A sodium channel enhancer, LY341311, increases myocardial contractile performance without increasing heart rate in conscious normal dogs: a comparison with dobutamine.
J Card Fail
; 8(1): 33-42, 2002 Feb.
Article
em En
| MEDLINE
| ID: mdl-11862581
ABSTRACT
BACKGROUND:
Catecholamines and many inotropic agents increase cardiac contractility but also cause excessive myocardial O2 consumption (MVO2). We determined if the novel Na+ channel enhancer LY341311, which increases myocardial contractility independent of beta receptors, can produce significant cardiac inotropic effects compared with dobutamine but at lower oxygen cost in conscious dogs. METHODS ANDRESULTS:
Mongrel dogs were chronically instrumented for measurement of arterial pressure, left ventricular (LV) pressure and internal diameter, coronary blood flow, and arterial and coronary sinus O2 content. Both LY341311 and dobutamine produced dose-dependent increases in LV dP/dt, dP/dt/40, fractional shortening, and cardiac stroke work and minute work estimated from the LV pressure-diameter loop. The major difference between LY341311 and dobutamine was an opposing effect on heart rate with LY341311 slightly reducing it but dobutamine markedly increasing it. LY341311 caused a significantly smaller increase in MVO2 than dobutamine (P <.05) and produced similar cardiac inotropic effects, yielding a higher cardiac mechanical efficiency than dobutamine. However, after pacing to match heart rate with dobutamine LY341311 increased MVO2 markedly, approaching the same level as with dobutamine.CONCLUSIONS:
The novel Na+ channel enhancer LY341311 caused significant increases in myocardial contractility and contractile performance without increasing heart rate. It had a beneficial energetic effect on the heart with significantly less O2 cost and improved cardiac mechanical efficiency.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Azetidinas
/
Cardiotônicos
/
Contração Miocárdica
Limite:
Animals
Idioma:
En
Revista:
J Card Fail
Assunto da revista:
CARDIOLOGIA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos