By Serena Agusto-Cox | News & Views

The electrocardiogram (ECG) is as important today as it was when it was invented in 1901 by Willem Einthoven. The more than 100-year-old test measures the small electric waves created by the human heart, and it has no replacement in clinical medicine. “The electrocardiogram is a window into the function of the heart,” says Franklin H. Zimmerman, MD, FACC, FAACVPR, senior attending cardiologist and director of cardiac rehabilitation at Phelps Memorial Hospital and assistant professor of cardiology at Hofstra University/Northwell. Dr. Zimmerman’s upcoming virtual, five-part webinar series, ECG Interpretation, From Fundamentals to Advanced, aims to provide cardiac rehabilitation (CR) staff with the knowledge they need to improve patient care and outcomes.

According to a 2023 study¹ of ECG interpretation among health care professionals, providers on average accurately read an ECG just 56.4% of the time. Dr. Zimmerman indicates that cardiology fellows in training had a proficiency rate of about 80% while nurse practitioners, allied health professionals, and others accurately interpreted ECGs approximately 50% of the time. “When it comes to emergencies, such as an acute heart attack or life-threatening arrhythmias, accuracy was still only 75% in physicians and 70% in nonphysicians. That means practitioners are inaccurately interpreting 25% to 30% of emergency ECGs,” he explains. “Proficiency in ECG interpretation is not where it should be.”

Catch Cardiac Complications With ECG

The interpretation of an ECG is a core competency that CR staff and all health care providers must learn and practice. CR staff need to be able to recognize the complications associated with cardiac disease, particularly acute coronary syndromes, according to Dr. Zimmerman. “The ECG is the quickest and most accurate tool for us to analyze whether the patient is having any cardiac coronary complications,” he explains.

In CR, patients are monitored for irregular heartbeats (i.e., arrhythmia) and other symptoms throughout each session; and being able to interpret an ECG is essential to safely monitoring each patient's recovery. “The heart is a muscle,” says Dr. Zimmerman. “What we’re trying to do in CR is improve the efficiency of the heart muscle. ECG monitoring while patients exercise enables staff to identify potentially life-threatening arrhythmias. Staff also are watching for signs of ischemia or coronary insufficiency in which blood flow is inadequate.”

Each CR patient needs to exercise up to their limits, which is why monitoring is important. Dr. Zimmerman explains, “The ECG gives us a clue as to whether any potential discomfort patients feel during exercise is cardiac-related. Patients who have undergone valve surgery — transcatheter aortic valve replacement (TAVR)  — can also experience heart block, in which the electrical impulse from the top of the heart is not getting to the bottom of the heart, leading a patient to faint or even have cardiac arrest.”

CR staff should also be cognizant of how medications can impact ECGs. “Many medications can affect the QT interval portion of an ECG, and staff need to be able to identify QT prolongation, which can signal a life-threatening arrhythmia known as Torsades de pointes,” says Dr. Zimmerman. In addition, some medications can provoke heart block or excessive bradycardia. CR professionals who can recognize these irregularities can quickly alert providers to potential cardiac issues or the need for medication changes.

In CR, heart patients are monitored two to three times per week for an hour while exercising. By interpreting the ECG correctly, CR staff can determine if the patient needs to stop exercising and alert providers to potential complications before a serious cardiac event occurs. “These quick actions can save patient lives,” Dr. Zimmerman says. In addition, sometimes patients are concerned about symptoms of palpitation or noncardiac chest discomfort and can be quickly reassured when the monitor or full 12-lead ECG is normal.

Accurate ECG Interpretation Requires Practice

ECG interpretation training often involves reading a textbook in medical or nursing school, listening to lectures, and hands-on clinical training. However, because ECG interpretation is a competency that requires practice, practitioners should continually engage with the skill to hone it, or it can be lost. “In most cases, ECG interpretation is not continuously taught, which is why my AACVPR webinar series is so important for CR staff,” says Dr. Zimmerman. "It's also the reason why I authored my new textbook, ECG Core Curriculum, which will be a tremendous resource for anyone looking to enhance their skills and find answers for any questions. I'm grateful that McGraw-Hill will be providing a 20% discount code and free shipping for attendees of the webinar."

He also points out that computerized electrocardiograms offer pre-programmed interpretations, but this programming should be considered as supplemental — not as a replacement for a skilled practitioner. “Throughout my career, good physicians have referred patients to me on the basis of an incorrect computer interpretation. In some cases, the interpretation is based on technical inaccuracies. For example, if the leads are misplaced, the readings are incorrect,” explains Dr. Zimmerman. “The computers are very good at interpreting normal ECGs, while frequently misdiagnosing atrial fibrillation or over-diagnosing myocardial infarctions.” The computer also is unaware if the patients are sitting up, their hands are trembling, or other variables that can affect the ECG readings.

All CR patients have some form of cardiovascular disease, and ECG interpretation is a core skill that CR staff need to master, not only identify possible complications, but also to measure functional capacity improvement throughout the rehabilitation process. Training and retraining are necessary to keep skills sharp, according to Dr. Zimmerman.

In each webinar session, Dr. Zimmerman has made it a point to include electrocardiograms that illustrate each session’s concepts, and participants will have an opportunity to use what they have learned. Real-world examples will provide CR professionals with an opportunity to apply the concepts of each session and identify myocardial infarction, acute and chronic coronary syndromes, cardiac arrhythmias, and more.

REFERENCES:

¹ Kashou AH, Noseworthy PA, Beckman TJ, et al. (2023) ECG interpretation proficiency of healthcare professionals. Curr Probl Cardiol 2023; 48:1-17: https://pubmed.ncbi.nlm.nih.gov/37394202/

Dr. Zimmerman’s ECG Interpretation, From Fundamentals to Advanced webinar series, beginning on Jan. 15, 2025, will explore the basics of ECG interpretation, potential complications to identify, and pharmacological impacts on cardiovascular health and recovery during CR. AACVPR offers a maximum of 5.0 continuing education (CEs) credits for the series and 1.0 CE credit for each of the individual webinars.