Cardiac Failure

Question 1

Outline the causes of cardiac failure

Answer 1

Neonate (duct dependent, obstructed systemic circulation) -> hypoplastic L-heart, aortic stenosis, severe coarctation of the aorta, interruption of aortic arch
i.e. DO NOT CLOSE THE DUCTUS ARTERIOSUS
* Coarctation of the aorta usually happens within the first week of life, if the ob lesion is v severe, arterial perfusion may be predominantly R-to-L with the flow of blood via the arterial duct
* Closure of the duct rapidly leads to severe acidosis, collapse and DEATH (unless duct patency is restored)

Infants (defect -> high pulmonary blood flow -> L-to-R shunt) -> persistent VSA, ASD, PDA
* The symptoms of heart failure will typically increase up to the age of 3 months, but then improve as the pulmonary vascular resistance rises
* If this is left untreated, children will develop Eisenmenger syndrome
* This is a process in which long-standing LEFT-to-RIGHT shunt (caused by a congenital heart defect) causes pulmonary hypertension and eventual reversal of the shunt into a cyanotic RIGHT-to-LEFT shunt
* This causes cyanosis
* If Eisenmenger syndrome develops, the only option is heart-lung transplant

o Older children (R- or L-HF) -> Eisenmenger (RHF), Rheumatic HD, cardiomyopathy

o Also: volume overload (anaemia or sepsis); pressure overload (HTN)

Question 2

Clinical features of cardiac failure

Answer 2

Symptoms
* Breathlessness (particularly on feeding or exertion)
* Sweating
* Poor feeding
* Recurrent chest infections

Signs
* Poor weight gain or faltering growth
* Tachypnoea
* Tachycardia
* Heart murmur, gallop rhythm
* Pallor
* Enlarged heart
* Hepatomegaly
* Cool peripheries

NOTE: features of right heart failure (e.g. ankle/ sacral oedema and ascites etc.) are RARE in developed countries but may be seen with long-standing rheumatic heart disease or pulmonary hypertension with tricuspid regurgitation and right atrial dilation

 

Question 3

Investigations of cardiac failure

Answer 3

Basic – O2 sats, BP, FBC, U&Es, Ca2+, BNP/ANP

o CXR

o ECG

o Echocardiography

Question 4

Management of cardiac failure

Answer 4

Aims:

Reduce preload
* using diuretics e.g. furosemide, or more rarely, venous dilators e.g. nitroglycerin

Enhance cardiac contractility
* Using IV agents e.g. dopamine
* Other options: digoxin, dobutamine, adrenaline, milirinone

Reduce afterload
* PO ACEi
* IV agents- hydralazine, nitroprusside, alprostadil

Improving oxygen delivery
* b-blockers e.g. carvedilol

Enhancing nutrition

If heart failure is thought to be due to a cardiac malformation:

If CYANOTIC – Prostaglandin infusion

This maintains a PDA in duct-dependent cyanotic heart disease and buys time before surgical recorrection can be performed

Echocardiography to identify the underlying structural defect if necessary and correcting that

Question 5

Complications of cardiac failure