Page 199 - Color Atlas Of Pathophysiology (S Silbernagl Et Al, Thieme 2000)

C. Conduction Block at High Rate of Excitation

Single AP 192 212 229 Rate of
excitation
–1
(min )
II

Data from dog (after Myerberg et al.) Abnormalities

Block of Cardiac Rhythm

D. Reentry
1 Rapid spread of excitation and long refractory period: protection against reentry Plate 7.7
Normal
Purkinje fiber
refractory
Velocity ϑ 100 mV
Pathway s Purkinje fiber

Myo-
t R
0.5 s cardium
No reentry, because: refractory period t R
length of the widest < ×
Myocardium excitation loop s velocity of spread
of excitation ϑ
Purkinje fibers
2 Basic causes of reentry
s t R dV/dt ϑ

0.5 s
Reentry pathway refractory time spread of excitation 189
because: too long too short too slow

Silbernagl/Lang, Color Atlas of Pathophysiology © 2000 Thieme
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