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Figure 2 The Valt changes asymmetrically with heart rate acceleration then deceleration, showing hysteresis on either side of the heart rate symmetry line (400 ms CL pacing). A, Inducible patients showed significant increases in Valt as the pacing rate increased from 100 beats/min (600 ms CL) to 120 beats/min (500 ms CL) to 150 beats/min (400 ms CL) for all regions of repolarization. Valt was significantly greater during deceleration than acceleration at 120 beats/min (R; p = 0.015), with redistribution from RL toward RE and RM (RM > RL; p = 0.045). Valt resumed baseline at 100 beats/min. B, Noninducible patients showed different hysteresis without an acceleration-related increase in Valt, but then an increase on deceleration to 120 beats/min (p = 0.004) and to 100 beats/min (p = 0.049) with earlier redistribution of RPA (RM > RL, p = 0.048; RM > RE, p = 0.041).