Developmental electrophysiologic effects of propafenone and 5-hydroxypropafenone on the canine cardiac Purkinje fiber.
Standard microelectrode techniques were used to investigate the in vitro developmental electrophysiologic effects of propafenone and 5-hydroxypropafenone on the adult and neonatal canine Purkinje fiber. The tonic and frequency-dependent depressant effects of these compounds on Vmax and amplitude were similar in both age groups. However, the ability of these compounds to shorten repolarization parameters was more pronounced in the adult. The extent of reduction of abnormal automaticity produced by propafenone was greater in the neonate compared to the adult, and 5-hydroxypropafenone significantly reduced automaticity only in the neonate. The sensitivity of neonatal abnormal automaticity to the effects of these compounds may prove to be important if the use of these agents is to be expanded into the realm of therapy for pediatric automatic rhythms.
Case
C L
CL
South Carolina Children's Heart Center, Medical University of South Carolina, Charleston.
Ravin
R R
RR
Maheshwari
R
R
Gillette
P C
PC
Hewett
K W
KW
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D004285:Dogs; D004594:Electrophysiology; D005260:Female; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D011405:Propafenone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011690:Purkinje Fibers / Q000187:drug effects* / Q000254:growth & development
D000889:Anti-Arrhythmia Agents; D011405:Propafenone; C044307:5-hydroxypropafenone