Define heart failure
A clinical syndrome of progressive weakening of the hearts pumping function. Causes systemic, organ, and cellular changes. Cause of death is eventually a progressive loss of myocardial cells and arrhythmia.
Heart failure demographics
Total prevalence: 0.4-2.0% In people over 65: 6-10% Mean age is >70 years, and is the most common ailment of individuals over 65. Prevalence is increasing, likely due to environmental/lifestyle factors. Bad prognosis, with a 5 year survival rate of ~50%
Classifications or types of heart failure
Left Sided/Right Sided
Forward: LV cannot supply the body with sufficient blood, inadequate systemic perfusion.
Backward: congestion of the venous system, right or left atrium, or pulmonary system, because ventricle ejects less blood than it recieves.
Systolic: Due to reduced systolic ejection
Diastolic: Due to reduced diastolic filling
Equation to calculate the Ejection Fraction
What is the normal EF?
What EF ranges indicate certain disorders?
EF = Stroke Volume / End Diastolic Volume
Normal is 55-75%
EF is defined as Systolic Dysfunction, also called HF-REF: HF with Reduced EF
EF between 35-50% is Diastolic Dysfuction, also called HF-PEF: HF with Preserved EF
Symptoms of Left Heart, Backward Failure?
Pulmonary Rales - due to liquid in the alveoli
Dyspnea - difficulty breathing
Orthopnea - easier to breath when sitting up or standing than when laying
Paroxysmal Noctournal Dyspnea - because they are laying down, as they slip down into a laying position asleep and fluid accumulates in lung, and then they wake up suddenly with severe dyspnea. Used to be caused Cardiac asthma
Symptoms of Left Heart, Forward Failure
Weakness, Fatigue, because of insufficient systemic perfusion
Nocturia, due to increased return from the body when laying down at night.
Symptoms of Right Heart, Backward Failure
Distended neck veins
S3 gallop, the third heart sounds
Diagnosis of heart failure
Anamnesis and current complaints
ECG, no specific sign, but anyone with heart failure will have some kind of ECG abnormality
Echocardiography to measure Ejection Fraction
BNP - Brain netriuretic peptide
NT-proBNP - N-terminal pro BNP
ST2 - indicates myocardial stretch
hs-cTnT - high sensitivity cardiac troponin T,
-hs-cTnT is mildly elevated in Heart Failure. Highly elevated in Myocardial Infarct
Underlying causes of heart failure
Ischemic heart disease - Infarcts or just a more mild ischemic heart
Obestity --> Metabolic syndrome --> Diabetes + hypertension
Cardiomyopathy -> caused by alcoholism or genetic factors
What is an S3 Gallop?
An audible 3rd heart sounds
Is normal in young people or in athletes
Abnormal in people suspected of heart failure
Produced by the rapid halting of blood flow into the ventricles from the atria.
Increased workload, increased metabolic need
-activity, fever, infection, hyperthyroidism
- Renal failure, high sodium intake, hypervolemia
Pressure overload (although these are considered Circulatory Failure not exactly Heart Failure)
- High blood pressure
- Pulmonary embolism
- Cardiac Ischemia
- Decreased pump efficiency, due to Arrythmias
- Drug effects
- Infection or inflammation of the heart Endocarditis, Myocarditis
Determinants of Cardiac Output
Heart rate x Stroke Volume = CO
Things that effect stroke volume: Inotropy, Lusitropy, Preload, Afterload
Inotropy the force of contraction
Lusitropy the extent of relaxation
Draw out the Pressure-Volume loop of the heart
What portion of the graph is equal to the work of the heart?
The total area under the curve = the work of the heart
Does Ischemia cause systolic or diastolic dysfunctions?
It causes both, decreasing contractility and also decreasing flexibility
What are some of the Calcium and ATP disturbances seen in heart failure patients?
Ryanodine receptor leaks Ca++ from SR during diastole, Causes weakened contractions.
SERCA transporter is less effecient, less Ca++ in SR, more Ca++ in cytoplasm, both weakening contraction, and impairing relaxation
Less ATP and more ADP in cardiomyocytes. Due to low phosphocreatine levels.
In HF there is a shift from mostly fatty acid oxidation towards more glucose metabolism
Describe the hemodynamic defense reaction seen in HF.
Efforts of the vascular system to maintain CO and blood pressure during heart failure.
Salt and water retention
-increases preload, boosts CO, also causes edema and pulmonary edema
-increases afterload, boosts BP, also increases workload and decreases CO
-Increases contractility, relaxation, and heart rate, also increases workload and may prompt arrhythmias and sudden death
Describe the Inflammatory Reaction of Heart Failure
Low grade inflammation that occurs during HF, unclear exactly why
Benefits of it:
Produces protective proteins like Heat Shock proteins,
not exactly clear what the benefit is
Cardiac Cachexia (wasting/weight loss due to HF)
What are 3 major systemic responses to Heart Failure
Hemodynamic Defense Reaction
Describe the Hypertophic response of HF
Gene expression changes, causing both adaptive hypertrophy and maladaptive hypertrophy
Genes changes: TGF-beta and IGF-1 increased, FGF decrease
Adaptive: Increased Sarcomere Number and Cardiac Output
Maladaptive: Tissue Remodeling, Increased Energy Demand, Increased Apoptosis
How is HF treated?
1) Prevention is most important
2) Determine the underlying cause
3) Try to manage and remove precipitating causes
4) Treat Symptoms
-Diuretics to manage the congestion. Alleviates backward failure but exacerbates forward failure (still preferable tho)
5) Support heart and circulation
Implantable Cardioverter-defibrillator --> to treat malignant arryhthmias. Can act as a pacemaker for bradycardia, but can also deliver a defibrillator shock in the case of malignant arrythmia to terminate it and reset rate.
Drug treatments for Heart Failure
Beta agonists: Can save life in immediate danger, but chronic use actually shortens life span.
Digitoxin: "whip" increases heart strength
Vasodilators to decrease the load: ACE inhibitors
Beta-Blockers - definitely indicated for heart failure
ACE inhibitors and Beta blockers are good well established therapy to extend lifespan.
LVAD Left ventricular assist devices implanted