Capillary Density of Skeletal Muscle: A Contributing Mechanism for Exercise Intolerance in Class IIâ•fiIII Chronic Heart Failure Independent of Other Peripheral Alterations

RESULTS The patients with CHF demonstrated a reduced peak oxygen consumption when compared to controls (15.0 � 2.5 vs. 19.8 � 5.0 ml�kg�min, p �0.05). Using cell-specific antibodies to directly assess vascular density, there was a reduction in capillary density in CHF measured as the number of endothelial cells/fiber (1.42 � 0.28 vs. 1.74 � 0.35, p � 0.02). In CHF, capillary density was inversely related to maximal oxygen consumption (r � 0.479, p � 0.02). The MHC IIx isoform was found to be higher in patients with CHF versus normal subjects (28.5 � 13.6 vs. 19.5 � 9.4, p �0.05).