Heart Failure Pathophysiology

What is heart failure?

Heart cannot meet the body's blood-flow needs. It may result from weak squeezing or impaired filling.

What is HFrEF? (Heart Failure with Reduced Ejection Fraction)

Squeezing failure; ejection fraction below 40%. The ventricle cannot eject blood forcefully enough.

What is HFpEF?(Heart failure with preserved ejection fraction)

Filling failure; ejection fraction above 50% in slides. The ventricle is often stiff and cannot fill normally.

What is ejection fraction?

Percent of ventricular blood ejected per beat. It measures the fraction ejected, not total cardiac output.

How can MI lead to heart failure?

Damage → weak contraction → low stroke volume and output. Less muscle function means lower stroke volume and output.

What does SNS activation do in HF?

Raises heart rate and contractility. This is a short-term attempt to maintain circulation.

What does RAAS activation do in HF?

Raises blood volume and blood pressure. Fluid retention raises volume while vasoconstriction raises resistance.

Why can chronic RAAS worsen HF?

Extra fluid and resistance strain the heart. The weakened heart cannot manage the extra volume and pressure.

What is ventricular remodeling?

Changes in ventricular size, shape, or structure. These changes can make pumping progressively less effective.

What is systolic dysfunction?

Ventricle cannot squeeze effectively. This is commonly associated with myocardial damage after MI.

What is diastolic dysfunction?

Ventricle cannot relax and fill adequately. This is commonly associated with hypertension and LVH.