Heart Failure

Define Heart Failure

Heart failure is when the heart is unable to generate an adequate cardiac output

What is cardiac output based on?

Cardiac output is based on stroke volume x heart rate

What 3 things does stroke volume depend on?

Stroke volume depends on:

1. Preload

2. Afterload

3. Myocardial contractility

What is preload?

Preload is the volume of blood in the ventricle at the end of diastole

What is preload determined by?

Preload is determined by:

• Amount of blood entering the ventricle during diastole

• Amount of blood left in ventricle after systole

What is the Frank Starling law of the heart?

Frank-Starling law: the more stretched the ventricle wall is, the greater the force of contraction

What is afterload?

Afterload is the resistance the ventricles must overcome to pump blood out

What is contractility?

Contractility is how strong the muscle contracts

How does ventricular hypertrophy and myocardial infarction affect contractility?

• Ventricular hypertrophy increases contractility

• Myocardial infarction decreases contractility

What is systolic heart failure?

Systolic heart failure is when the ventricles are too weak to contract and pump blood in the heart

What three things does systolic heart failure lead to? DVP

Systolic heart failure leads to: DVP

• Decreased contractility (due to MI)

• Volume overload (due to valvular incompetence)

• Pressure overload (hypertension)

Which side does diastolic heart failure occur on?

Diastolic heart failure occurs on the left side of the heart

What is diastolic heart failure?

Diastolic heart failure is when the ventricles cannot relax properly, making it difficult for the heart to fill with enough blood during diastole

What condition can cause diastolic heart failure?

Decreased expansion of the ventricle: pericardial effusion can cause diastolic heart failure

What is Left Heart failure (congestive heart failure)

Left heart failure is the decreased cardiac output from the left ventricle to systemic circulation

What happens in the heart during left heart failure? What does this cause?

During left heart failure, blood accumulates in the left side, causing blood to back up into the lungs

• This causes pulmonary edema

What is Right heart failure?

Right heart failure is the inability of the right ventricle to move deoxygenated blood from systemic circulation into pulmonary circulation

What does right heart failure lead to?

Right heart failure leads to increased pressure in systemic venous circulation, resulting in peripheral edema

How can peripheral edema manifest on the body?

Peripheral edema can be seen in the lower limbs due to gravity and the external jugular veins

What is congestion of the viscera and what is it caused by?

Congestion of the viscera is when blood is backed up in the internal organs

• Caused by peripheral edema

What three things causes Right heart failure?

1. Left heart failure

2. Cor pulmonale

3. Right heart issues affecting right heart contractility

What is cor pulmonale?

Cor pulmonale is when right heart failure occurs in response to pulmonary disease

What are some examples of Cor pulmonale?

Cor pulmonale examples:

• COPD

• Cystic fibrosis

• ARDS

What are some examples of right heart issues that affect right heart contractility?

Right heart issues:

• MI

• Cardiomyopathies

• Valvular disease