Heart Failure Flashcards
notes
Define heart failure
clinical syndrome caused by the inability of the heart to supply sufficient blood flow to meet the body’s needs
Classification of heart failure?
Reduced EF (Ejection Fraction) or Preserved EF (HFrEF, HFmrEF, HFpEF) Acute or Chronic heart failure
Describe the NYHA Functional Class
4 : breathless at rest
1 : heart muscle damaged/abnormal but no symptoms
Describe heart failure epidemiology
- Prevalence 1-2% (6-10% in >65yo)
- In 2030 50% increase due to increasing prevalence rather than increasing incidence
- Commonest cause for emergency admission >65y
- 2% total NHS health care costs
- 70% of cost = hospital admissions
- Quality of life affected most
Prevalence in over 85?
1/7
Compensatory mechanisms of failing heart?
Ventricular dilatation Increased myocardial contractility Myocardial hypertrophy Sympathetic stimulation Renin-Angiotensin-Aldosterone-System (RAAS)
What’s the Frank-Starling Law?
-increased filling of the ventricle
-increased force of contraction
SV α LVEDV (left ventricular ejection end diastolic volume)
How does heart failure affect the Frank-Starling Law?
ventricle is over-stretched reducing ability to cross-link actin + myosin filaments.
Long term effects of compensatory mechanisms?
Continuous sympathetic activation Increased HR Increased preload Increased TPR Continuous neurohumoral activation
Describe the effect of continuous sympathetic activation
β-adrenergic downregulation + desensitization (less inotropic response)
Describe the effect of increased HR
Increased metabolic demands+myocardial cell death
Describe the effect of increased preload
Beyond limits of Starling’s law, pressure is transmitted to pulmonary vasculature –> pulmonary oedema
Describe the effect of increased TPR
Higher afterload –> decreased SV + CO
Describe the effect of continuous neurohumoral activation
- chronically elevated Ang II + aldosterone
- production of cytokines
- stimulate macrophages + fibroblasts
- myocardial remodelling
- loss of contractility
Equation of CO?
CO = SV x HR
Effect of ventricular dilation?
- maintains SV but exhausted
- pressure in stretched ventricle steadily increases
- restriction to filling + increased venous pressures
Why was β-blocker last option for HF?
negatively iontropic so reduce contractility of muscle but decreases afterload
Effect of increased sympathetic drive?
- decreased CO detected by baroreceptors
- central + peripheral chemoreflex activation induce A, NA, VP release
- adrenergic activation increases HR + contractility via vasoconstriction
- increased afterload
- increased cardiac work
- myocyte damage
Effect of β-blocker?
decrease BP, afterload, HR, contractility
Effect of renin-angiotensin cctivation?
-decreased CO
-renin-angiotensin activation:
vaoconstriction increases afterload
Na + H2O retention increases preload
-increases cardiac work
-myocyte damage via myocyte fibrosis, + eccentric ventricular hypertrophy
What are ACE inhibitors+ARBs?
angiotensin converting enzyme inhibitors
angiotensin-receptor blockers
Effect of ACE + ARBs?
decrease Na + H2O retention which by decreasing:
systemic vascular resistance (SVR), afterload venous p, preload
Effect of ACE + ARBs?
decrease Na + H2O retention by decreasing:
systemic vascular resistance (SVR), afterload venous p, preload
Clinical signs of HF?
Peripheral oedema (right HF) Pulmonary oedema (left HF) Congestive Cardiac Failure (left + secondary right ventricular failure)
Mechanical causes of pump failure?
Impaired ventricular function Pressure overload of ventricle Inflow obstruction of ventricle Valvular disease Volume overload of ventricle
eg of impaired ventricular function?
Myocardial infarction or cardiomyopathy
eg of pressure overload of ventricle?
Systemic or pulmonary hypertension
eg inflow obstruction of ventricle?
Restrictive cardiomyopathy
Diastolic heart failure
Mitral stenosis
eg of valvular disease?
Aortic, Mitral or Tricuspid stenosis/regurgitation
eg of volume overload of ventricle?
Ventricular + Atrial Septal defect (VSD + ASD)
What’s right ventricular failure?
- back pressure in RA
- pressure in SVC + IVC
- increases JVP
- causes oedema, right and left pleural effusion, ascites (swelling in abdomen)
What’s left ventricular failure?
- back pressure into LA
- pulmonary veins causes pulmonary oedema (leak of fluid into alveoli)
Symptoms of left ventricular failure?
Dyspnoea (Shortness Of Breath)
Orthopnoea (SOB lying flat)
Paroxysmal nocturnal dyspnoea (Sudden SOB at night)
Signs of left ventricular failure?
Pulmonary oedema
Associated features of HF?
Renal dysfunction – low perfusion + high venous pressure
Iron def – changes in iron handing
Gout
Cardiac cachexia – skeletal muscle wasting, neurohormonal + immunologically mediated
Causes of left ventricular dysfunction?
CHD, hypertension
Primary diagnosis of HF?
ischaemic heart disease dilated cardiomyopathy valvular heart disease HF w preserved ejection fraction hypertensive cardiomyopathy tachycardia cardiomyopathy pul hypertension cardiac amyloidosis
Causes of heart failure with preserved ejection fraction (HFpEF) EF>50% ?
Aging heart
Hypertension
Secondary hypertension:
Restrictive/Obliterative cardiomyopathy
Causes of heart failure with preserved ejection fraction (HFpEF) EF>50% ?
Aging heart
Hypertension
Secondary hypertension
Restrictive/Obliterative cardiomyopathy
What’s essential hypertension?
85%
What’s secondary hypertension?
Pre-eclampsia, glomerulonephritis, pheochromocytoma, Conn’s syndrome, Acromegaly,
Drugs –steroids, sympathomimetics
What’s restrictive/obliterative cardiomyopathy?
PRIME Primary: Idiopathic Radiation Infiltrative: Amyloidosis, Sarcoidosis Metabolic: Glycogen storage disease, Fabry’s disease Endomyocardial fibrosis
Why’s there re-classification of HFpEF?
No treatment yet proven to convincingly reduce morbidity or mortality
Often highly symptomatic, poor QOL
Heterogenous pathophysiology.
Clinical diagnosis of HF?
GPs correctly diagnose heart failure about 35% of the time + diagnosis is correct in about 70% of hospital admissions
What’s NTproBNP?
biomarker
BNP = Brain Natriuretic Peptide
released from heart muscle when it’s strained
What’s the diagnostic algorithm?
-suspect HF
-test for BNP:
normal = test for other causes of breathlessness
elevated = echo to confirm
Importance of NTproBNP when diagnosing HF?
Sensitive BUT not specific because raised in atrial fibrillation + hypertension
Prognostic importance
Diff cut-offs in acute + chronic HF
Importance of echocardiography when diagnosing HF?
-Confirm diagnosis
-Points to aetiology of:
Ischaemic CM
Valvular CM
Hypertensive CM
Tachycardiomyopathy
Infiltration
Why diagnose HF?
Prognosis
Treat underlying cause
What’s Left Bundle Branch Block (LBBB)?
RV contracts before LV
30% with severe HF
Progresses over time
What’s biventricular pacemaker
RA lead
LV lead
RVA lead - thread backwards via coronary sinus onto LV which paces both ventricles simultaneously
treats LBBB
Other options for HF?
Cardiac resynchronisation therapy
Heart transplant
Left ventricular assist devices
Palliative care
