An EKG, also known as an electrocardiogram or ECG, is a recording of the electrical impulses made by the heart as it contracts. In a conventional EKG, there are 12 “leads” placed on the body. Each lead detects the electrical impulses of the heart from different directions. The combination of these 12 waveforms make up the EKG.

What does it measure?

The simplest function of an EKG is to measure your heart rate and rhythm. It helps detect whether the heart is beating too fast or slow, if the rhythm is irregular, and if there are extra beats or skipped beats.

On top of that, the EKG can also give us some information about the sizes of the different chambers of the heart and if the walls of the heart are getting good or poor blood flow (which is important in how we diagnose a heart attack). Finally, we can see if certain electrolyte levels in your body are abnormal and if you’re having severe side effects from certain medications.

A “normal EKG” usually has the following:

1. Heart rate between 60 and 100 beats per minute
2. Regular, consistent rhythm (known as sinus rhythm)
3. Normal waveform height and orientation
4. Normal blood flow to all the walls of the heart
5. No skipped or extra beats

As you can see, there are a lot of factors that need to go right in order to have a “normal EKG.” If any of those factors in your EKG deviates from normal, the automated interpretation of your EKG will say “abnormal.”

Some abnormal EKGs can have major implications. It can indicate anything from a heart attack, to atrial fibrillation, to dangerously high potassium levels in the blood. On the other hand, there are many times when the abnormalities detected are not necessarily clinically significant and may have no long-term effect on your heart.

Common “Abnormal EKGs” Findings

• Left (or Right) Axis Deviation
• Left (or Right) Bundle Branch Block
• Intraventricular Conduction Delay
• Left Anterior (or Posterior) Fascicular Block
• 1^st Degree AV Block
• Premature Atrial (or Ventricular) Contractions
• Low Voltage
• Voltage criteria for Left Ventricular Hypertrophy
• Left (or Right) Atrial Enlargement
• Paced Rhythm

All of these diagnoses are abnormal findings on an EKG and can have important implications in certain situations. But they also need to be taken in the proper context. It is especially important to consider what type of symptoms you’ve been having.  That’s why it’s always important to go over your findings with your cardiologist.

An ECG is an important tool in cardiology, but it is one of many tools. If your provider thinks your ECG shows findings that are important in your particular situation, they will take whatever next steps are felt to be necessary.  

Dr. Chinedu (ChiChi) Madu is a general cardiologist with Virginia Heart who sees patients in the Arlington and Alexandria Offices.