Contribution of the ventricles and the atrial appendages to the elevation of plasma atrial natriuretic factor (ANF) during pacing-induced heart failure in conscious dogs

The goal of our study was to determine whether the elevation in plasma ANF was produced by the atrial appendages or ventricular tissue during pacing-induced heart failure in chronically instrumented conscious dogs (sham) or dogs with bilateral atrial appendectomy. Acute volume expansion caused a significant elevation of plasma ANF from 80±8 to 149±26 pg/ml (p 0.05) in atrial appendectomized dogs. In response to volume expansion, there were further increases in LVEDP and LAP in both groups of dogs, but plasma ANF was not elevated (288±39 pg/ml) in sham dogs and only slightly increased (132±7 pg/ml) in atrial appendectomized dogs. Our results suggest that, during pacing-induced heart failure, the atrial appendages are the major source of elevated plasma ANF, and the remaining atrial and ventricular tissue, even when maximally stretched, can only modestly increase plasma ANF.