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How Does An EKG Machine Work?

One of the most common tests for heart and other problems is the electrocardiogram, also known as an ECG or EKG. Its general purpose is to help doctors discover and treat cardiac problems by reading a patient’s heart rhythm.

It can read the rate and regularity of a heartbeat. The machine reads the size and position of the heart chambers and can perceive damage and implications of medications via irregularities in the heartbeat.

You can find EKG machines in cardiac wards, emergency rooms, doctor’s offices and ambulances. They are one of the most versatile machines and important for cardiovascular monitoring and diagnosis, but how exactly do they work?

The Parts of an EKG Machine

Aspects of the modern EKG machine have been around for decades, but despite many technological improvements, the machine itself is made for four primary components. Each of these work together to create diagnostics for the EKG.


The most recognizable part of the EKG machine is the electrodes. They are the small pads stuck to your body wires wires leading to the main EKG machine. There are two types of electrodes: bipolar and unipolar.

The bipolar electrodes go on the wrists and legs to measure the voltage differential. The unipolar electrodes can be placed on the arms and legs or the chest. They detect the heart rhythm and send that information to the EKG machine.

Lead Wires

The most troublesome part of an EKG machines are the primary lead wires that go from the electrodes to main EKG machine.  The wires carry the signal, but they can also become easily dislodged when moving around.

EKG lead wires often need replacing because of the constant use and wear and tear caused by movement.


When you play an electric guitar, the sound produced is faint and hard to understand. You can eliminate this by connecting an amplifier. It’s the same situation with an EKG machine.

The signals first go through the buffer and then transfer to the main amplifier. The buffer, which is part of the amplifier, stabilizes and translates the impulses. Once it gets to the amplifier, it increases the signal strength by a factor of 100. This allows the output to better read the impulses.

Processor and Output

It starts at the electrodes, goes through the wires and amplifier and ends up in the main processor and output. Traditional output entailed continuous paper printing, so doctors can see real time readouts of heart rhythm.

Printers are still used in many hospitals because of the cost savings and doctor’s like having something physical to go over. Technology has advanced where EKG machine output can be sent vie email, wireless to cell phones and more.

Doctors can see their patients EKG readout from home or at another hospital.

Types of EKG Machines

EKG machines come in a variety of sizes and capabilities. The most common EKG machines are the ones found in most hospitals and doctor’s offices known as an ambulatory EKG. It’s usually on a cart and can be taken from room to room and patient to patient.

It’s not like an X-ray or CT scan where you have to go to a special area to use it. They bring it to you. They have a wide array of capabilities, but they’re commonly used to help determine heart attacks, arrhythmia and other heart problems.

They provide a continuous readout of the patient. For people who don’t have readily diagnosable cardiac symptoms, they may go with a special machine that reads them while you’re out and about over several days.

This helps with problems that occur intermittently or during certain events like exercise, etc.

Portable EKG machines are similar to the ambulatory variety, but tend to me smaller and portable. You’ll see these in ambulances and other areas where space is an issue. They are smaller and tend to have fewer capabilities than they ambulatory counterpart.

Are You Considering an EKG Machine?

Cardiology Shop has a wide selection of EKG machines and EKG machine supplies from the industry’s best dealers. We have everything from portable EKGs to treadmills for cardiac stress tests. Check out our EKG machines here and let us know if we can help with anything.   

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