Stress testing
Besides the 12-lead resting ECG, an ECG can be obtained during exercise and nuclear stress tests. The following sections examine exercise stress tests and nuclear stress tests.
Exercise stress test
An exercise stress test records the ECG while the patient is exercising. The patient either walks on a treadmill with an incline or uses an exercise bike. During the test, a continual ECG is recorded, and the blood pressure is monitored.
The test may be ordered for these reasons:
- The patient is starting an exercise program.
- The patient has angina that is getting worse.
- To evaluate the patient’s heart after an angioplasty or bypass surgery.
- To evaluate heart rhythm changes with the stress of exercise.
Preparation for the test includes the following:
- The patient should wear clothes and shoes for exercising.
- The provider will indicate what daily medications should be taken prior to the test.
- The patient should not take a dose of Viagra, Cialis, or Levitra for erectile dysfunction 48 hours before a stress test.
- The patient should not smoke or consume caffeine or alcohol 3 hours before the test.
- The patient signs a consent form prior to the test.
Here is what occurs during the test:
- Electrodes and lead wires will be placed on the patient. A blood pressure cuff will be applied to the patient’s arm.
- The patient will begin to exercise slowly, and gradually the exercise difficulty will increase.
- The provider should always be present during the test. If the patient has chest discomfort, dizziness, palpitations, or shortness of breath, the test will stop. Emergency supplies or a crash cart should be kept nearby in case of an emergency.
Remote ECG monitoring
With the advances in technology, several types of remote ECG monitoring can be used for patient care. The following sections discuss types of remote ECG monitoring that can be used.
Holter monitor
A Holter monitor is used to monitor the heart over a 24- to 48-hour period while patients go about their normal activities. Sometimes patients experience a heart issue that cannot be picked up on a resting 12-lead ECG. Having a longer monitoring period can capture the abnormalities.
When placing electrodes for a Holter monitor, consult the users’ guide. There are many configurations for electrode placement. Different monitors use varying numbers of electrodes. Holter monitors typically use three to seven chest electrodes. As with the resting 12-lead ECG, lead wires attach the electrodes to the small Holter monitor. The monitor runs on batteries and is small enough to fit into a pocket.
The following are patient education points for a Holter monitor test:
- Wear the monitor continuously. The monitor will be removed during your appointment in 24 to 48 hours.
- While wearing the Holter monitor, avoid metal detectors, large magnets, high-voltage areas, x-rays, and electric blankets. Do not get the monitor wet (e.g., no bathing, showering, or swimming).
- Keep a detailed journal of the symptoms experienced. These symptoms could include chest pain, shortness of breath, palpitations or changes in the heartbeat, dizziness, or fainting. Document the date, time, symptoms experienced, and the activity being done at the time. (Many facilities provide patients with a journal for the documentation.)
- During the return visit, the provider will look at the tracing for abnormalities. The journal of timed activities will help the provider identify what is occurring.
- The patient is instructed on what to do if the electrodes or lead wires fall off.
- The patient is instructed on who to contact with questions or if problems occur.
Cardiac event recorder
The cardiac event recorder is a portable, battery-powered ECG device. The recorder is activated by the patient when symptoms occur, and it records the ECG. Patients may wear a cardiac event recorder for 30 days. When symptoms occur only occasionally, it is difficult to capture the abnormality on a resting 12-lead ECG or a Holter monitor. The patient may also be asked to keep a journal, as with the Holter monitor. With the cardiac event recorder, patients go about their daily activities. The monitor can be removed during bathing and showering or swimming.
When patients experience symptoms, they push the recorder’s activation button. An ECG is recorded and stored. The ECG can be sent to the provider via a phone or other technology. A provider will review the tracing. If there is an emergency, the patient will be called and told to go to the nearest emergency department.
There are two types of cardiac event recorders, and the key difference between them is whether the stored ECG includes the moments before the symptom started:
- Looping memory monitor (also called a cardiac loop recorder): A pager-sized monitor connected to two chest electrodes by wires. It continuously records the ECG and overwrites old data as it goes, so it is always capturing the most recent activity. When the patient activates it after symptoms begin, it saves the ECG from just before, during, and shortly after the event - it stores the pre-symptom ECG.
- Symptom event monitor (also called a post-event monitor): A handheld or wrist-worn device with small metal disks on the back that act as electrodes. The patient places it on the chest and activates it only once symptoms are felt, so it records and stores the ECG starting from that point - it does not store the pre-symptom ECG.
Implantable loop recorder
The implantable loop recorder (also called a loop recorder implant) is a small recorder (under 2 inches) that looks like a flash drive. It is surgically implanted just under the skin in the upper left chest. It can be implanted in an ambulatory care facility.
Often the device is used for patients who have episodes of fainting, seizures, and palpitations, and other ECG tests have not been able to detect the abnormality. It also catches infrequent arrhythmias that can be missed with traditional ECG monitoring.
The device continuously records the ECG for 2 to 3 years. It records the ECG if the heart rate falls below or rises above the preset limits (set by the provider). The patient can also record the ECG if symptoms are experienced. The provider can download the saved ECG data at the next appointment.
Transtelephonic monitoring
A transtelephonic monitor (TTM) is a small device that records a patient’s ECG when the patient pushes the activation button. The TTM has four electrodes on the back of the device that can record a single lead. The ECG data is sent via phone to the base station at the provider’s office. The signal is converted to a readable tracing that can be displayed on a monitor or printed out. There are two types of TTMs:
- TTM with internal memory: The ECG is recorded and stored when the patient pushes a button. The data can be transmitted by phone to the provider. This type of TTM is used for patients with infrequent arrhythmias.
- TTM with no internal memory: The TTM is placed over the heart, and the phone receiver is placed over the TTM. Once the activation button is pushed, the TTM records and immediately sends the live ECG to the provider via the phone line. The data is not saved on the device. This type of TTM is used for patients with pacemakers and internal cardioverter-defibrillators. It allows the provider to monitor the patient remotely.
Portable handheld ECG monitors
There are a variety of portable handheld ECG monitors on the market. Many produce a single lead. The ECG data can then be transferred to other devices using software, Bluetooth, smartphones, or USB ports. These devices are marketed to be used at home. A person can use the device and save ECG tracings. The tracings can then be reviewed by the person’s provider at the next visit. The machines work differently, some having several electrode options. Finger contact, chest contact (bare skin just below the nipple), and regular chest electrodes can be used to create an ECG tracing.
Patient coaching and patient-centered care
Cardiac testing can be a stressful experience, so the medical assistant should coach the patient on what to expect before, during, and after the test, and explain any preparation or follow-up required. Address any questions from the patient or family members, and direct anything outside the medical assistant’s scope of practice to the provider. After the procedure, let the patient know who will contact them about the results and, if possible, give a timeline for when to expect that notification.
Legal and ethical issues
When a medical assistant is performing an ECG, it is important that the electrodes and lead wires are placed on the patient correctly. If the arm lead wires are reversed, the P, QRS, and T waves are negative deflections in lead I. If the left arm and left leg lead wires are reversed, Lead III is inverted, and the P wave is larger in lead I compared to lead II. Normally, the P wave is larger in lead II. Taking an ECG when the lead wires are reversed can lead to more cardiac testing and additional provider visits. The medical assistant has a professional responsibility to perform ECGs accurately so that the patient receives the best possible care.
Professional behaviors
Patients often ask the medical assistant whether their ECG looks normal, but reading the ECG is the provider’s role, not the medical assistant’s. Explain that the provider will review the results and share them with the patient, and avoid false reassurance such as “I am sure the ECG will be normal” - comments like this create a false impression and fall outside the medical assistant’s scope of practice.