Figure 1.

A: Electrocardiographic (ECG) variations in inferolateral J waves. Left: Valsalva or strong inspiration maneuver producing J-wave amplification. Middle: Cycle length prolongation associated with either unchanged pattern or amplification. Right: Negative J waves in inferior leads and positive J waves in lateral leads. Note the increase of J wave after the pause (arrow). B: Hierarchical view of ECG and clinical risk factors. LQT = long QT; SCD = sudden cardiac death; SHD = structural heart disease; VPB = ventricular premature beat.