Heart Failure

Question 1

Definition of heart failure

Answer 1

condition where

• heart is unable to meet the body’s demands
• although venous filling pressure is normal/raised

Question 2

Hypertrophy vs dilation

Answer 2

• Hypertrophy - increased weight/ventricular thickness
• Dilation - enlarged chamber size

Pressure load - ventricular hypertrophy
Volume load - ventricular hypertrophy & dilation

Question 3

Acute vs chronic heart failure

Answer 3

Acute Cardiac Failure

• sudden onset
• no compensatory mechanisms
• circulatory collapse, cardiogenic shock

Chronic Cardiac Failure

• gradual severity of disease
• compensatory mechanisms exceeded: increased HR, contractility, diastolic filling
• stimulated by sympathetic, RAAS

Question 4

Pathogenesis of heart failure

Answer 4

• increased cardiac work (initially increase force of contraction)
• increased wall stress (pressure/vol overload)
• hypertrophy, dilation
• exceeds compensation
• heart failure

Question 5

Effects of heart failure (2)

Answer 5

1. Forward failure - diminished CO - decreased arterial blood flow
2. Backward failure - venous congestion - incomplete pumping out of venous return - increased venous pressure

Question 6

Causes of LHF (4)

Answer 6

1. Volume overload - high o/p, valvular disease
2. Pressure overload - HTN
3. Loss of muscle/contractility - MI, infections, poisons
4. Restricted filling - pericardial effusion, restrictive pericarditis

Question 7

Effects of LHF (2)

Answer 7

1. Forward failure
   - decreased CO - hypotension
   - poor tissue perfusion & oxygenation
2. Backward failure
   - LA dilation
   - pulmonary HTN
   - pulmonary edema - impaired gas exchange

Question 8

Causes of RHF (3)

Answer 8

1. Left heart failure
2. Valvular disease
3. Cor pulmonale due to pulmonary HTN

Question 9

Effects of RHF

Answer 9

Systemic & portal venous congestion

• congestive hepatosplenomegaly
• effusions in body cavities eg ascites
• peripheral subcutaneous edema

Question 10

Edema

Answer 10

• forward failure - decreased CO - decreased BP & increased sympathetic - decreased RBF - increased RAAS - increased Na & H2O retention - increased plasma vol & cap hydrostatic pressure - increased transudation
• backward failure - increased CVP - increased cap hydrostatic pressure - increased transudation