Heart failure in children Flashcards
HF occurs when
the heart can no
longer meet the metabolic demands
of the body in case of normal venous
filling pressure.
Cardiac output (CO)
= stroke volume (SV) X heart rate (HR)
Compensatory mechanisms are:
◼ Increasing HR with neurohormonal controll
◼ Dilation of cardiac cavities
◼ Myocardial hypertrophy walls
Low cardiac output
Congestive HF
High output cardiac failure:
◼ Severe anemia,
◼ Sepsis with Gram -negative germs,
◼ Beriberi ( deficit vitamin B1) ,
◼ Thyrotoxicosis,
◼ Fistulas/arteriovenous malformations
Low output failure
Causes
Normal -> 5 l/min
Failure -> 3 l/min
1.Hypertensive
2.Ischaemic heart disease
3.Valvular heart disease
4.Myocarditis
High ouput failure
Pre-existing high output to meet body requirements -> 9 l/min
Failure -> 7 l/min , output still greater than normal
Diseases associated with increased blood volume :
1.Chronic Anaemia
2.Arteriovenous shunting or increased vascularity of tissues e.g. PAGET’S DISEASE OF BONE, HYPERTHYROIDISM following TRANSFUSION OVERLOAD
Pathophysiology
Myocytes exhaustion – necrosis
Stimulation of fibroblast proliferation
Cardiac dilatation and systolic
dysfunction
In the acute form:
◼ adrenergic systems and renin-angiotensin-
aldosteron system activation to maintain flow.
◼ Increasing of the myocardial contractility
with peripheral vasoconstriction, fluid retention to maintain BP
Classification
Right/left
Systolic/diastolic
HF with low CO and increased
pulmonary vascular resistance (PVR)
or increased CO and low PVR.
Functional - NYHA
NYHA functional classification
Class I: no limitation of activity ;
without symptoms to normal activities .
Class II: slight limitation of activity ;
rest without symptoms .
Class III : marked limitation of any activity ; rest without symptoms
Class IV: any physical activity is accompanied by discomfort and symptoms are present at rest
Ross classification
Score
Infant
I Asymptomatic
II Mild sweating, tachypnea at nutrition
III Tachypnea and marked sweating at nutrition
The prolongation of the nutrition time
Growth failure
IV Symptoms at rest
Children
I Asymptomatic
II Mild dyspnea on exertion
III Dyspnea on exertion
IV Dyspnea at rest
Etiology
Infant and small children
CHD with left -right shunt - the most common
◼ VSD, AVSD , PDA , CTA , aorto-pulmonary window,
◼ Single ventricle without pulmonary flow obstruction,
◼ PA (pulmonary atresia) with VSD and large MAPCAs (major aorto -
pulmonary collateral arteries)
◼ TAPVR (total abnormal pulmonary venous return) without obstruction.
Pulmonary flow increases with decreasing lung resistance
Etiology
Infant and small children
ALCAPA
( abnormal left coronary artery from
pulmonary artery) - with worsening coronary
perfusion , myocardial ischemia and dysfunction.
Etiology
Infant and small children
Cardiomyopathies
- idiopathic endomyocardial fibroelastosis,
- mitochondrial disease,
- storage disease ,
- carnitine deficiency ,
- hypertrophic cardiomiopathy, myocarditis.
Etiology
Infant and small children
Noncardiac causes:
kidney failure, sepsis, severe
anemia, residual lesions after cardiac surgery - ventricular
dysfunction, great shunts significant valvular regurgitation,
arrhythmias.
Etiology
elder children
LHI , RHI
Non-operated CHD
Left heart insufficiency (LHI):
◼ AV valve insufficiency - AVSD, congenitally corrected TGA,
◼ aortic insufficiency – VSD with Ao prolapse, infectious endocarditis.
Right heart insufficiency (RHI):
◼ Ebstein disease, associated or not with cardiac arrhythmias,
◼ Eisenmenger syndrome,
◼ Tricuspid or pulmonary regurgitation