An abnormal electrocardiogram reading can result from an electrolyte imbalance, medication side effects or a heart attack, according to Healthline. Abnormalities in the heart rate, rhythm, shape and size are additional reasons for abnormal electrocardiogram readings.
Electrolytes impact electrocardiogram results because electrolytes are particles that conduct electricity and help keep the heart in rhythm, notes Healthline. Electrolytes include magnesium, potassium and calcium.
A heart attack influences EKG results because a heart attack impacts blood flow, and that may cause heart tissue to lose oxygen and die, explains Healthline. As a result, the tissue is a poor conductor of electricity, and that causes abnormal EKG results. An abnormal EKG reading can also be the result of lack of blood flow, or ischemia.
Relative to abnormalities in the size and shape of the heart, an abnormal EKG may indicate that one of the heart's walls is bigger than the others, reports Healthline. An EKG can signal whether a heart beats faster or slower than the average of 60 to 100 beats per minute.
An EKG can also identify if a heart beats outside of its normal rhythm, notes Healthline.com. The types of medication that impact heart rhythm include calcium channel blockers, sodium channel blockers and beta blockers.