Adding ECG Picks up Abnormalities Not Detected by Physical Exam and Medical History

From Heartwire
Michael O'Riordan

March 2, 2010 (Boston, Massachusetts) — Adding electrocardiography (ECG) to a physical examination and medical history significantly improves the sensitivity of screening programs designed to detect abnormalities that would restrict participation in sports, a new study has shown

In a prospective study designed to test the current preparticipation screening program standard of care with a program that includes a 12-lead ECG, researchers showed that screening limited to medical history and physical examination missed a significant percentage of athletes at increased risk for adverse cardiac events. When the ECG was added to screening, there was an improved sensitivity for detecting diseases responsible for sports-related sudden death.

Speaking with heartwire , lead investigator Dr Aaron Baggish (Massachusetts General Hospital, Boston) said that the physical examination, medical history, and 12-lead ECG were "complementary," with the exam and history detecting individuals with valvular disease, while "the strength of the ECG was in its ability to detect myocardial abnormalities."

To heartwire , Baggish said that he agrees with most of the conclusions reached by Maron and that adding 12-lead ECG as part of a mandate for improved public health is "probably not possible at this point."
Instead, he sees the addition of 12-lead ECG to screening programs already in place, such as those around the US for high-school and collegiate sports, as well as other competitive athletic programs.
"If screening with medical history and a physical exam is already in place, then adding the ECG to pick up cardiomyopathies is something that could be done."

The study and editorial are published in the March 2, 2010 issue of the Annals of Internal Medicine.

Data From Collegiate Athletes

In this study, Baggish and colleagues performed a prospective analysis of preparticipation screening with medical history and a physical examination--the current recommended approach in the US--with an approach that includes medical history and physical examination along with a 12-lead ECG. Included in the analysis were 508 Harvard University collegiate athletes, all of whom received standard screening and who then underwent resting 12-lead ECG and transthoracic echocardiography (TTE).

Of the participants screened with TTE, the imaging gold standard, 76% had normal hearts, while another 22% had mildly abnormal findings that were consistent with physiologic remodeling. Abnormalities were detected in 11 patients, or in 2.2%, and of these, three had an abnormality that met current restrictions for permanent or temporary restriction of sports, including one individual with pulmonary stenosis, one with hypertrophic cardiomyopathy, and one with myocarditis.

When using medical history and physical examination alone, clinicians blinded to the TTE results identified five of the 11 abnormalities, all valvular heart disease. Screening with medical history and physical examination failed to identify the one patient with hypertrophic cardiomyopathy and the other with myocarditis.
When ECG screening was added, 10 of the 11 athletes with TTE-detected abnormalities were identified, including all patients who met criteria for restriction from sports.

The combined screening with medical history, physical exam, and ECG had a sensitivity of 90.9%, a specificity of 82.7%, a positive predictive value of 10.4%, and a negative predictive value of 99.8%. Screening with the ECG increased the false-positive rate to 17%, reported investigators.

Baggish said the high false-positive rate has the potential to exclude healthy athletes from sports but believes the high rate is caused by the abnormality criteria used in the study. "The adoption of ECG-based screening only makes sense if there are refined 'abnormality' criteria that account for the normal variations that are common in athletes," he commented.