Heart Failure

Chua Lausanne
041303019
Group B3


Heart Failure

· state that develops when the heart cannot maintain an adequate cardiac output, or can do so only at the expense of an elevated filling pressure.
· Congestive heart failure is a multisystem derangement that occurs when heart is no longer able to eject the blood delivered to it by the venous system. - May involve left side, right side, or all of the cardiac chambers
· Inadequate cardiac output (forward failure) is almost always accompanied by increased congestion of the venous circulation (backward failure)
· Predisposing conditions include coronary artery disease, cigarette smoking, hypertension, overweight, diabetes mellitus, and valvular heart disease.
· It has a poor prognosis

Mechanisms

1) Inappropriate workloads placed on the heart
· Volume overload: mitral/aortic regurgitation, ASD, VSD, anemia, hyperthyroidism
· Pressure overload: hypertension and aortic stenosis pulmonary hypertension & pulmonary valve stenosis
2) Restricted filling of the heart
· Ventricular inflow obstruction: mitral / tricuspid stenosis, endomyocardial fibrosis, left ventricular hypertrophy, pericardial and infiltrative diseases
3) Myocyte loss
· in myocardial infarction & connective tissue diseases like SLE.
4) Decreased myocyte contractility
· in infections, like myocarditis/cardiomyopathy or in myocardial infarction

Pathophysiology

1) Hemodynamic Changes
2) Neurohumoral Changes
Ø Sympathetic system activation
Ø Renin-angiotensin system activation
Ø Vasopressin release
Ø Cytokine & endothelin release
Ø Cellular Changes

Types of Heart Failure

1) Acute and chronic heart failure
2) Left, right and biventricular heart failure
Ø Left-sided heart failure
Ø Right-sided heart failure
Ø Biventricular heart failure
3) Forward and backward heart failure
4) Systolic and diastolic dysfunction
Ø Systolic dysfunction
Ø Diastolic dysfunction
5) High output failure

Clinical Features

· Left ventricular failure
Ø dyspnoea
Ø orthopnea
Ø paroxysmal nocturnal dyspnoea
Ø enlarged heart
Ø tachycardia
Ø hird heart sound (S3)
Ø fine crepts at the lung bases
Ø murmurs
Ø atrial fibrillation (irregularly irregular pulse)

· Right ventricular
Ø dypsnoe
Ø raised JVP
Ø enlarged, tender liver
Ø pedal edema
Ø pleural effusions
Ø ascites.

· Congestive heart failure
Ø cyanotic and acidotic
Ø cardiac cachexia-TNF is elevated

Complications

· Uraemia
· Hypokalaemia
· Hyperkalaemia
· Hypernatraemia
· Impaired liver function
· Thromboembolism
· Arrhythmias

Classification of severity (NYHA)
Class I symptoms only at levels that would limit normal individuals
Class II symptoms with ordinary exertion
Class III symptoms on less than ordinary exertion
Class IV symptoms at rest

Investigations

· Complete blood count
· Blood urea and electrolytes
· Thyroid function test
· ECG
· Chest radiograph
· Echocardiography

Management

· General measures
Ø Education
Ø diet
Ø alcohol (abstinence is required)
Ø stop smoking
Ø exercise
Ø vaccination (esp influenza & pneumoccocal)
· Drug therapy
Ø Vasodilators:
a) ACE inhibitors & Angiotensin receptor blockers (ARBs)
b) Organic nitrates
c) Hydralazine
d) Sodium nitroprusside
e) Alpha receptor blockers
Ø Diuretics
a) Thiazide diuretics: hydrochlorothiazide etc
b) Loop diuretics : furosemide, bumetanide etc.
c) Aldosterone antagonists: spironolactone
Ø ß- Adrenergic receptor blockers: carvedilol, metoprolol, bisoprolol.
Ø Inotropic agents
a) Cardiac glycosides: (eg Digoxin)
b) Dopamine & Dobutamine
c) Phosphodiesterase inhibitors: inamrinone,milrinone.
· Others
Ø Revascularisation
Ø Heart transplantation

Dengue

• flavivirus
• vector:Aedes aegypti
• 4 serotypes dengue virus

clinical feature

• incubation period:2-7 days
• asymptomatic infections are common
• fever,backache,arthralgias,headache,nausea,vomitin g
• fever:continuos or 'saddli-back'
• rash:morbiliform rash,blanches under pressure

Dengue Haemorrhagic fever

• more in children
• thrombocytopenia & haemoconcentration
• pathogenesis is unclear
• heterotypic antibody causes enhanced virus entry & replication in previous dengue infection with a different serotype or from acquired maternal antibody in infants,facilitates development of a very heavy viral load
• DIC, complement activation & release of vasoactive mediators

Investigation

• full blood count
• fourfold rise in IgG titres
• PCR

treatment

• No specific treatment
• volume replacement , blood transfusion & management of shock
• No vaccine
• insecticides to kill vector