ECG Features

• Early repolarization: normal healthy individuals can have some ST-T segment elevation that is characterized by a distinct notch in the down stroke of the R wave with an elevated concave upward takeoff of the ST-segment at the J-point of the QRS complex; often seen in V2-V5
• Juvenile T waves: negative T-waves in V1-V3 that are typically not deep or symmetrical
• S waves in I, II, and III: seen in 20% of healthy adults
• Incomplete right bundle branch block: rSR’ in V1 with a narrow QRS interval (<120 ms), r wave amplitude <7 mm, and an R’ wave amplitude less than r or S wave amplitude