An electrocardiogram (EKG) measures your heart’s electrical activity. This noninvasive test can measure many things, from how fast the heart beats, to how well the heart’s chambers are conducting electrical energy.
An abnormal EKG can mean many things. Sometimes EKG abnormalities are a normal variation of a heart’s rhythm, which does not affect your health. Other times, an abnormal EKG can signal a medical emergency, such as a myocardial infarction (heart attack) or a dangerous arrhythmia. A doctor or medical professional trained in reading EKGs can interpret the readings to determine if you need further treatments.
An EKG machine is typically a portable machine that has 12 “leads” or long, flexible tubes attached to sticky electrodes. These are placed on designated areas around the heart and on the arms and legs. These electrodes sense the electrical impulses coming from multiple directions. Undergoing an EKG procedure isn’t painful. You don’t have to do anything special to prepare for the test. The test itself typically takes five minutes or less.
The EKG machine doesn’t generate electricity. Instead, it conducts and measures electrical activity. Typically, the heart conducts electricity in a standard pathway: first from the right atrium to the left atrium. The current then goes to the atrioventricular (AV) node, which signals the ventricles to contract. The current then flows to an area known as the bundle of His. This area divides into fibers that provide current to the left and right ventricles.
Any disruption in this current can affect the heart’s ability to work well. Ideally, an EKG can measure any potential disruptions.
Because an EKG measures so many different aspects of the heart’s function, there are multiple results an EKG can signify, including:
- Defects or abnormalities in the heart’s shape and size. An abnormal EKG can signal that one or more aspects of the heart’s walls are larger than another. This can signal that the heart is working harder than normal to pump blood.
- Electrolyte imbalances. Electrolytes are electricity-conducting particles in the body that help to keep the heart in rhythm. Potassium, calcium, and magnesium are electrolytes. If your electrolytes are imbalanced, you may have an abnormal EKG reading.
- Heart attack or ischemia. During a heart attack, blood flow is affected in the heart, and heart tissue can begin to lose oxygen and die. This tissue will not conduct electricity as well, which can cause an abnormal EKG. Ischemia, or lack of blood flow, may also cause an abnormal EKG.
- Heart rate abnormalities. A typical human heart rate is between 60 and 100 beats per minute. An EKG can determine if the heart is beating too fast or too slow.
- Heart rhythm abnormalities. A heart typically beats in a steady rhythm. An EKG can reveal if the heart is beating out of rhythm or sequence.
- Medication side effects. Taking certain medications can impact a heart’s rate and rhythm. Sometimes, medications given to improve the heart’s rhythm can have the reverse effect and cause arrhythmias. Examples of medication that affect heart rhythm include beta blockers, sodium channel blockers, and calcium channel blockers.
Several symptoms can indicate that you may need an EKG to determine if your heart is functioning normally.
Seek emergency medical attention if you experience:
- chest pain/discomfort
- difficulty breathing
- heart palpitations — you may physically feel your heart beating oddly
- feeling as if you might pass out
- feeling as if your heart is racing
- feeling like your chest is being squeezed
- sudden weakness
Treatment response to an abnormal EKG will typically depend upon the underlying cause. For example, some people experience a very slow heartbeat where the heart is not conducting electrical signals in the correct order. This person may require a pacemaker, which helps to restore the heart to a more normal rhythm.
Other people may require medications taken regularly to maintain a more normal heart rhythm.
People who are experiencing a heart attack may require cardiac catheterization or surgery to allow for blood flow to return to the heart.
People with electrolyte imbalances may require correction with medications or fluids. For example, a dehydrated person may have imbalanced electrolytes that are causing an abnormal EKG. This person may require fluids, electrolyte-containing beverages, or medicines to restore electrolytes.
Sometimes, a doctor may not recommend any treatments for an abnormal EKG if a person is not experiencing troublesome symptoms or if the abnormality is not cause for concern.