Which Signals Are Measured by an EKG Machine?
Little more than a century ago, measuring the heart’s electrical signals to diagnose health issues was a distant concept. But ever since the electrocardiogram (EKG machine) was invented, doctors have been able to measure these signals by comparing their relative voltage to those of a healthy heart. This type of measurement is only possible because the body is able to conduct electricity and EKG machines are designed to pick up these signals.
By attaching electrodes to the surface of the body in specific areas, EKG machines can pick up the electrical signals that represent various phases of the heart’s rhythm. The first pulse that is measured is called the P wave, which picks up the electrical signal generated by the sinotrial node, or pacemaker, of the heart. The second and largest signal is the QRS complex, which represents the relaxing of the atria, followed by the contraction of the ventricles. Finally, the T wave measures the repolarization of the ventricles. Each of these signals can be studied independently or in concert with the others to detect a variety of cardiac issues.
The data generated by EKG machines can help doctors detect several problems related the heart’s function. These include the heart rate, the presence of hypertension, the heart’s chemical balance, damage to certain areas of the heart, and arrhythmias. Additionally, by looking at a depression between the S and T waves, EKGs can observe and diagnose an arterial obstruction. EKG machines known as Holter monitors are designed to make these detections.
An electrocardiogram test is often performed for the first time at a physician’s office as part of a routine physical work-up, but it is more commonly seen in the field of cardiology. While other forms of cardiac testing have been introduced in the past several decades, the EKG machine is still heavily relied upon throughout the medical community.
