The test used to measure the heart’s electrical activity, the electrocardiogram, often causes confusion because two different acronyms, EKG and ECG, describe the exact same procedure. An electrocardiogram is a fundamental, non-invasive diagnostic tool that captures the tiny electrical signals generated by the heart muscle. This electrical map provides a view of the heart’s function, helping to identify various underlying health conditions.
EKG and ECG Are the Same Test
The terms ECG and EKG refer to the identical medical examination: the electrocardiogram. ECG is the abbreviation derived from the English and Latin roots: Electrocardiogram. The alternative acronym, EKG, originates from the German spelling, Elektrokardiogramm.
The German term was popularized in the early 1900s by the Dutch physiologist Willem Einthoven. Some medical communities, particularly in the United States, adopted EKG to avoid confusion with the abbreviation EEG, which stands for electroencephalogram (a test of brain electrical activity).
Understanding the Electrocardiogram Procedure
An electrocardiogram is a quick and painless test that involves attaching small, sticky sensors called electrodes to the patient’s skin. Typically, ten electrodes are placed on the limbs and across specific points on the chest to capture the heart’s electrical field from multiple perspectives. These electrodes act as receivers to detect the natural electrical impulses generated by the heart; they do not send electricity into the body.
The electrodes are connected by wires to the recording machine, called an electrocardiograph, which amplifies these minute signals. The machine compares the electrical activity detected between different pairs of electrodes, which are known as “leads.” A standard test, the 12-lead ECG, records the heart’s activity from twelve different angles or viewpoints.
These twelve perspectives provide a comprehensive view of the heart’s electrical conduction system. The machine translates the voltage differences into a continuous, wavy line tracing on paper or a digital screen. This tracing is a time-based graph that the clinician uses for diagnostic analysis.
What Electrical Signals Reveal About Heart Health
The resulting graph translates the heart’s electrical process into a readable waveform. Healthcare providers analyze the timing, amplitude, and shape of these waves to diagnose a range of cardiac conditions. The tracing is composed of distinct deflections: the P wave, the QRS complex, and the T wave, which represent the sequential activation and recovery of the heart chambers.
The P wave signifies the electrical activation of the heart’s upper chambers, the atria, causing them to contract. The QRS complex follows, representing the electrical impulse spreading through the lower chambers, the ventricles, triggering their contraction to pump blood.
The T wave shows the electrical recovery, or repolarization, of the ventricles as they relax and prepare for the next beat. The time intervals between these waves can reveal an irregular heart rhythm, known as an arrhythmia. Analysis of segments between the waves, such as the ST segment, is used to detect signs of damage to the heart muscle, such as a heart attack or inadequate blood flow (ischemia).