Baseline characteristics
| No ECG group | ECG group | |
|---|---|---|
| Participants | N=150 | N=802 |
| Male (%) | 49 | 51 |
| Female (%) | 51 | 49 |
| Age (years old) | 15.5 | 15.5 |
| Ethnicity | 91% Caucasian, 4.7% African-American, 2.7% mixed | 71.2% Caucasian, 10.6% Asian, 9.5% mixed, 3.9% African-American, 3% Hispanic |
| Ongoing medical conditions (%) | 9.3 (6 asthma) | 18.5 (10 asthma) |
| Positive response to the PRIME-MD screening for possible trait anxiety (%) | 27 | 48.60 |
| Family member or close friend who has died of cardiac disease <50 years old (%) | 12.20 | 16.20 |
| Worried about having a heart condition (%) | 1.40 | 5 |
PRIME-MD, Primary Care Evaluation of Medical Disorders.