Distinguishing normal from abnormal

A challenge in the interpretation of an athlete's ECG is the ability to accurately differentiate findings suggestive of a potentially lethal cardiovascular disorder from benign physiological adaptations occurring as the result of regular, intense training (ie, athlete's heart). Several reports have outlined contemporary ECG criteria intended to distinguish normal ECG findings in athletes from ECG abnormalities requiring additional evaluation.3–8 Despite the publication of these consensus guidelines, most sports medicine and cardiology training programmes lack a standard educational curriculum on ECG interpretation in athletes.

The impact of standardised criteria

Studies demonstrate that without further education the ability of many physicians to accurately interpret an athlete's ECG is relatively poor and may lead to an unacceptable rate of false-positive interpretations and unnecessary secondary evaluations.9 ,10 However, providing physicians standardised criteria with which to evaluate an ECG considerably improves accuracy.10 In a study involving physicians across different specialties, use of a simple two-page criteria tool to guide ECG interpretation significantly improved accuracy to distinguish normal from abnormal findings, even in physicians with little or no experience.10 Therefore, physician education in ECG interpretation is feasible and accompanied by meaningful improvements in accuracy when a reference standard is used to assist interpretation. Further education is needed to produce a larger physician infrastructure that is skilled and capable of accurate ECG interpretation in athletes.

Summit on ECG interpretation in athletes

On 13–14 February 2012, the American Medical Society for Sports Medicine (AMSSM) co-sponsored by the FIFA Medical Assessment and Research Center (F-MARC) held a ‘Summit on Electrocardiogram Interpretation in Athletes’ in Seattle, Washington. Partnering medical societies included the European Society of Cardiology (ESC) Sports Cardiology Subsection and the Pediatric & Congenital Electrophysiology Society (PACES), as well as other leading cardiologists on ECG interpretation in athletes from the USA, Europe and around the world. The goals of the summit meeting were to:

1. define ECG interpretation standards to help physicians distinguish normal ECG alterations in athletes from abnormal ECG findings that require additional evaluation for conditions associated with SCD;

2. outline recommendations for the initial evaluation of ECG abnormalities suggestive of a pathological cardiovascular disorder; and

3. assemble this information into a comprehensive resource and online training course targeted for physicians around the world to gain expertise and competence in ECG interpretation.

The consensus recommendations developed are presented in three papers:

• 4. Normal Electrocardiographic Findings: Recognizing Physiologic Adaptations in Athletes11

• 5. Abnormal Electrocardiographic Findings in Athletes: Recognizing Changes Suggestive of Cardiomyopathy12

• 6. Abnormal Electrocardiographic Findings in Athletes: Recognizing Changes Suggestive of Primary Electrical Disease13

Box 1 summarises a list of normal ECG findings in athletes that are considered physiological adaptations to regular exercise and do not require further evaluation. Table 1 summarises a list of abnormal ECG findings unrelated to athletic training that may suggest the presence of a pathological cardiac disorder and should trigger additional evaluation in an athlete.

Online E-learning ECG training module—FREE!

The Seattle Criteria will be used to develop a comprehensive online training module for physicians to acquire a common foundation in ECG interpretation in athletes. This state of the art E-learning resource provides additional ECG examples, figures and explanations, and is prepared in a user friendly educational format to optimise learning. This online training module is accessible at no cost to any physician world-wide at: http://learning.bmj.com/ECGathlete

Limitations of the Seattle Criteria

While the ECG increases the ability to detect underlying cardiovascular conditions that place athletes at increased risk, ECG as a diagnostic tool has limitations in both sensitivity and specificity. Even if properly interpreted, an ECG will not detect all conditions predisposing to SCD. In addition, the true prevalence of specific ECG parameters in athletes and in diseases that predispose to SCD is often unknown and requires further study. The Seattle Criteria were developed with thoughtful attention to balance sensitivity (disease detection) and specificity (false-positives), while maintaining a clear and usable checklist of findings to guide ECG interpretation for physicians, including new learners.

The criteria define ECG findings that warrant further cardiovascular evaluation for disorders that predispose to SCD. The criteria were developed with consideration of ECG interpretation in the context of an asymptomatic athlete age 14–35. An athlete is defined as an individual who engages in regular exercise or training for sport or general physical fitness, typically with a goal of improving performance. In the presence of personal cardiac symptoms or a family history that is positive for genetic cardiovascular disease or premature SCD, the criteria may require modification. Physicians also may choose to deviate from consensus standards based on their experience or practice setting.

The evaluation of ECG abnormalities is performed ideally in consultation with a specialist with knowledge and experience in athlete's heart and disorders associated with SCD in young athletes. As new scientific data become available, revision of the criteria may further improve the accuracy of ECG interpretation within the athletic population.