Peripheral chemoreceptor inhibition with dopamine in heart failure patients decreased ventilation (P=0.02) and total peripheral resistance (P=0.003), and increased cardiac index (P≤0.01) at rest.
RCT (n=21)
randomized
Does peripheral chemoreceptor inhibition with dopamine or hyperoxia alter cardiovascular and ventilatory control at rest and during exercise in heart failure patients compared to controls?
Peripheral chemoreceptors contribute to cardiovascular control at rest in heart failure patients, as evidenced by improved hemodynamics during chemoreceptor inhibition with dopamine.
Peripheral chemoreceptor activity/sensitivity is enhanced in chronic heart failure (HF), and sensitivity is linked to greater mortality. This study aimed to determine the role of the peripheral chemoreceptor in cardiovascular control at rest and during exercise in HF patients and controls. Clinically stable HF patients (n = 11; ejection fraction: 39 ± 5%) and risk-matched controls (n = 10; ejection fraction: 65 ± 2%) performed randomized trials with or without dopamine infusion (2 μg·min(-1)·kg(-1)) at rest and during 40% maximal voluntary contraction handgrip (HG) exercise, and a resting trial of 2 min of inspired 100% oxygen. Both dopamine and hyperoxia were used to inhibit the peripheral chemoreceptor. At rest in HF patients, dopamine decreased ventilation (P = 0.02), decreased total peripheral resistance index (P = 0.003), and increased cardiac and stroke indexes (P ≤ 0.01), yet there was no effect of dopamine on these variables in controls (P ≥ 0.7). Hyperoxia lowered ventilation in HF (P = 0.01), but not in controls (P = 0.9), indicating suppression of the peripheral chemoreceptors in HF. However, no decrease of total peripheral resistance index was observed in HF. As expected, HG increased heart rate, ventilation, and brachial conductance of the nonexercising arm in controls and HF patients. During dopamine infusion, there were no changes in mean arterial pressure, heart rate, or ventilation responses to HG in either group (P ≥ 0.26); however, brachial conductance increased with dopamine in the control group (P = 0.004), but decreased in HF (P = 0.02). Our findings indicate that the peripheral chemoreceptor contributes to cardiovascular control at rest in HF patients and during exercise in risk-matched controls.
Edgell et al. (Fri,) conducted a rct in chronic heart failure (n=21). Dopamine infusion and hyperoxia vs. Without dopamine infusion / risk-matched controls was evaluated on Cardiovascular and ventilatory responses (ventilation, total peripheral resistance index, cardiac and stroke indexes). Peripheral chemoreceptor inhibition with dopamine in heart failure patients decreased ventilation (P=0.02) and total peripheral resistance (P=0.003), and increased cardiac index (P≤0.01) at rest.