[Hemodynamic effects of the cold pressor test in patients with heart failure treated with beta blockers for a long time]

In congestive heart failure (CHF) the beta-adrenoceptor density and functional responsiveness is markedly reduced presumably due to endogenous down-regulation. In the last few years evidence has accumulated that betablockers therapy can improve clinical condition in selected patients with CHF. To evaluate sympathetic response in CHF we measured hemodynamic effects of cold pressor test. This study was composed by 20 patients, 10 with CHF of different origin and 10 healthy volunteers. They were divided into 4 groups in relation to therapy. We evaluated the modification of the following hemodynamic parameters during cold pressor test: heart rate, mean arterial pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, right atrial pressure, cardiac index, systemic vascular resistance, pulmonary vascular resistance. In normal subjects we observed hemodynamic modification of heart rate, mean arterial pressure and systemic vascular resistance according to many other Authors. In atenolol-treated subjects the sympathetic response is strongly attenuated. Patients with CHF not treated with betablockers showed an increase in heart rate and in systemic vascular resistance and a reduction of cardiac index. Chronic treatment with atenolol did not modify heart rate response to cold pressor test. The mean arterial pressure increased while the systemic vascular resistance did not show any significant modification. We observed a trend to increase of the cardiac index; this could explain the beneficial effect of betablockers therapy in selected patients.