Maintained exercise pressor response in heart failure

Sections of 1 Cardiology and of 2 Biostatistics, Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, 17033; and 3 Lebanon Veteran Affairs Medical Center, Lebanon, Pennsylvania 17042 The impact of forearm blood flow limitation on muscle reflex (metaboreflex) activation during exercise was examined in 10 heart failure (HF) (NYHA class III and IV) and 9 control (Ctl) subjects. Rhythmic handgrip contractions (25% maximal voluntary contraction, 30 contractions/min) were performed over 5 min under conditions of ambient pressure or with +50 mmHg positive pressure about the exercising forearm. Mean arterial blood pressure (MAP) and venous effluent hemoglobin (Hb) O 2 saturation, lactate and H + concentrations ([La] and [H + ], respectively) were measured at baseline and during exercise. For ambient contractions, the increase ( ) in MAP by end exercise ( MAP; i.e., the exercise pressor response) was the same in both groups (10.1 ± 1.2 vs. 7.33 ± 1.3 mmHg, HF vs. Ctl, respectively) despite larger [La] and [H + ] for the HF group ( P