Effects of propranolol and nifedipine in patients with hypertension and cardiac pacemakers

Effect of propranolol and nifedipine on cardiohemodynamics were compared in 57 patients with hypertension and artificial cardiac pacemakers. Relation of these effects to type of circulation and pacing mode were investigated. Magnitude and direction of hemodynamic changes under influence of propranolol depended not only on type of circulation but also on pacing mode. In all types of circulation (hyper-, normo- and hypokinetic) propranolol depressed cardiac pump and contractile functions. This was associated with manifested progression of heart failure in patients with hypokinetic circulation. In the latter patients treated with propranolol cardiac output was significantly lower during ventricular compared to atrial pacing. Effect of nifedipide depended exclusively on type of circulation and did not differ from its action in patients with spontaneous cardiac rhythm. Characteristics of intracardiac and systemic hemodynamics inherent to different pacing modes did not affect cardiodynamic responses to propranol.