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Catecholamines and high calcium increase the susceptibility of the isolated rabbit heart to ischemia‐ and reperfusion‐induced ventricular tachyarrhythmias
Author(s) -
ClementsJewery Hugh,
Tanga Christopher
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.639.15
The testing of novel antiarrhythmic drugs for prevention of ischemia‐induced ventricular fibrillation (VF) requires clinically‐relevant animal models with good bioassay characteristics. Currently, isolated rabbit hearts cannot be used for this purpose because they have no susceptibility to ischemia‐induced VF (Rees & Curtis 1993). We tested whether perfusion solution containing catecholamines (313 nM norepinephrine + 75 nM epinephrine) and 2.8 mM Ca could increase the susceptibility of the isolated rabbit heart to arrhythmias during ischemia and reperfusion. Rabbit hearts were perfused with control (1.4 mM Ca, no catecholamines; n=10) or high Ca‐catecholamine solution (n=8) and were subjected to 30 min regional ischemia. Perfusion with the high Ca‐catecholamine solution increased heart rate and shortened PR and QT intervals compared to controls (p<0.05) but did not significantly increase the incidence of ischemia‐induced VF (13% vs 0% in controls). However, the incidences of ischemic ventricular tachycardia (VT; 63% vs 0%), reperfusion VF (67% vs 0%) and reperfusion VT (86% vs 10%) were increased by the high Ca‐catecholamine solution (all p<0.05 vs controls). We conclude that perfusion with a high Ca solution containing catecholamines improves the bioassay characteristics of the isolated rabbit heart for testing antiarrhythmic drugs. Supported by a WVSOM intramural grant.