2. Heart Failure Flashcards
(58 cards)
Describe a single cardiac cycle in left ventricle
-Mitral valve opens
-Ventricular filling
-Mitral valve closes
-Contraction
-Atrial valve opens
-Ventricular emptying
-Atrial valve closes
-Relaxation
-Mitral valve opens
What is heart failure?
-A chronic, progressive syndrome in which the heart is unable to pump sufficient blood
-Stroke volume is reduced
Give types of heart failure (based on chamber function)?
-Acute or chronic
-Left sided failure
-Right sided failure
-Biventricular failure
Describe left sided heart failure
-Occurs when the left ventricle fails to pump blood effectively into systemic circulation
-Leads to pulmonary congestion and reduced organ perfusion
Describe right sided heart failure
-Occurs when the right ventricle fails to pump blood effectively into pulmonary circulation
-Leads to systemic venous congestion
Describe biventricular heart failure
-Occurs when both the left and right ventricles fail to pump blood effectively
-Leads to combined pulmonary and systemic congestion
Give the classifications of heart failure
-Class 1: No symptoms during normal physical activity
-Class 2: Comfortable at rest, normal physical activity triggers symptoms
-Class 3: Comfortable at rest, minor physical activity triggers symptoms
-Class 4: Unable to carry out any physical activity without discomfort, may have symptoms even when resting
Give the types of heart failure (based on ejection fraction)?
-Heart failure with reduced ejection fraction: EF is less than 40%, based on systolic dysfunction
-Heart failure with preserved ejection fraction: EF is greater than 50%, based on diastolic dysfunction
-Heart failure with mildly reduced EF: EF 41-49%, shares characteristics of both HFrEF and HFpEF
Give some pulmonary clinical features of left sided heart failure
-Dyspnea on exertion
-Orthopnea (shortness of breath when lying flat)
-Paroxysmal nocturnal dyspnea
-Pulmonary edema
Give some systemic clinical features of left sided heart failure
-Fatigue and exercise intolerance
-Cold extremities and pallor (vasoconstriction)
-Low urine output
Give pulmonary clinical features of right sided heart failure
Mild dyspnea (but less prominent than in left sided HF)
Give systemic clinical features of right sided heart failure
-Peripheral edema
-Jugular venous distension
-Hepatomelogy (enlarged liver) and ascites (buildup of fluid)
-Anorexia and nausea
Give clinical features of biventricular heart failure
-Dyspnea, orthopnea, pulmonary congestion
-Peripheral oedema, JVD, hepatomegaly, ascites
-Profound fatigue, hypotension, low cardiac output
What are the causes of left side heart failure
-Ischemic heart diseases (eg myocardial infarction, coronary artery disease) impairing contractility
-Hypertension causing pressure overload
-LV hypertrophy and scar tissue reducing compliance during diastole
-Dilated cardiomyopathy (weakened LV muscle)
-Aortic stenosis or mitral regurgitation (valve disease) obstructing LV filling
Describe systolic left sided heart failure
-AKA heart failure with reduced ejection fraction
-Impaired contractility leading to increases in ESV and EDV
-Reducing cardiac output
Describe diastolic left sided heart failure
-AKA heart failure with preserved ejection fraction
-LV loses its ability to relax and fill properly during diastole, reducing EDV
-Resulting in impaired filling and increased less atrial pressure
Describe the compensatory mechanisms that occur in those with heart failure
-Activation of sympathetic nervous system: increasing vasoconstriction (via α1-adrenergic receptors) and renin release (via β1-adrenergic receptors)
Describe the Frank-Starling mechanism in a healthy heart
-The more cardiac muscle fibres are stretched during diastole (due to increased venous return), the greater the force of contraction during systole (increasing stroke volume)
Describe the Frank-Starling mechanism in a heart with heart failure
-Increased preload with increased blood volume and venous return due to compensatory mechanisms
-The heart responds to increased preload with enhanced contractility (maintaining stroke volume), however this is unsustainable (due to increased workload on the heart)
Give the drug targets for heart failure
-β antagonists
-ACE inhibitors
-Vasodilators
-Spironolactone diuretics
-Venodilators
What do treatments for heart failure focus on?
Target compensatory mechanisms, ie treating symptoms and reducing worsening
Give the compensatory mechanisms that worsen symptoms of heart failure, and how?
-Activation of the Sympathetic Nervous System, increasing afterload and myocardial oxygen demand
-Activation of the Renin-Angiotensin-Aldosterone System, increasing afterload and fluid overload/oedema
-Ventricular hypertrophy, reducing diastolic function and impairing contractility
How may positive inotropes worsen heart failure?
-Increase myocardial oxygen demand
-Increase afterload
-Risk of arrhythmias
-HEART MAY NOT TAKE IT
What is the approach to treating heart failure with preserved ejection fraction?
Focusing on managing comorbidities, such as hypertension, atrial fibrillation, ischaemic heart disease and diabetes