1. Volume 5, Issue 10, Pages 1382-1388 (October 2008)
U-waves and T-wave peak to T-wave end intervals in patients with catecholaminergic polymorphic ventricular tachycardia, effects of beta-blockers 
Matti Viitasalo, MD, Lasse Oikarinen, MD, Heikki Väänänen, DSc, Kimmo Kontula, MD, Lauri Toivonen, MD, FHRS, Heikki Swan, MD 
Heart Rhythm 
Volume 5, Issue 10, Pages (October 2008)
DOI: /j.hrthm
Copyright © 2008 Heart Rhythm Society Terms and Conditions

2. Figure 1
A schematic drawing showing the typical behavior of the T2-wave (A) and the U-wave (B) in 5 phases. In the first phases with regular T-waves, arrows show the timing of future T2-waves and U-waves, respectively. In phases 2 to 3, arrows show the evolution of T2-waves and U-waves with the T2-wave separating from the T1-wave and the U-wave appearing from the baseline. In phases 4 to 5, arrows show the fading of T2-waves and U-waves with the T2-wave merging with the T1-wave and U-wave disappearing in the baseline.
Heart Rhythm 2008 5, DOI: ( /j.hrthm )
Copyright © 2008 Heart Rhythm Society Terms and Conditions

3. Figure 2
Baseline electrocardiographic recording (leads V1 to V6, paper speed 50 mm/s) in a catecholaminergic polymorphic ventricular tachycardia patient (left panel). A hardly visible notching of the T-wave and a low-amplitude U-wave are best seen in leads V3 to V4. The 2 right panels with a continuous electrocardiographic signal (paper speed 25 mm/s) of the same patient during an 18-s period show an episode of simultaneous prominent T2-waves (thin arrows) and U-waves (thick arrows) (modified lead V5). Note that the initial complex of T2-wave, U-wave and P-wave splits with slowing of the heart rate, and the T2-wave moves from the complex of T2-wave and U-wave to T1-wave and finally merges with the T1, whereas the U-wave remains separated. The amplitude of the U-wave is higher than the amplitude of T1-waves and T2-waves in the first 9 beats. Note also an episode of 3 separate peaks during the repolarization. The heart rate is 100 beats/min in the beginning and 72 beats/min at the end of the strip.
Heart Rhythm 2008 5, DOI: ( /j.hrthm )
Copyright © 2008 Heart Rhythm Society Terms and Conditions

4. Figure 3
Maximal TPE intervals (higher 2 lines) and median TPE intervals (lower 2 lines) (mean ± SEM) at specified heart rates in CPVT patients (solid lines) and in control subjects (broken lines). Please note that the maximal TPE interval of CPVT patients is larger than that of control subjects only at heart rates faster than 120 beats/min (RR interval shorter than 500 ms). CPVT = catecholaminergic polymorphic ventricular tachycardia; TPE = T-wave peak to T-wave end interval.
Heart Rhythm 2008 5, DOI: ( /j.hrthm )
Copyright © 2008 Heart Rhythm Society Terms and Conditions

5. Figure 4
Median T-wave amplitude (higher 2 lines) and median U-wave amplitude (lower 2 lines) (mean ± SEM) at specified heart rates in catecholaminergic polymorphic ventricular tachycardia patients (solid line) and in control subjects (broken line).
Heart Rhythm 2008 5, DOI: ( /j.hrthm )
Copyright © 2008 Heart Rhythm Society Terms and Conditions

6. Figure 5
A continuous electrocardiographic signal (paper speed 25 mm/s) of a catecholaminergic polymorphic ventricular tachycardia patient during a 10-s period showing ventricular premature beats with the coupling interval of 370 ms that equals with the coupling interval of the U-wave (thick arrow) gradually separating from the P-wave after the extrasystoles. Note also the slower initial upstroke of the ventricular premature beats indicating a U-wave (thin arrows). The heart rate is 137 beats/min in the beginning and 113 beats/min at the end of the strip.
Heart Rhythm 2008 5, DOI: ( /j.hrthm )
Copyright © 2008 Heart Rhythm Society Terms and Conditions