ETIOLOGY AND PATHOPHYSIOLOGY
Heart failure (HF) is an abnormal clinical condition involving impaired cardiac pumping
that results in the characteristic pathophysiologic changes of vasoconstriction and fluid
HF is characterized by ventricular dysfunction, reduced exercise tolerance, diminished
quality of life, and shortened life expectancy.
Risk factors include coronary artery disease (CAD) and advancing age. Hypertension,
diabetes, cigarette smoking, obesity, and high serum cholesterol also contribute to the
development of HF.
Heart failure is classified as systolic or diastolic failure.
o Systolic failure, the most common cause of HF, results from an inability of the
heart to pump blood.
o Diastolic failure is an impaired ability of the ventricles to relax and fill during
diastole. Decreased filling of the ventricles will result in decreased stroke volume
and cardiac output (CO).
HF can have an abrupt onset or it can be an insidious process resulting from slow,
progressive changes. Compensatory mechanisms are activated to maintain adequate CO.
To maintain balance in HF, several counter regulatory processes are activated, including
the production of hormones from the heart muscle to promote vasodilation.
Cardiac compensation occurs when compensatory mechanisms