heart failure Flashcards
what is heart failure
fails to maintain an adequate cardiac output to meet the demands of the body
-any structural or functional abnormality that impairs ability of ventricle to eject blood (systolic HF) or fill with blood (diastolic HF)
the impact of heart failure in the UK
In-hospital mortality - 9.4%
30 day mortality in those surviving to discharge - 6.1%
Overall 30 day mortality - 14.9% (almost 1 in 7 pts)
Mortality affected by place of care
cardiology ward – 7%
general medical ward – 11%
Other ward – 14%
what is the pathophysiology of heart failure
stroke volume (contractility, preload and afterload) x heart rate = cardiac output
what is heart rate and its affect on the heart
inc HR, inc Cardiac output
Excessively high HR results in a decrease in the amount of time allowed for the ventricles to fill in diastole which causes SV and, thus CO to fall
what is stroke volume, pre and afterload
Contractility: the intrinsic ability of the myocardium to contract
Preload: the volume of blood or stretching of cardiomyocytes at the end of diastole prior to the next contraction
Afterload: the resistance/end load against which the ventricle contracts to eject blood
what is the frank-starling law
An increase in volume of blood filling the heart stretches the heart muscle fibres causing greater contractile forces which increases the stroke volume
true to a certain point… at some stage the fibres become over-stretched and the force of contraction is reduced
inc PL>inc stretch>dec contraction>dec SV + CO
What effects afterload
The greater the aortic/pulmonary pressure, the greater the afterload on the ventricles
increases with hypertension and vasoconstriction
decreases with vasodilatation
afterload increases, cardiac output decreases
what are the types of low output heart failure
Systolic heart failure
Diastolic heart failure
what is high output heart failure
increase demands on cardiac output, causing a clinical HF
heart functioning normally but cannot keep up with unusually high demand for blood to one or more organs in the body
Causes: thyrotoxicosis, profound anaemia, pregnancy, pagets disease, acromegaly, sepsis
what is systolic heart failure
Progressive deterioration myocardial contractile function
Ischaemic injury
Volume overload
Pressure overload
what is diastolic heart failure
Inability of the heart chamber to relax, expand and fill sufficiently to accommodate an adequate blood volume
Significant left ventricular hypertrophy (LVH) e.g HCM
Infiltrative disorders
Constrictive pericarditis
Restrictive cardiomyopathy
what are the causes of heart failure
Coronary Heart Disease Hypertensive Heart Disease Valvular Heart Disease Myocardial Disease/ Cardiomyopathies Congenital Heart Disease
cardiomyopathies
Diffuse disease of the heart muscle leading to functional impairment
what causes dilated cardiomyopathy
various causes, 50% familial
ETOH, pregnancy, systemic disease (SLE), muscular dystrophies
Drug toxicity (chemotherapy – anthracyclines, herceptin)
Myocarditis – Aetiology includes viral (enteroviruses – coxsackie B), HIV
what are other types of cardiomyopathy
Hypertrophic Cardiomyopathy (hereditary) Restrictive Cardiomyopathy (rare) – Amyloid the main cause in the UK
what is the pathophysiology of heart failure
Compensatory to maintain arterial pressure and perfusion of vital organs- FSM
vasoconstriction - increased venous return to the heart, increased preload, heart muscle fibres stretch, enhanced contractility
what myocardial structural change results from heart failure
Augmented muscle mass (hypertrophy) with/without cardiac chamber dilatation
Activate neurohormonal system:
Release Noradrenaline – increases heart rate and myocardial contractility. Causes vasoconstriction
Release of ANP/BNP
Activation of RAAS
what is the renin angiotensin aldosterone system
sympathetic and aldosterone increase - na+ retention and vasoconstriction
decrease in CO and BP - increase renin and angiotensin
what does angiotensin result in
Angiotensinogen > angiotensin I >angiotensin II
Arteriolar vasoconstriction
sympathetic activity
ADH secretion, H20 absorption
Adrenal gland: Aldosterone secretion - tubular Na+, Cl- reabsorption, H20 retention, K+ excretion
Water and Sodium retention
increased circulating volume, increased renal perfusion
What is the NP system
Distended ventricular wall
proBNP > NT-proBNP (non active) > excreted renally
BNP (diuresis, vasodilation, RAAS inhibition, SNS inhibitors)
what is the CNS sympathetic outflow
inc cardiac sympathetic activity (B1, B2, a1) - myocyte hypertrophy, myocyte injury, increased arrhythmias
increased vascular sympathetic activity (a1)- vasoconstriction
increased renal sympathetic activity (B2, a1) - activate RAAS and sodium retention
all leads to disease progression
how can compensatory mechanisms worsen heart failure
Vasoconstriction: ↑resistance against which heart has to pump (i.e.↑afterload), and may therefore ↓ CO
Na and water retention: ↑fluid volume, which ↑ preload. If too much “stretch” → ↓ contractile strength and CO
Excessive tachycardia → ↓diastolic filling time → ↓ventricular filling → ↓SV and CO
what are the clinical types of heart failure
Left sided, right sided and biventricular failure
Acute and chronic heart failure
Compensated and decompensated heart failure
what is left sided heart failure
Blood backs up progressively from the left atrium to the pulmonary circulation Causes: Ischaemic heart disease Hypertension Valvular heart disease Myocardial disease
how does left ventricular failure effect the lungs
Pressure in the pulmonary veins is transmitted to the capillaries and arteries
This leads to pulmonary congestion and oedema
what results from heavy wet lungs
Breathlessness (dyspnoea) exaggeration of breathlessness that follows exertion
Orthopnoea – breathlessness lying flat that is relieved by sitting or standing
Paroxysmal nocturnal dyspnoea – an extension of orthopnoea with attacks of extreme dyspnoea bordering on suffocation usually occuring at night
how does left ventricular failure affect the kidneys
Decreased cardiac output
Reduction in renal perfusion
Activation of renin - angiotensin – aldosterone system
Retention of salt and water with expansion of interstitial fluid and blood volumes
how does left ventricular failure affect the brain
Hypoxic encephalopathy Irritability Loss of attention Restlessness Stupor and coma
what is right sided heart failure
Usually consequence of left sided HF (congestive cardiac failure (CCF))
what is cor pulmonale
Right sided HF due to significant pulmonary hypertension due to increased resistance within the pulmonary circulation
Usually as a result of respiratory disease e.g. COPD or pulmonary emboli
what are other causes of right sided heart failure
Valvular heart disease
Congenital heart disease
what are the systemic effects of right heart failures
Liver and portal system Congestive hepatomegaly, Centrilobular necrosis when severe, Cardiac cirrhosis Spleen Congestive splenomegaly Abdomen Ascites Subcutaneous tissue Peripheral oedema pretibial oedema Sacral oedema if bedridden Pleural and pericardial space effusions
what is biventricular failure
same pathological process on each side of the heart
or
consequence of left heart failure leading to vol overload of the pulmonary circulation and eventually the right ventricle causing right ventricular failure
what is the clinical presentation of heart failure
Due to excess fluid accumulation Dyspnoea Orthopnoea, paroxysmal nocturnal dyspnoea Oedema Hepatic congestion Ascites Due to reduction in cardiac output Fatigue Weakness
how is heart failure classified
Class I: No limitation of physical activity
Class II: Slight limitation of ordinary activity
Class III: Marked limitation, even during less-than-ordinary activity
Class IV: Severe limitation with symptoms at rest
what are the clinical signs of cardiac failure
Cool, pale, cyanotic extremities Tachycardia Elevated JVP Third heart sound (S3) – gallop rhythm Displaced apex (LV enlargement) Crackles or decreased breath sounds at bases on chest auscultation Peripheral oedema Ascites Hepatomegaly
what clinical tests are done for heart failure to determine underlying cause
CXR ECG Blood investigations Echocardiogram / Cardiac MRI or CT / CT-PET CTCA / Coronary angiography
how is heart failure diagnosed
detailed history and clinical exam measure NT-proBNP ECG (CXR, BT, PF, urinalysis) may have specialist assessment assess severity, establish cause and correctable causes
how can heart failure be treated
diuretics for congestive symptoms and fluid retention
preserved ejection fraction - manage cormorbidities
reduced ejection fraction - ACE I or BB
all personalised exercise based cardiac rehab programme
specialist re assessment
what are loop diuretics
FRUSEMIDE, BUMETANIDE
Inhibit Na+ re-absorption from the proximal tubule
K+ loss from distal tubule
how are loop diuretics given
Can be given iv or orally
can-
electrolyte abnormalities
hypovolaemia and diminished renal perfusion
what are Mineralocorticoid Receptor Antagonists
EPLERENONE, SPIRONOLACTONE
Acts on distal tubule
Promotes Na+ excretion and K+ re-absorption
Reduces hypertrophy and fibrosis
what are side effects of Mineralocorticoid Receptor Antagonists
Gynaecomastia (esp. Spironolactone)
Electrolyte (K+ high) and renal function abnormalities
what are ACE inhibitors
RAMIPRIL, PERINDOPRIL, ENALAPRIL, CAPTOPRIL, LISINOPRIL
Act on activated renin - angiotensin system
Given orally in small doses with slow titration
Block production of angiotensin:
Vasodilatation
BP lowering
Reduce cardiac work
what are side effects of ACE inhibitors
cough, hypotension, renal impairment
what are beta blockers
BISOPROLOL, CARVEDILOL, METOPROLOL
Block the action of adrenaline and noradrenaline on adrenergic beta receptors
Slow HR, reduce BP
Given orally in small doses with slow titration
(treat arrhythmias)
what are side effects of beta blockers
Bronchospasm
Claudication
what are SA node blockades
IVABRADINE
Blocks the If channel within the SA node
Slow HR, no effect on BP
Given orally with dose titration
what are side effects of SA node blockades
Visual aura
Bradycardia
what does digoxin do
Increases myocardial contractility
Slows conduction at the AV node (use in AF)
Excreted by kidney - Toxicity important
when is digoxin used
Acute HF especially in AF
Chronic HF in selected cases
what are ARNIs
SACUBITRIL VALSARTAN
Acts on activated renin - angiotensin system
blocks breakdown of ANP/BNP
Block production of angiotensin:
Vasodilatation, BP lowering, reduce cardiac work
Promote natriuresis
Sodium excretion, vasodilatation, reduce hypertrophy and fibrosis
what are side effects of ARNIs
hypotension, renal impairment
what are other therapies for heart failure
Cardiac Resynchronisation Therapy (CRT) Implantable Cardioverter Defibrillator (ICD) Dialysis & Ultrafiltration Ventricular Assist Device (LVAD/RVAD) Intra-aortic balloon pump Cardiac transplantation (Stem cell therapy)
what is CRT (Biventricular Pacing)
Standard pacemakers equipped with two wires (or “leads”) conduct pacing signals to specific regions of heart. Biventricular pacemakers have an third lead to conduct signals directly into the left ventricle.
what do CRT s (Biventricular Pacing) do
Combination of all three leads promote synchronised pumping of ventricles, increasing efficiency of each beat and pumping more blood on the whole.
