Vascular Tone in Heart Failure

Mechanisms that promote arterial vasoconstriction in heart failure

• Increase in neural and hormonal sympathetic nervous system activity
• Elevation of angiotensin II activity (due to increased renin activity)
• Elevation in arginine vasopressin activity
• Elevation in endothelin (a hormone released by the vascular endothelium that is a potent vasoconstrictor)

Comment: These factors support arterial blood pressure but increase afterload, which further aggravates the failing heart.

Mechanisms that attempt to promote arterial vasodilation (a decrease in systemic vascular resistance) in heart failure 

• An increase in arterial vasodilatory prostaglandins
• An increase in atrial and brain natriuretic peptide
• An increase in endothelium derived relaxation factor (locally mediated nitric oxide)

Comment: We are only just beginning to recognize the presence of vasodilator mechanisms in the setting of heart failure. Some of these endogenous protective mechanisms become blunted in heart failure thus rendering them relatively ineffective (such as natriuretic peptides). In general, the vasodilator mechanisms are overwhelmed by the vasoconstrictor mechanisms in heart failure. This promotes the relentless progression of heart failure.