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4th stage
Medicine
Lec-10
Dr.Jasim
1/12/2015
Heart Failure
Clinical syndrome that develops when the heart cannot maintain adequate output, or
can do so only at the expense of elevated ventricular filling pressure.
Results from any structural or functional abnormality that impairs the ability of the
ventricle to eject blood (Systolic Heart Failure) or to fill with blood (Diastolic Heart
Failure).
The prevalence of heart failure rises with age.
Almost all forms of heart disease can lead to heart failure.
Mechanisms of heart failure :
1. Reduced ventricular contractility
CAD (segmental dysfunction) ‘cardiomyopathy(global dysfunction)
2. Ventricular outflow obstruction
Hypertension, aortic stenosis (left heart failure)
Pulmonary hypertension, pulmonary stenosis (right heart failure).
3. Ventricular inflow obstruction
Mitral stenosis,tricuspid stenosis.
4. Ventricular volume overload
Ventricular septal defect.
5. Arrhythmia
Atrial fibrillation ,Tachycardia cardiomyopathy Complete heart block Bradycardia.
6. Diastolic dysfunction
Constrictive pericarditis, Restrictive cardiomyopathy, Cardiac tamponade.
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Pathophysiology :
Cardiac output is determined by preload (the volume and pressure of blood in the
ventricles at the end of diastole) afterload (the volume and pressure of blood in the
ventricles during systole) and myocardial contractility.
Fall in cardiac output. activates counterregulatory neurohumoral mechanisms , renin–
angiotensin–aldosterone system leads to vasoconstriction, sodium and water retention,
and sympathetic nervous system activation.
Activation of the sympathetic nervous system may initially sustain cardiac output through
increased myocardial contractility (inotropy)and heart rate (chronotropy).
Prolonged sympathetic stimulation also causes negative effects, including cardiac myocyte
apoptosis,hypertrophy and focal myocardial necrosis.
Sympathetic stimulation also causes peripheral vasoconstriction and arrhythmias.
The Vicious Cycle of Congestive Heart Failure
:
Types of Heart Failure :
1. Left, right and biventricular heart failure.
2. Diastolic and systolic dysfunction.
3. High-output failure.
4. Acute and chronic heart failure.
Decreased Blood
Pressure and
Decreased Renal
perfusion
Stimulates the
Release
of renin, Which
allows
conversion of
Angiotensin
to
Angiotensin
II
.
Angiotensin II
stimulates
Aldosterone
secretion which
causes retention
of
Na+ and Water,
increasing filling
pressure
LV Dysfunction
causes
Decreased
cardiac output
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Causes of Low-Output Heart Failure (chronic)
Systolic Dysfunction
- Coronary Artery Disease
- Idiopathic dilated cardiomyopathy (DCM)
- Hypertension
- Valvular Heart Disease
-
Diastolic Dysfunction
- Hypertension
- Coronary artery disease
- Hypertrophic obstructive cardiomyopathy (HCM)
- Restrictive cardiomyopathy
Acute Decompensaated Heart Failure
Causes:
- Acute MI
Rupture of chordae tendinae/acute mitral valve insufficiency
- Volume Overload
Transfusions, IV fluids
- Worsening valvular defect
- Pulm.embolism
- Myocarditis
Factors that may precipitate or aggravate heart failure in pre-existing heart
disease :
1. Myocardial ischaemia or infarction
2. Intercurrent illness, e.g. infection
3. Arrhythmia, e.g. atrial fibrillation
4. Inappropriate reduction of therapy
5. Administration of a drug with negative inotropic (β-blocker)or fluid-retaining
properties (NSAIDs, corticosteroids)
6. Pulmonary embolism
7. Conditions associated with increased metabolic demand, e.g. pregnancy,
thyrotoxicosis, anaemia
8. IV fluid overload, e.g. post-operative IV infusion
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Clinical Presentation of HeartFailure (Acute)
1. Sudden onset of dyspnoea that rapidly progresses to acute respiratory distress,
orthopnoea and cough.
2. The patient appears agitated, pale and clammy. The peripheries are cool to the touch
and the pulse is rapid.The BP is usually high, The jugular venous pressure (JVP) is
usually elevated.
3. Auscultation A ‘gallop’rhythm, with a third heart sound,is heard. A new systolic
murmur may signify acute mitral regurgitation or ventricular septal rupture.
crepitations at the lung bases, or throughout the lungs if pulmonary oedema is
severe.
Clinical Presentation of Heart Failure(Chronic)
Due to excess fluid accumulation:
- Dyspnea (most sensitive symptom
- Orthopnea, Paroxysmal Nocturnal Dyspnea (PND)
- Edema
- Hepatic congestion
- Ascites
Due to reduction in cardiac ouput:
- Fatigue (especially with exertion)
- Weakness
- Poor renal perfusion leads to oliguria and uraemia
Chronic heart failure is sometimes associated with marked weight loss (cardiac
cachexia).
Physical Examination in Heart Failure
1. Dyspniac
2. Cool, pale, cyanotic extremities
3. Have sinus tachycardia, diaphoresis and peripheral vasoconstriction
4. Displaced Apex
5. S3 gallop Low sensitivity, but highly specific
6. Crackles or decreased breath sounds at bases (effusions) on lung exam
7. Elevated jugular venous pressure
8. Lower extremity edema
9. Ascites
10. Hepatomegaly
11. Splenomegaly
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Measuring Jugular Venous Pressure
Complications :
1. Renal failure
2. Hypokalaemia
3. Hyperkalaemia
4. Hyponatraemia
5. Impaired liver function
6. Thromboembolism
7. Atrial and ventricular arrhythmias
8. Impaired liver function
Lab Analysis in Heart Failure:
1. CBC : Since anemia can exacerbate heart failure
2. Serum electrolytes and creatinine : before starting high dose diuretics
3. Fasting Blood glucose : to evaluate for possible diabetes mellitus
4. Thyroid function tests : Since thyrotoxicosis can result in A. Fib, and hypothyroidism
can results in HF.
5. Iron studies : to screen for hereditary hemochromatosis as cause of heart failure.
6. ANA : to evaluate for possible lupus
7. Viral studies : If viral mycocarditis suspected
8. BNP brain natriuretic pepetide
Chest X-ray in Heart Failure
Cardiomegaly
Cephalization of the pulmonary vessels
Kerley B-lines
Pleural effusions
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Cardiomegaly Pulmonary vessel congestion
Pulmonary Edema due to Heart Failure
Kerley B lines
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Further Cardiac Testing in Heart Failure
1. Exercise Testing :
Should be part of initial evaluation of all patients with CHF.
2. Coronary arteriography :
Should be performed in patients presenting with heart failure who have angina or
significant ischemia.
3. Endomyocardial biopsy :
Not frequently used , Really only useful in cases such as viral-induced
cardiomyopathy
4. Electrocardiogram:
May show specific cause of heart failure:
- Ischemic heart disease
- Dilated cardiomyopathy: first degree AV block, LBBB, Left anterior fascicular
block.
5. Echocardiogram:
- Left ventricular ejection fraction
- Structural/valvular abnormalities
Management of acute HF ( imp :D )
acute medical emergency:
1. Sit the patient up to reduce pulmonary Congestion.
2. Give oxygen (high-flow, high-concentration).
3. IV frusemide 50-100 mg
4. Administer nitrates, such as IV glyceryl trinitrate until clinical improvement occurs
or systolic BP falls.
5. Continuous monitoring of cardiac rhythm, BP .
6. Intravenous opiates must be used sparingly in distressed patients.
7. If these measures prove ineffective, inotropic agents may be required to augment
cardiac output , particularly in hypotensive patients ( Dopamine).
Management of chronic heart failure
1.
General measures
2.
Drug therapy
3.
Device therapy
4.
Cardiac transplant
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General measures :
1. Education
2. Diet
- Good general nutrition and weight reduction for the obese
- Avoidance of high-salt foods and added salt.
3. Alcohol
4. Smoking
5. Exercise
- Regular moderate aerobic exercise within limits of symptoms
6. Vaccination
- Consider influenza and pneumococcal vaccination
7. Treatment of the underlying cause of heart failure (CAD)
Drug therapy
1. Loop diuretics
2. ACE inhibitor (or ARB if not tolerated)
3. Beta blockers
4. Digoxin
5. Hydralazine, Nitrate
6. Potassium sparing diuretcs
7. Ivabradine
Diuretics
1. Loop diuretics
- Furosemide, buteminide
- diuretics produce an increase in urinary sodium and water excretion, leading to
reduction in blood and plasma volume
2. Potassium-sparing diuretics
- Spironolactone, eplerenone
- Help enhance diuresis
- Maintain potassium
- Shown to improve survival in CHF
ACE Inhibitor
Improve survival in patients with all severities of heart failure.
Begin therapy low and titrate up as possible:
- Enalapril – 2.5 mg po BID
- Captopril – 6.25 mg po TID
- Lisinopril – 5 mg po QDaily
If cannot tolerate, may try ARB
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Beta Blocker therapy
Certain Beta blockers (carvedilol, metoprolol, bisoprolol) can increase ejection
fraction, improve symptoms , reduce the frequency of hospitalisation and reduce
mortality.
Contraindicated:
1. Heart rate <60 bpm
2. Symptomatic bradycardia
3. Signs of peripheral hypoperfusion
4. COPD, asthma
5. PR interval > 0.24 sec, 2
nd
or 3
rd
degree block
Hydralazine plus Nitrates
Dosing:
- Hydralazine : Started at 25 mg po TID, titrated up to 100 mg po TID
- Isosorbide dinitrate : Started at 40 mg po TID/QID
Decreased mortality, lower rates of hospitalization, and improvement in quality of
life.
Ivabradine
It reduces hospital admission and mortality rates in patients with heart failure due to
moderate or severe left ventricular systolic impairment.
Other medication in Heart Failure :
Digoxin can be used to provide rate control in :
- patients with heart failure and atrial fibrillation.
- patients with severe heart failure, digoxin reduces the likelihood of
hospitalisation for heart failure
Statin therapy is recommended in CHF for the secondary prevention of
cardiovascular disease.
Some studies have shown a possible benefit specifically in HF with statin therapy.
Meds to AVOID in heart failure :
1. NSAIDS
- Can cause worsening of preexisting HF
2. Thiazolidinediones
- Include rosiglitazone (Avandia), and pioglitazone (Actos)
- Cause fluid retention that can exacerbate HF
3. Metformin
- People with HF who take it are at increased risk of potentially lethic lactic
acidosis.
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Implantable Cardioverter-Defibrillators for HF( ICD) –CRT
Sustained ventricular tachycardia is associated with
sudden cardiac death in HF.
About one-third of mortality in HF is due to sudden
cardiac death.
Patients with ischemic or nonischemic
cardiomyopathy, NYHA class II to III HF, and
LVEF ≤ 35% have a significant survival benefit from
an implantable cardioverter-defibrillator (ICD) for
the primary prevention of SCD.
Cardiac-Resynchronization-Therapy
Management of Refractory Heart Failure
1. Inotropic drugs:
- Dobutamine, dopamine, milrinone, nitroprusside, nitroglycerin.
2. Mechanical circulatory support:
- Intraaortic balloon pump
- Left ventricular assist device (LVAD).
3. Cardiac Transplantation