Partial 4 - Heart Failure

Question 1

Preload

Answer 1

the pressure that the end diastolic volume exerts on the ventricles of the heart, and if it increases the force of contraction during systole increases.

Question 2

Afterload

Answer 2

expressed as tension which must be developed in the wall of ventricles during systole to open semilunar valves and eject blood to aorta/ pulmonary artery. This is described by Laplace law

Question 3

Systolic failure is characterized by

Answer 3

• Ventricular dilatation
• Reduced ventricular contractility (either generalized or localized)
• Diminished ejection fraction (less than 45%)
• In failing heart, the left ventricular end-diastolic volume (or pressure) may increase as the stroke volume (or CO) decreases.

Question 4

Diastolic failure is characterized by

Answer 4

• Small or normal ventricular cavity size
• Myocardial contractility is normal or hyperdynamic
• Ejection fraction is normal (above 50%) or supranormal
• Ventricle is usually hypertrophied
• Ventricle is filling slowly in early diastole (during the period of passive filling)
• End-diastolic ventricular pressure is increased

Question 5

Main causes of diastolic failure

Answer 5

Structural disorders; which can be intramyocardial (myocardial fibrosis, amyloidosis, hypertrophy, myocardial ischemia), or they can be extramyocardial such as constrictive pericarditis

Functional disorders; Where there is decreased relaxation of chambers (myocardial ischemia, advanced hypertrophy of ventricles, failing myocardium, asynchronism in heart functions).

Question 6

Forward failure symptoms

Answer 6

result from inability of the heart to pump enough blood to the periphery (from left heart) leading to muscle weakness, fatigue, dyspnea, and oliguria, or to the lungs (from the right heart) leading to complications in gas exchange.

Question 7

Backward failure symptoms

Answer 7

result from inability of the heart to accept the blood coming from periphery (right heart) leading to peripheral edema, hepatomegaly, ascites as well as increased nocturnal diuresis, and inability to accept blood coming from the lungs (left heart), leading to dyspnea, tachypnea, pulmonary edema which leads to arterial hypoxemia and hypercapnia.

Question 8

Causes of left ventricular failure

Answer 8

Volume overload
Pressure overload
Loss of muscles
Restricted filling

Question 9

Volume overload (Causes of left ventricular failure)

Answer 9

occurs in regurgitation of valves, and in cases of high output status

Question 10

Pressure overload (Causes of left ventricular failure)

Answer 10

occurs in systemic hypertension, and in case of outflow obstruction

Question 11

Loss of muscles (Causes of left ventricular failure)

Answer 11

occurs, in post MI, chronic ischemia, connective tissue diseases, infection, and poisons

Question 12

Restricted filling (Causes of left ventricular failure)

Answer 12

occurs in, pericardial diseases, restrictive cardiomyopathy, and tachyarrhythmias.

Question 13

Symptoms of Heart Failure

Answer 13

Dyspnea
Orthopnea
Paroxysmal nocturnal dyspnea
Low cardiac output symptoms
Abdominal symptoms such as anorexia, nausea, abdominal fullness
Rt hypochondrial pain.

Question 14

Physical signs of Heart Failure

Answer 14

• BP and occasional decrease in systolic BP
• Jugular vein distention
• Inspiratory rales
• Displaced and sustained apical impulses
• Third heart sound (low pitched sound heard during rapid filling of ventricle)
• Fourth heart sound (at the end of diastole)
• Pale, cold and sweaty skin.

Question 15

Forms of Heart Failure

Answer 15

• Systolic and diastolic
• High output failure (which occurs in pregnancy, anemia, thyrotoxicosis, A/V fistula, Beriberi, and Paget’s disease)
• Low output failure
• Acute failure (large MI, aortic valve dysfunction
• Chronic failure.

Question 16

Causes of right sided heart failure

Answer 16

Most common cause is left sided heart failure. Other causes include cor pulmonale, pulmonary embolism and RV infarction.

It usually presents with lower limb edema, ascites, hepatic congestion, cardiac cirrhosis, azotemia and encephalopathy

Question 17

Causes of left sided heart failure

Answer 17

Most common causes are ischemic heart disease, systemic hypertension, mitral or aortic valve disease, and cardiomyopathies.

Symptoms include dyspnea, orthopnea, cardiomegaly, tachycardia, a third heart sound, prerenal azotemia and hypoxic encephalopathy.

Question 18

Major Criteria of Heart Failure

Answer 18

PND (Paroxysmal nocturnal dyspnea)
JVD (Jugular venous distention)
Rales
Cardiomegaly
Acute Pulmonary Edema
S3 Gallop
Positive hepatic jugular reflex
Increased venous pressure > 16cm H2O

Question 19

Minor Criteria of Heart Failure

Answer 19

Hepatomegaly
Pleural effusion
LL (lower limb) edema
Night cough
Dyspnea on exertion
Decreased vital capasity by 1/3 of normal
Tachycardio 120 bpm
Weight loss 4,5 kg over 5 days managment