Electrocardiogram (ECG) machines are commonly used pieces of medical equipment that measure and record electrical activity in the heart. Interpreting results from an ECG reading allows physicians to diagnose a variety of heart conditions.
An ECG is generally recommended for people who have a variety of symptoms, including chest pain, abnormal heart beat (arrhythmias), shortness of breath, nausea, weakness, palpitations, anxiety, abdominal pain or fainting. Physicians will also recommended an ECG for people over 40 years old or those with a family history of heart disease.
ECG machines provide a relatively simple medical procedure lasting approximately 30 minutes. Adhesive electrodes are placed in a pattern across a patient's chest, arms and legs with lead wires connecting them directly to the ECG machine. This medical equipment then records several heartbeats on a sheet of graph paper in a series of graph-like tracings or waves. Each heartbeat consists of a P wave, QRS complex, ST segment, T wave and U waves. The shapes of the waves that ECG machines report reveal abnormalities in heart anatomy or function.
A normal ECG reading shows flat dips in between the contracting and relaxing of the heart. It is considered to be an abnormal ECG reading when there's an absence of flat dips. An abnormal ECG reading can indicate a more serious problem. Common diagnoses are: enlarged or inflamed heart, heart muscle defects, valve or artery disease and heart attacks. If an abnormal ECG reading occurs, physicians generally recommend further testing on other ECG machines or medical equipment to confirm results.
Not all abnormal ECG readings are cause for concern. Sometimes events of low blood sugar or muscle contractions produce false readings on ECG machines. However, it is important that if a patient experiences an abnormal ECG reading, they maintain a copy of their results for future comparison.
In other instances, a patient may be experiencing symptoms that cannot be captured on regular ECG machines. These patients may be sent home with an ambulatory electrocardiography device to attempt to capture an accurate ECG reading. This portable piece of medical equipment, called a Holter monitor, is used for continuous monitoring of the heart's electrical activity over an extended period. For patients with more transient symptoms, a cardiac event monitor may also be used over the course of a month or more to capture an accurate ECG reading.