Electrocardiograms, known as EKGs, can give your doctor a quick clue about life and death situations involving your cardiac health. The EKG is a diagnostic tool that represents the electrical activity that controls your heart. According to Medline Plus, an EKG can illustrate a myocardial infarction, or heart attack; ischemia, or angina; and irregular coronary rhythms.
Arrythmias
Arrythmias, or irregular heart rhythms, will show up as an abnormal EKG result. All EKGs measure the rate of your heartbeat by how many times per minute the heart contracts. A heart rate greater than 100 beats per minute is a tachycardia, or fast heart rate. Fevers, anxiety and even caffeine can show tachycardia on an EKG. Conversely, a very slow heartbeat of less than 60 beats per minute is bradycardia. Congestive heart failure, medications and a very strong heart can all elicit this abnormal result. Some arrythmias, including atrial fibrillation, will display an abnormal conduction between the chambers of your heart on the EKG.
Pacemakers
An implanted pacemaker will show abnormal EKG results, which are sometimes normal for that individual. For instance, a pacemaker is programmed to stimulate the heart to beat by either triggering the atria, ventricles or all four chambers of the heart. This electrical stimulation of the heart will reflect as abnormal on an EKG, producing a large spike each time the pacemaker fires.
Coronary Artery Disease
Coronary Artery Disease, or CAD, is a disease of the arteries that supply fresh oxygenated blood to keep the heart going. When these arteries are blocked or not functioning well, the EKG will represent either an active blockage, or heart attack, or an old blockage indicative of heart muscle damage. A cardiologist can tell if the abnormal EKG is representing decreased oxygenation of your heart indicative of angina, which could lead to future heart attacks.
Congenital Heart Defects
When someone is born with an imperfection of the heart, it's called a congenital heart defect. These defects, including problems with conduction in the heart and cardiomyopathy, will reflect abnormal EKG results. The physician can use the EKG reading to identify which parts of the heart are enlarged or working too hard. The American Heart Association says congenital heart defects are usually diagnosed in children, but sometimes these conditions will not be caught until later in life and can be exacerbated by weight gain, smoking or advancing age.
Electrolyte Imbalances
Electrolytes, including potassium, magnesium and calcium, are responsible for keeping your heart muscle beating. Electrolyte imbalances caused by illness, dehydration or overexertion will reflect as abnormal on an EKG. For example, a deficiency of potassium will show as a flattened or inverted waveform on part of your EKG. Your physician will interpret the EKG and treat the underlying reason for the electrolyte imbalance.
Heart Blocks
According to the American Heart Association, heart blocks represent failure of your heart chambers to conduct electricity properly. Heart blocks are congenital or develop later in life due to failure of the heart's electrical system, illicit drug use or prescription medications. First-, second- and third-degree heart block, with third degree being the deadliest, will all show very specific abnormal patterns on an EKG.
