Pathophysiology of heart failure

Question 1

List 3 factors that affect cardiac contractile force.

Answer 1

Preload

Sympathetic nervous system activation

Medications

Question 2

What is the prevalence of heart failure in the adult population? What percentage does this increase to after the age of 70?

Answer 2

1-2%, increases to 10% in those over 70

Question 3

What percentage of patients die within 5 years of diagnosis of heart failure?

Answer 3

60 - 70%

Question 4

Chronic heart failure can be classified structurally based on what factor?

Answer 4

Left ventricular ejection fraction

Question 5

What is the formula for calculating ejection fraction?

Answer 5

EF = (SV/EDV) x 100

Ejection fraction = (stroke volume / end diastolic volume) x 100

Question 6

What is the normal range for left ventricular ejection fraction?

Answer 6

50 - 70%

Question 7

How is cardiac output calculated?

Answer 7

Stroke volume x heart rate

Question 8

What is Class I in the New York Heart Association classification?

Answer 8

No limitation of physical activity

Question 9

What is Class II in the New York Heart Association classification?

Answer 9

Slight limitation of physical activity

Question 10

What is Class III in the New York Heart Association classification?

Answer 10

Marked limitation of physical activity

Question 11

What is Class IV in the New York Heart Association classification?

Answer 11

Unable to carry on any physical activity without discomfort

Question 12

List the 4 main causes of heart failure.

Answer 12

Coronary heart disease (myocardial infarction)

Atrial fibrillation

Valvular heart disease

Hypertension

Question 13

List 3 compensatory mechanisms of heart failure.

Answer 13

Activation of RAAS and sympathetic nervous system

Ventricular hypertrophy