History | Past medical history | Family history | Physical examination | Electrocardiogram |
Syncope during exertion (including swimming)* | Congenital heart disease (corrected or uncorrected)* | Early cardiac death or sudden death in close relatives younger than 50 years of age*¶ | Pathologic murmur (eg, systolic ejection murmur with a click [aortic stenosis] or an outflow murmur that decreases with squatting or increases with Valsalva [HCM])* | Abnormal QT intervals*Δ |
Chest pain, or palpitations prior to or during the event* | Acquired heart disease with residual abnormal function*◊ | Familial arrhythmias*¶ | Signs of heart failure (eg, gallop, rales, hepatomegaly)* | Delta wave (ventricular pre-excitation or Wolff-Parkinson-White syndrome)* |
Triggered by fright, anger, or auditory stimulus | | Familial cardiomyopathy*¶ | Four limb blood pressure with systolic gradient (arm > leg) in patients with possible coarctation of aorta*§ | Excessive bradycardia or AV block* |
Brief posturing or "seizure-like" event | | | Tachycardia (>95th percentile for age) | Left axis deviation, prominent Q waves (leads II, III, and aVF), atrial enlargement with left ventricular hypertrophy, and/or deep inverted T waves (V2 through V4) indicating HCM* |
No identifiable prodrome (eg, no lightheadedness, visual changes, or nausea) | | | Bradycardia (<5th percentile for age) | Brugada syndrome (eg, pseudo-RBBB and ST elevation in V1 to V3 leads)* |
| | | Irregular rhythm | Epsilon wave (arrhythmogenic right ventricular cardiomyopathy)* |
| | | | Signs of myocardial ischemia (eg, ST-T wave changes, Q waves)*¥ |
| | | | Findings of atrial enlargement and ventricular hypertrophy with ST segment and T wave abnormalities* |