Heart failure Flashcards
What is the definition of heart failure?
Clinical syndrome that can result from structural or functional cardiac disorder that impairs the ability of the heart to fill or eject blood so that there is insufficient blood flow to meet the body’s needs
What are the 2 types of chronic heart failure?
-Heart failure with reduced ejection fraction (HFrEF) or Systolic HF
-Heart Failure with preserved ejection fraction (HFpEF) or Diastolic HF
What is Class 1 of heart failure?
No limitations. ordinary physical activity does not cause fatigue, breathlessness oor palpitation
What is class 2 of heart failure?
Slight limitation of physical activity. Such patients are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, breathlessness or angine pectoris
What is class 3 of heart failure?
Marked limitation of physical activity. Although patients are comfortable at rest, less than ordinary physical activity will lead to symptoms
What is class 4 of heart failure?
Inability to carry on any physical activity without discomfort. Symptoms of congestive cardiac failure are present even at rest. With any physical activity increased discomfort is experienced
What is diastolic HF(HFpEF)?
Ventricle unable to adequately relax
and fill at normal diastolic
pressures/volumes
to maintain stroke volume
Pressure-overload in ventricles
e.g. hypertension, aortic stenosis
What is systolic HF(HFrEF)?
Inability of heart to maintain
contractility producing reduction
in ejection fraction and stroke volume
Volume-overload in ventricles
e.g. MI, IHD
What are symptoms of heart failure?
Nocturnal dyspnoea
Dyspnoea on exertion
Orthopnoea
Rales/lung crackles
Acute pulmonary oedema
Neck vein distension
Increased venous pressure
Cardiomegaly
Cough
Ankle oedema
Renal dysfunction
What is the equation for prevelance?
Prevalence = Incidence x Duration
What are the 5 causes of heart failure?
- Impaired ventricular function (Reduced pump function)
Myocardial infarction or cardiomyopathy - Pressure overload of ventricle (increased afterload)
Systemic or pulmonary hypertension - Inflow obstruction of ventricle (Reduced filling)
Restrictive cardiomyopathy
Mitral stenosis
Diastolic HF - Valvular disease
Aortic, Mitral or Tricuspid stenosis/regurgitation - Volume overload of ventricle
Ventricular and Atrial Septal defect (VSD and ASD)
What are the 3 stages in the onset and development of heart failure?
Stage 1 : Insult or stimulus
Myocardium injury / Increase chronic pressure load etc.
Decrease Contractility (pumping capacity)
Stage 2 : Compensated dysfunction
Initial preserved function
Myocardial hypertrophy and chamber dilatation
Moderate symptoms and treatment
Stage 3 : Decompensated overt failure
Gross change in heart shape - wall thinning, spherical, dilatation
Significant morbidity and mortality
Hospitalisations
What does a drop in stroke volume through ventricular failure lead to?
A drop in stroke volume through ventricular failure leads to
compensatory mechanisms to maintain cardiac output
What is the neurohormonal model for ventricular failure?
Memorise slide from ppt
What are problems with excessive increase in neurohormonal compensation?
excessive increase in neurohormonal compensation leads to
changes in O2 demand and long term changes to the heart
What are the effects of prolonged compensatory mechanism?
- Continuous sympathetic activaation
- Increased heart rate
- Increased preload
- Increased total peripheral resistance
- Continuous neurohumoral activation
Why is continuous sympathetic activation negative?
β-adrenergic downregulation and desensitization
(less contractility/inotropic response)
Why is increased heart rate a negative compensatory mechanism in the long run?
Increased metabolic demands and myocardial cell death
Why is increased preload a negative compensatory mechanism in the long run?
Beyond limits of Starling’s law, pressure is transmitted to pulmonary vasculature leading to pulmonary oedema
Why is increased total peripheral resistance a negative compensatory mechanism in the long run?
Higher afterload leading to decreased SV/CO
Why is continuous neurohumoral activation a negative compensatory mechanism in the long run?
Chronically elevated RAAS, Ang II and aldosterone trigger inflammatory responses (cytokines - activate macrophages, fibroblasts) resulting in myocardial remodelling
In diastolic HF, what type of hypertrophy occurs and therefore what happens to the heart and its muscles?
-Concentric hypertrophy
Hearts have thick walls and small cavities
-Sarcomeres added in parallel increase myocyte cell width
In systolic HF, what type of hypertrophy occurs and therefore what happens to the heart and its muscles?
-Eccentric hypertrophy
Hearts have thin walls and large cavities
-Sarcomeres added in series increase myocyte cell length
What is the diagnostic algorithm for heart failure?
- Heart failure suspected
- Request NT-proBNP test
-Sensitive test for heart failure so won’t miss any cases
-But its non specific as its also present with AF, hypertension - If BNP is normal then look for other causes of breathlessness
- If BNP is elevated, carry out an echo to confirm/refute. This is the gold standard test and will also confirm caused such as valvular, IHD, hypertensive etc.
What are the goals in the treatment of heart failure?
-Improve prognosis – reduce mortality
-Reduce morbidity – relieve symptoms, decrease frequency and length of
stay of hospital admissions
-Prevent cardiac and other end-organ damage
-Manage comorbidities - may contribute to pathogenesis of HF
What is the rationale behind the treatment for heart failure?
-Reduce myocardial O2 demands and increase stroke volume
-Reduce cardiac dilation
-Prevent arrhythmias
-Improve myocardial contractility
What are ways to reduce myocardial O2 demands and increase stroke volume in heart failure?
Surgical, e.g. valve replacement, coronary artery stents
Pharmacological – reduce preload, afterload, e.g. ACEi/ARBs
What are ways to reduce cardiac dilation in heart failure?
reduce blood volume to reduce preload, e.g.
diuretics and prevent/reverse remodelling, e.g. ACEi/ARBs
What are the ways to prevent arrhythmias in the treatment of heart failure?
reduce sympathetic nervous system activity,
e.g. β-blockers
What are the ways to improve myocardial contractility in heart failure?
β-blockers
What are pharmacological interventions for heart failure to reduce symptoms?
Loop diuretics : Reduce symptoms
What are frontline pharmacological interventions for heart failure according to NICE guidelines?
ACEi/ARB : measure urea, creatinine, electrolytes, GFR
β-blockers : start [low], measure heart rate, blood pressure
What are second line pharmacological intervention for heart failure according to NICE guidelines?
