blood-pumping ventricles, are beating. It is the same number you would get if you checked your wrist pulse, in most cases.
The interpretation on our example ECG is shown in the right column.
- The top line tells the rhythm: In this case normal sinus rhythm. Sinus is the normal pathway for electricity.
- “Normal sinus rhythm,” tells you that the heart rate is between 60-100.
- Most people focus immediately on the bottom line, which hopefully reads “normal EKG.”
- But don’t freak out if it says “abnormal EKG.” The computer will read this if anything is “abnormal,” even if it’s simply that your heart rate is fast because you have a fever or are nervous, or slow because you are in great condition and relaxed.
- All of the other information you may find on the right-hand column describes specific abnormalities.
- While the computer is pretty good at detecting heart attacks and some other serious problems, it is not perfect. Most importantly, it doesn’t know anything about you, except perhaps your age and gender. Interpreting the meaning of an EKG truly requires knowledge about the patient’s condition, complaint, and medications: the clinical context.
ECG VOCABULARY
The ECG computer, like its human counterparts, isn’t always sure of what to make of things. It may imply a level of uncertainty. You may see the following modifiers:
- “Nonspecific” means what it says. It’s not normal (or typical of most people) but it doesn’t clearly indicate a particular problem, such as a heart artery blockage. The report will still be considered abnormal or the interpretation may read “nonspecific ECG.”
- “Can not exclude,” or “consider,” or “possible,” mean there is a hint that some finding is present, but it doesn’t quite meet the criteria. The ECG will still be labeled abnormal.
- The final interpretation may be “Normal ECG,” “Abnormal ECG,” “Non-Specific ECG” or “Borderline ECG.
HERE ARE A FEW COMMON FINDINGS REPORTED ON THE ECG
- SINUS ARRHYTHMIA- This is completely normal with no clinical importance. The heart rate normally fluctuates with breathing in and out. Some people fluctuate a little more than average, this is sinus arrhythmia.
- ISCHEMIA: This means part of your heart may not be getting enough blood due to a blocked artery. Many things can look like ischemia which are not from a blocked artery.
- STEMI- that is a full-blown heart attack
- TACHYCARDIA- any heart rate faster than 100
- BRADYCARDIA- any heart rate slower than 60.
- ATRIAL FIBRILLATION- a very common abnormal heart rhythm
- PREMATURE ATRIAL CONTRACTION (PAC)- this is an extra beat coming from the top part of your heart. Common in normal healthy hearts and a common cause of palpitations.
- PREMATURE VENTRICULAR CONTRACTION (PVC)- This is an extra beat coming from the bottom chambers of your heart.
- RIGHT BUNDLE BRANCH BLOCK- This means the electricity is slow getting to the right side of the heart. It is seen in up to 2% of normal healthy young people in which case it is a normal variant. Its presence does not correlate with heart attacks or artery blockages. It may develop later in life due to the conduction system “wearing out” or due to sudden or chronic stress on the right side of the heart.
- INCOMPLETE RIGHT BUNDLE BRANCH BLOCK- Present in more than 10% of normal healthy young people. In most cases, this can be ignored, it is a normal variant.
- LEFT BUNDLE BRANCH BLOCK- This occurs when the electricity is slow getting to the left side of the heart. This is present in less than 1% of young healthy hearts. Otherwise, it should raise concern for coronary artery disease and conduction system abnormalities.