How Do Electrocardiogram Machines Work?

How Do Electrocardiogram Machines Work?

Electrocardiogram exam with machine and patient

Did you know that heart disease remains the number one cause of death in America? Over 800,000 Americans each year have a heart attack

This causes increased rates of mortality and disability. Electrocardiogram machines are useful in detecting cardiac conditions that can indicate a higher risk for heart disease. It is also the standard method for diagnosing heart attacks.

If you have an interest in learning more about how these machines work, then keep reading on. 

What Is an Electrocardiogram?

At its core – an electrocardiogram monitors the electrical signals from your heart. It does this by having someone attach various electrodes onto the torso region. As your heart pumps blood, the electrodes can pick up the signals. 

Some of the things that ECGs show are:

  • Irregular heartbeats
  • Heart attack
  • Size of your heart
  • Heart chambers
  • Heart damage

ECGs are useful in inpatient hospital settings. They are used for patients who have sudden complaints of chest pain, arrhythmias, or dizziness. Physicians give these tests for monitoring patients with ongoing cardiac diseases.

They are useful for patients who are at risk of developing a cardiac condition. Additionally, they are frequently used for monitoring a patient’s pacemaker which helps control the electrical component of your heartbeat and rate. 

If you have an upcoming surgery, a quick ECG can give your surgeon a good idea of your heart health. In return, this can pinpoint whether you are at a higher risk for undergoing general anesthesia. 

Electrocardiogram Test

How exactly does an ECG work? First off, if you do not have continuous symptoms, then a physician may recommend a Holter monitor. This can monitor your heart’s activity over the course of one to two days. 

It is portable and you can take it home. A standard ECG machine monitors the cardiac event as it is occurring. Twelve different leads are attached to your torso and upper or lower limbs. The patient should remove any jewelry and clothing on the upper torso at this time. 

The leads are then connected back to the monitor. You will likely be laying down for this test and you might have to shave patches of hair to ensure there is a good connection. 

You do not have to do anything while you receive the test. The ECG machine will monitor your heart for a certain amount of time and then the test is completed. 

Moving or touching the electrodes while the test is running may skew the results. It is important that the person lays completely still on the table for the most accurate measures.

The electrocardiogram test results will show your heart’s rhythm and alert the cardiologist to anything abnormal. If there are abnormal or inconclusive results, another test may be required. There could also be further follow-up tests through an echocardiogram.

Interpreting ECG Results

Clinicians interpret the results by comparing the print-out of the ECG to normal readings. The heart rhythm is what is shown in the reading.

It has three major parts:

  • P wave
  • QRS
  • T wave

The amplitude measures the height of each wave. For example, the average height of the P wave is between 2 to 2.5 mm tall. Practitioners measure this by the number of squares it reaches on the table.

In this example, it is 2.5 squares. Another common aspect of an ECG that health practitioners examine is the duration time. You can look at the P wave example again. 

The average length of time for the P wave is 0.06 to 0.12 seconds. If these results in the P wave are abnormal, it can indicate enlarged atriums. Each portion of the ECG gives indicators for what the problem might be. 

ECG vs Vital Sign Monitors

What is the difference between an ECG and other vital sign monitors? An electrocardiogram machine solely analyzes cardiac rhythms. It has higher sensitivity and accuracy than pulse or blood pressure checks. 

A typical vital sign monitor can assess a variety of different vitals including:

  • Oxygen saturation (SpO2)
  • Pulse rate
  • Respiratory rate
  • Blood pressure
  • End-tidal carbon dioxide (ETCO2)

Some of these machines can perform simple ECG readings, but it is largely used for monitoring the patient with other vital checks. It is not designed for addressing specific cardiac conditions on a regular basis.

Many times, inpatient facilities have a vital sign monitor and can bring in an ECG machine if needed.

Wearable Technology

Many people have taken to portable technology for monitoring their health. One study examined how accurate ECG readings on your watch or other portable device compare to ECG machines. 

The study mainly looked at the Apple Watch product. It has shown advertisements for helping with detecting atrial fibrillation through photoplethysmography (PPG). 

This technology works by using light sensors on the watch band that monitors changes in blood volume. It is considered a single lead ECG reading with Class II clearance by the FDA. 

This means that it should not be used as a definitive diagnosis. Instead, caution should be taken when using these readings for atrial fibrillation. A consultation with a medical practitioner is still advised. 

When used for detecting atrial fibrillation, the Apple Watch had a sensitivity of approximately 96% and a specificity of approximately 97%. The main concern with using wearable technology is false positives or negatives.

There is also a growing concern that people stop wearing it after a few months to a year. This poses a unique challenge when treating atrial fibrillation. This heart condition is a chronic disease and requires constant management. 

Since it is a single lead ECG, it also is not as accurate as 12-lead readings. 

12-Lead ECG Studies

Other studies have examined how physicians can more accurately interpret 12-lead ECG reports. Despite advances in technology, artificial intelligence is lacking in this area. 

One of the concerns with ECGs is a cardiologist interpreting the results. Artificial intelligence has started with one-lead ECG readings – you can find a prime example of this when you use your Apple Watch for a quick screening. 

These algorithms have not fully translated to 12-lead readings at this time. This study examined the use of technology in interpreting 12-lead ECG results. 

Oftentimes, the ECG can show more than one cardiac condition. However, most cardiologist reports only classify one disease such as atrial fibrillation. 

The researchers found that automated systems produced fairly accurate results for the diagnosis of cardiac conditions. Ultimately, the researchers hoped that there will eventually be a larger, open-source database for ECG images.

This study shows that the future of cardiology and diagnosing conditions comes from high-quality ECG readings. 

Some electrocardiograms are already providing ECG interpretation software. These are some of the best machines on the marketplace as they can help cardiologists determine diagnoses. 

It gives a broader database for the comparison of normal and abnormal rhythms. It can also store this information and ECG readings so that you can transfer it between facilities or to other units. 

Multi-Uses of ECGs

Electrocardiograms are not solely used in cardiology clinics. They have a broad range of uses from critical units to outpatient clinics. They are also used in end-of-life care. 

ECGs are necessary in ICUs, but they can easily lead to delayed response times by nurses and practitioners. This is due to the alarm system that most ECGs are ingrained with. 

Researchers and health practitioners have dubbed this “alarm fatigue.” How do you combat this? 

ECG machines are designed for extremely sensitive monitoring. This means that not all of the alarms are likely needed in every type of setting. In end-of-life care, researchers found that only 11 out of the 151 alarms were indicative of atrial fibrillation. 

However, almost three-quarters of the alarms were audible and required the nurse or health care worker to come into the room. In this particular setting, the goal is comfort care for the patient and the family.

While audible alarms for minor changes in ECG may be necessary for intensive care units, it is not likely necessary in this setting. This points to the need for having ECG units with adaptable settings. 

It is important that you purchase ECGs that can adapt to patients, settings, and diagnoses. For example, the frequency and detection ranges are different for a pediatric patient than an adult patient.

Rather than purchasing multiple types of ECGs, having one that can do it all is more cost-friendly and efficient for your health facility. 

Best Electrocardiogram Machine

You have already heard the differences, advantages, and disadvantages of a 12-lead versus a single-lead ECG. There are many other types of ECG machines on the market. 

Other common ones include a 2-lead and 6-lead ECG machine. A 6-lead ECG reading is arguably the next closest thing to a 12-lead. 

Recent studies have found that it is more accurate than your Apple Watch, but it doesn’t quite compare to the tried-and-true method. Instead, it is more likely used for bringing awareness to cardiovascular conditions and self-monitoring. 

If you want definitive diagnoses then a 12-lead is still the best electrocardiogram machine. 

Buy Electrocardiogram Machines

Electrocardiogram machines are essential in a healthcare facility. They can give practitioners a brief insight into a patient’s cardiac and general health.

A 12-lead ECG is the most widely used machine in facilities and provides highly accurate results. Contact us today and let one of our representatives talk with you about purchasing ECG machines for your facility.


Electrocardiogram exam with machine and patient


More Equipment Topics

What is a Capnograph?

Purpose & Definition A capnograph is a medical device that rapidly measures respiratory health to assist health care providers to respond sooner when patients are not breathing normally.  It measures

Read More »

EKG Machines: How Do They Work?

For those who work in cardiology, EKG machines are life saving pieces of equipment, helping to diagnose and treat countless heart conditions every year. But what exactly are they? One

Read More »

Subscribe to Our Newsletter

Stay informed with the latest information from Infinium Medical.