Heart failure Flashcards
What side of the heart does blood from muscles and organs enter?
Right side
What type of blood enters the left side of the heart?
Oxygen rich blood
What in health is the cardiac output?
5L/min
What is the stroke volume in health?
70ml
What does stroke volume mean?
Ejection at contraction
What does heart failure result from?
-Structural and or functional cardiac disorders
-The ability of the heart to function as a pump is impaired - inadequate delivery of blood to heart
What does inadequate delivery of blood to the heart result in?
Less oxygen and nutrients to the tissues
What is the mortality rate of heart failure after 5 years?
50%
What are the main causes of death in heart failure?
-Recurrent pump failure
-Sudden cardiac death
-Recurrent MI
What percent of people with heart failure also have AF?
10%
What does having HF and AF increase the risk of?
Thrombo-embolic conditions
What are the two causes of Heart Failure?
1) Pump Failure
2) Overloading
How does pump failure cause heart failure?
1) Damages heart muscle, and reduces myocardial contractility leading to systolic failure, the heart now can’t contract!
2) Ischaemic heart disease
3) Occurs acutely after MI or progressively (chronically) from diffuse fibrosis of myocardial tissue
The pressure that the chamber of the heart has to generate in order to eject blood out of the chamber, i.e. total peripheral resistance. Is the definition of what?
Afterload
Volume of blood present in a ventricle of the heart, after passive filling and atrial contraction. i.e. left ventricular end diastolic volume (amount of stretch of left ventricle). Is the definition of what?
Pre-load
What is the volume of blood coming into the heart?
Preload
What is the effect the heart must have to push blood into circulation?
Afterload
What causes pump failure?
-Ischaemic heart disease
-Myocardial infarction
-Cardiomyopathy
-Arrhythmia
-Viruses and infection
-Inflammation
-Excessive alcohol consumption
-Diffuse fibrosis (excessive fibrotic tissue, heart is still can’t pump)
How does overloading cause heart failure?
Overwork and overstretch of the cardiac muscle which can cause structural and biochemical abnormalities within cells. This can lead to decreased force, velocity of contraction an delayed relaxation.
-Excessive afterload - pressure overload
-Excessive preload - volumes overload
Is overloading reversible?
NO
Pt D has an excessive afterload and excessive pre load, what is the cause of this type of heart failure?
Overloading
What causes a patient to overload?
-Excessive afterload
-Excessive preload
When a patient has hypertension, there systemic vascular resistance is high, and there is a raised afterload on the left ventricle and causes the heart to fail, what causes this?
Excessive afterload
A patient with chronic lung disease, who’s pulmonary vascular resistance high. Therefore has pulmonary hypertension what ventricular failure would this cause?
Right ventricular failure due to excessive afterload
A patient with valve dysfunction, stenosis or incompetence, the pressure within the heart increases, why?
Excessive afterload
What is an uncommon cause of heart failure?
Excessive preload
Hypervolaemia can cause?
Excessive preload
What is the name when someone has an increased volume of blood
Hypervolaemia
What can cause Hypervolaemia?
-Excessive IV infusions
-Polycythaemia
-NSAIDS and steroids
What is it when someone over produces red blood cells?
Polycythaemia
How do steroids cause hypervolaemia?
Increase Na and H2O retention and this increases blood volume
What other factors can cause overloading?
-Excessive demand on the heart
-Anaemia - O2 carrying capacity is reduced
-Hyperthyroidism
-Thyrotoxicosis - metabolic rate increased
-Valve dysfunction
-Bradycardia or tachycardia
-Widespread vasodilation-Septic shock/cardiac output increased to raise BP
What can increase myocardial workload?
-Arrhythmia
-Anaemia
-Hyperthyroidism
-Pregnancy
-Obesity
-Infective endocarditis
-Pulmonary infection
-Change in therapy including poor compliance
Heart failure which occurs after a MI is known as?
Compensated heart failure (Acute Heart Failure)
How can an MI cause compensated HF?
Contractility of the heart immediately drops because of the damage to the heart muscle.
-Cardiac output falls
-CVS initiates compensation in order to maintain cardiac output and peripheral perfusion
If cardiac output dramatically drops due to a MI, and it is found that the patient has no cardiac reserve, CVS is unable to compensate and is overwhelmed, what type of heart failure is this?
Decompensated HF
If a patients heart failure is progressive rather than a sudden fall, what is this?
Chronic heart failure
A patient can remain in compensated HF indefinitely, what can drive them into decompensation?
Severe stress, infection, fluid overload, exertion or anaemia!
The greater the volume of blood entering the heart during diastole, the greater the volume of blood ejected during systolic contraction, this is known as what law of the heart?
Starling’s Law of the Heart
What achieve Starlings Law of the Heart?
Achieved by an increase in the stretching of muscle fibres and an increase of force of contraction.
How does the heart adapt to compensation?
Cardiac enlargement
Arterial constriction
Increased sympathetic drive
Salt and water retention
How does cardiac enlargement help to adapt the heart to heart failure?
Progressive alteration of ventricular size, shape and function.
-The cardiac muscle is stretched from increased residual volume after contraction
-The muscle is ineffectual
-Responsible for significant impairment of the heart as a pump