Cardiology Flashcards
Machinery murmur
left subclavian thrill
large volume, bounding, collapsing pulse
wide pulse pressure
heaving apex beat
A premature infant is admitted to hospital following signs of heart failure soon after birth. She has poor feeding associated with heavy sweating and tiring out. This has resulted in her not gaining weight as expected. Her parents also report irritability and periods of apnoea.
On examination, bounding peripheral pulses and a continuous machinery murmur are identified. An echocardiogram shows left ventricular enlargement and a shunt between two of the great vessels.
Patent Ductus Arteriosus
What is PDA? What risk if left open?
- a form of congenital heart defect
- generally classed as ‘acyanotic’. However, uncorrected can eventually result in late cyanosis in the lower extremities, termed differential cyanosis
- connection between the pulmonary trunk and descending aorta
- usually, the ductus arteriosus closes with the first breaths due to increased pulmonary flow which enhances prostaglandins clearance
- Persistent if failure to close 1+ month after estimated due date
- Flow from aorta to pulmonary artery due to decreased vascular resistance after birth
- more common in premature babies, born at high altitude or maternal rubella infection in the first trimester
Bacterial endocarditis, growth failure and pulmonary vascular disease (pulmonary hypertension)
PDA Ix
CXR and ECG → normal if small, if large, findings same as VSD (cardiomegaly and enlarged pulmonary arteries)
Echo → to distinguish PDA and VSD
The echocardiogram ruled out other defects - however, if another defect was present, it may be preferable to use prostaglandin E1 to keep the duct open until after surgical repair.
PDA Mx
-
indomethacin or ibuprofen
- given to the neonate if ECHO shows PDA 1 week after delivery
- inhibits prostaglandin synthesis
- closes the connection in the majority of cases
- if associated with another congenital heart defect amenable to surgery then prostaglandin E1 is useful to keep the duct open until after surgical repair Prostaglandins would have the opposite effect i.e. maintaining the patency of the DA. They are sometimes used where a PDA is desirable, such as if there is co-existing right-to-left shunt defect where the PDA may be the only way for oxygenated blood to mix with deoxygenated blood.
If pharmacological methods are unsuccessful, surgical ligation or percutaneous catheter device closure may be used
What are the four features of tetralogy of fallout
Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease. It typically presents at around 1-2 months, although may not be picked up until the baby is 6 months old. However, at birth transposition of the great arteries is the more common lesion as patients with TOF generally present at around 1-2 months
- VSD
- Right Ventricular Hypertrophy
- Right ventricular outflow tract obstruction, pulmonary stenosis
- Overriding aorta
What determines the severity of tetralogy of fallot
The severity of the right ventricular outflow tract obstruction determines the degree of cyanosis and clinical severity
Other features of Tetralogy of Fallot and Ix
Cyanosis and Tachypnoea AKA Tet spells → LoC
- unrepaired TOF infants may develop episodic hypercyanotic ‘tet’ spells due to near occlusion of the right ventricular outflow tract
- features of tet spells include tachypnoea and severe cyanosis that may occasionally result in loss of consciousness
- they typically occur when an infant is upset, is in pain or has a fever
causes a right-to-left shunt
ejection systolic murmur due to pulmonary stenosis (the VSD doesn’t usually cause a murmur)
a right-sided aortic arch is seen in 25% of patients
Ix:
- CXR shows a ‘boot-shaped’ heart
- ECG shows right ventricular hypertrophy
- Echo → shows cardinal features but cardiac catherization may be required to show detailed anatomy of the coronary arteries.
Mx of hypercyanotic spells in ToF
Hypercyanotic spells (attacks of paroxysmal hyperpnoea and increased cyanosis that occur spontaneously/ after feeding/ prolonged crying/ defecation)
- Place the patient in the knee-to-chest position
- Administer oxygen
- Insert IV line and administer phenylpephrine, morphine sulphate and propranolol (vasoconstriction)
- Prolonged attacks require sodium bicarbonate (for acidosis)
- Refer to cardiac centre
Tof Mx
surgery at 6m (close VSD and relieve R outflow obstruction).
If very cyanosed neonate, insert shunt to increase pulmonary blood flow between subclavian and pulmonary (Blalock-Taussig).
Give examples of acyanotic CHD
VSD (30%)
ASD
PDA
Coarctation of the aorta
Aortic valve stenosis
NB: VSDs are more common than ASDs. However, in adult patients ASDs are the more common new diagnosis as they generally presents later.
Give examples of cyanotic CHD
- tetralogy of Fallot
- transposition of the great arteries (TGA)
- tricuspid atresia
- pulmonary stenosis, pulmonary atresia
- Ebstein’s anomaly
Fallot’s is more common than TGA. However, at birth TGA is the more common lesion as patients with Fallot’s generally presenting at around 1-2 months
The presence of cyanosis in pulmonary valve stenosis depends very much on the severity and any other coexistent defects.
What are some complications of VSD?
aortic regurgitation
- aortic regurgitation is due to a poorly supported right coronary cusp resulting in cusp prolapse
infective endocarditis
Eisenmenger’s complex
- due to prolonged pulmonary hypertension from the left-to-right shunt
- results in right ventricular hypertrophy and increased right ventricular pressure. This eventually exceeds the left ventricular pressure resulting in reversal of blood flow
- this is turn results in cyanosis and clubbing
- Eisenmenger’s complex is an indication for a heart-lung transplant
right heart failure
pulmonary hypertension
- pregnancy is contraindicated in women with pulmonary hypertension as it carries a 30-50% risk of mortality
Why is prostaglandin E1 given in cyanotic congenital heart disease (PDA)
What would make the condition worse?
his is used to maintain a patent ductus arteriosus that allows for mixing of oxygenated and deoxygenated blood, and therefore prevents the formation of two closed loops and therefore global ischaemia.
IV ibuprofen would be contraindicated in this situation. This would close the ductus arteriosus and so would make the condition dramatically worse.
When peripheral and central cyanosis happens in neonatal period
Peripheral cyanosis, for example of the feet and hands, is very common in the first 24 hours of life and may occur when the child is crying or unwell from any cause
Central cyanosis can be recognised clinically when the concentration of reduced haemoglobin in the blood exceeds 5g/dl
Initial management of suspected cyanotic congenital heart disease
- supportive care
-
prostaglandin E1 e.g. alprostadil
- used to maintain a patent ductus arteriosus in ductal-dependent congenital heart defect
- this can act as a holding measure until a definite diagnosis is made and surgical correction performed
Mx of TGA (transposition of great arteries)
- maintenance of the ductus arteriosus with prostaglandins (alprostadil)
- surgical correction is the definite treatment (balloon atrial septostomy, arterial switch in first 2 weeks of life)
TGA what is it and clinical features
Transposition of the great arteries (TGA) is a form of cyanotic congenital heart disease. It is caused by the failure of the aorticopulmonary septum to spiral during septation. Children of diabetic mothers are at an increased risk of TGA.
Basic anatomical changes
- aorta leaves the right ventricle
- pulmonary trunk leaves the left ventricle
Clinical features
- cyanosis
- tachypnoea
- loud single S2
- prominent right ventricular impulse
- ‘egg-on-side’ appearance on chest x-ray
- ACIDOSIS AND HYPOGLYCAEMIA
Give 3 innocent murmurs (children)
Ejection murmurs
Venous hums
Still’s murmur
Give some characteristics of an innocent ejection murmur
- soft-blowing murmur in the pulmonary area or short buzzing murmur in the aortic area
- may vary with posture
- localised with no radiation
- no diastolic component
- no thrill
- no added sounds (e.g. clicks)
- asymptomatic child
- no other abnormality
Timing of cardiological presentations
Timing of cardiological presentations
How do we manage Congenital Cyanotic Heart Disease?
Stabilise airway and breathing
- consider intubation and hypoxia test = start 100% O2 for 10 minutes, if spO2 persistently low → CCHD, supplemental O2 to maintain 75-85% O2 sats
Circulation
- 2 IV cannula or umbilical vein/artery catheter (UVC/UAC)
- 10ml/kg crystalloid bolus (max 30ml/kg) for hypotension, adrenaline for tx resistant hypotension
Maintain duct patency
- PG E1 infusion = most infants 1st week of life duct-dependent
- side-effects = apnoea, hypoglycaemia (jitteriness, flushing), seizures, vasodilation, hypotension, fever
Check blood glucose regularly
ToF mx:
If severe worsening cyanosis:
- PGE1 infusion
- Bialock-Taussig shunt = artificial tube between subclavian and pulmonary artery
Surgery = repair underlying heart defect from 4m onwards (closing VSD, relieving RVOTO)
Complications:
- hyper cyanotic spells = knee-to-chest, oxygen, IV line + phenylephrine + morphine sulphate + propranolol, prolonged attacks need sodium bicarbonate, refer to cardiac centre
