Etafenone

Mongrel dogs (both sexes, 20-39 kg, starved for 24 h, anaesthetized)^[3]

0.1 mg/kg/min; 0.5 mg/kg/min; 0.5 mg/kg/min (following propranolol pretreatment)

i.v.; infusion over 10 min

Produced non-significant slight increases in heart rate, coronary conductance, femoral conductance, expiratory CO₂, and non-significant slight decreases in arterial and left ventricular blood pressure; no change in dp/dt at 0.1 mg/kg/min.
Produced significant increases in heart rate, coronary conductance (significant only at 6-12 min), femoral conductance, left ventricular dp/dt, expiratory CO₂, and myocardial oxygen consumption (significant only at 2-4 min); caused a significant fall in systemic blood pressure throughout the infusion; peak left ventricular blood pressure was unchanged; all parameters returned to preinfusion values 5-10 min post-infusion except heart rate and femoral conductance at 0.5 mg/kg/min.
Completely abolished increases in heart rate and dp/dt seen without β-blockade, with dp/dt showing a significant reduction from 10 min onwards; significant increases in coronary conductance, femoral conductance, and expiratory CO₂ persisted but were significantly reduced compared to pre-β-blockade levels; systemic and left ventricular blood pressure decreased significantly throughout the infusion and remained lowered during the observation period at 0.5 mg/kg/min after propranolol pretreatment.