RENAL FUNCTION DURING CARDIAC PACEMAKING

A hemodynamic and renal study was carried out on eight pacemaker-treated patients with complete heart block. At the time of study the patients were normotensive and well compensated. Cardiac output, brachial arterial pressure, inulin- and PAH-clearances as well as the excretion of electrolytes were determined on two or three selected heart rate levels between 45–118 for each patient during four to six 20-minute periods. A change of the ventricular rate from low to high level gave a significant decrease of stroke volume and pulse pressure, but cardiac output, GFR and RPF were unchanged. The most interesting result was the finding of a significantly increased sodium excretion and sodium/potassium quotient on high heart rates. Possible explanations of the mechanisms responsible for this action are discussed.