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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Arginine, Cardiac Pacing, Artificial, Dogs, Endothelium, Vascular, Heart Failure, Hemodynamics, Nitric Oxide, Nitroarginine, Vasoconstriction.
user
Is systemic vasoconstriction induced by inhibition of nitric oxide synthesis attenuated in conscious dogs with heart failure? Context: The aim was to test the hypothesis that endothelium dependent vasomotor control is impaired in heart failure. The haemodynamic effects of NG-nitro-L-arginine (NNA), an inhibitor of nitric oxide synthesis, were studied in five dogs with and without pacing induced heart failure. In healthy dogs, NNA increased total peripheral resistance and arterial pressure, decreasing cardiac output and heart rate. These effects were partially reversed by L-arginine. In dogs with heart failure, NNA did not change any haemodynamic variable. However, L-arginine decreased total peripheral resistance.
assistant
These findings support a physiological role for endothelium derived nitric oxide in control of vascular resistance and are in agreement with the hypothesis that endothelium dependent vasomotion may be impaired in heart failure. Final Decision: yes