Table 1.

Demographic characteristics and history of final patient sample

Number of patients (male)	480 (287)
Age (years; mean ± SD)	34.3 ± 11.6
History	n (%)
Hypertension	45 (9.4%)
Asthma or COPD	10 (2.1%)
Structural heart disease	7 (1.5%)
Atrial fibrillation	2 (0.4%)
Actual pregnancy	6 (1.3%)
Medication
Beta-blockers	22 (4.6%)
Other antiarrhythmic agent	0 (0%)

SD Standard deviation