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Action potential duration (APD) restitution and stability of reentrant. A. APD shortening and APD alternans as pacing cycle length (PCL) decreases
(computer simulation). Diastolic interval (DI) is measured from the end of the preceding action potential to the onset of phase zero of the present action
potential. As shown in these examples, the shorter the preceding DI, the shorter the APD. B. APD restitution curves with slope above 1 (solid line) or below
1 (dashed line, obtained with 50% block of the calcium current). C. and D. Spiral wave behavior several seconds after initiating a spiral wave in
homogeneous two-dimensional tissue. All cells are identical, with either a steep (C) or shallow (D) APD restitution slope. E. and F. Optically measured
surface voltage maps in an intact Langendorff rabbit heart before (E) and after (F) partially blocking the L-type calcium current with D600 (0.5 mg/mL) to
Source: Chapter 38. Mechanisms of Cardiac Arrhythmias and Conduction Disturbances, Hurst's The Heart, 13e
flatten the APD restitution slope to above 1. In E, multiple wavefronts move in a complex ventricular fibrillation (VF) pattern. In F, VF has converted to VT,
Citation:
V,armed
Walshrotor.
RA, Harrington
RA.
Hurst's
The Heart,
2011
Available at: http://mhmedical.com/ Accessed: May 07, 2017
manifested as
a stableFuster
double
Reproduced
with
permission
from 13e;
Weiss
et al.132
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