Cardiovascular Flashcards
Normal heart rates of children
<1y: 110-160 bpm
2-5y: 95-140 bpm
5-12y: 80-120 bpm
<12y: 60-100 bpm
Cardiac failure clinical presentation
Poor weight gain/faltering growth Tachypnoea Tachycardia Heart murmur, gallop rhythm Cardiomegaly Hepatomegaly Cool peripheries Breathlessness - particularly on feeding/exertion Sweating Poor feeding Recurrent chest infections
Heart failure in the 1st week of life
Usually results from coarctation of the aorta
If obstructive lesion is severe then arterial perfusion may be predominantly R-to-L via patent ductus arteriosus
Closure of this duct leads to severe acidosis, collapse and death unless ductal patency is restored
Heart failure >1w of life
Progressive heart failure is most like due to L-to-R shunt
Pulmonary vascular resistance falls in first weeks which causes progressive increase in L-to-R shunt and increase pulmonary blood flow causes pulmonary oedema and breathlessness
Symptoms may improve >3m as pulmonary vascular resistance increases
What is Eisenmenger syndrome
Irreversible increased pulmonary vascular resistance
If L-to-R shunt left untreated
Can lead to reversal of the shunt (R-L) at 10-15 years and the teenager becomes blue
Treatment: heart-lung transplant
Neonatal causes of heart failure
Obstructive duct-dependant lesions: Hypoplastic left heart syndrome Coarctation of the aorta Critical aortic valve stenosis Interruption of the aortic arch
Infant causes of heart failure
High pulmonary blood flow:
Ventricular septal defect
Atrioventricular septal defect
Large persistent ductus arteriosus
Causes of heart failure in older children/adolescents
R or L heart failure:
Eisenmenger syndrome
Rheumatic heart disease
Cardiomyopathy
Initial management of a child with heart failure
Underlying cause treated
General measures:
Bed-rest in semi-upright position
Supplemetal O2 (not in L-R shunt)
Sufficient calorie intake
Diuretics & ACEI (captopril): R-L shunt & high pulmonary flow
Beta-blockers and digoxin: to be considered
Prostaglandin infusion to keep ductus arteriosus patent in duct dependent lesions
Key features of a pathological heart murmur
Diastolic or pansystolic Late systolic Loud murmurs >grade 3/6 Continuous murmurs Associated with cardiac abnormalities Abnormal signs and symptoms: SOB, fatigue, failure to thrive, cyanosis, clubbing, hepatomegaly
Innocent heart murmur characteristics
Systolic Short duration & low intensity Intensifies with increased cardiac output: exercise/fever May change intensity with posture/head position No associated thrill/heave No radiation Asymptomatic patient Left sternal edge
Types of innocent heart murmur
Venous hum: ‘machinery’ quality sound, upper left sternal edge, due to blood flow in great vessels
Flow murmur: short systolic murmur, mid left sternal edge, often heard during acute illness with fever
Musical murmur: systolic murmur, lower left systolic edge
Features of a venous hum
Common and harmless
Heard above right clavicle and over right jugular vein flow of blood causes the vein wall to vibrate causing a humming
Hum is heard throughout cardiac cycle
Placing finger on jugular vein will abolish the sound
Murmur may disappear if patient is supine or if the patient turns their head to one side
Types of left to right shunts
Atrial septal defects
Ventricular septal defects
Persistent ductus arteriosus
What are the 2 main types of ASD
Secundum ASD (80%): defect in the centre of the atrial septum involving the foramen ovale
Partial atrioventricular septal defect (pAVSD) defect of the atrioventricular septum characterized by:
Inter-atrial communication between bottom end of atrial septum and atrioventricular valves (primum ASD)
Abnormal atrioventricular valves, with L atrioventricular valve with 3 leaflets and often regurgitates (regurgitant valve)
ASD clinical features
Often asymptomatic
Recurrent chest infections
An ejection systolic murmur heard on ULSE due to increased flow across pulmonary valve
Fixed and widely split 2nd heart sound: due to right ventricular stroke volume being equal in both inspiration & expiration
With pAVSD apical pansystolic murmur from atrioventricular valve regurgitation
Small VSD clinical features
Smaller than the aortic valve in diameter (<3mm)
Asymptomatic
Loud pansystolic murmur at LLSE & quiet pulmonary 2nd sound
Large VSD clinical features
> 3mm
Heart failure with breathlessness and failure to thrive after 1w
Recurrent chest infections
Heart failure signs: tachypnoea, tachycardia, hepatomegaly
Active precordium: heave
Soft pansystolic murmur/no murmur (implies larger defect)
Apical mid-diastolic murmur: increased flow across mitral valve
Loud pulmonary 2nd sound: raised pulmonary arterial pressure
Persistent ductus arteriosus pathophysiology
The ductus arteriosus connects the pulmonary artery to the descending aorta it normally closes shortly after birth
In PDA it still hasn’t closed by 1 month old
The flow of blood across a PDA is from the aorta to the pulmonary artery (L-to-R) following the fall in pulmonary vascular resistance after birth
Persistent ductus arteriosus clinical features
Most present with a continuous murmur beneath the clavicle as the pressure in the pulmonary artery is lower than the aorta throughout the cardiac cycle
Pulse pressure is increased: collapsing/bounding pulse
Symptoms are unusual, however if large:
Increased pulmonary blood flow –> heart failure and pulmonary hypertension
Atrioventricular septal defect pathophysiology
Complete AVSD these is a large defect often found in the middle of the atrial septum down to the middle of the ventricular septum
No separate mitral and tricuspid valve: common atrioventricular valve of 5 leaflets guarding the atrioventricular junction
As there is a large defect there is pulmonary hypertension
Trisomy 21 with AVSD: complete AVSD is often found in conjunction with Down syndrome
Atrioventricular septal defect clinical features
Presentation on antenatal ultrasound screening o Cyanosis at birth or heart failure at 2-3 weeks of life
No murmur heard
The lesion can be detected on routine echo screening in a newborn baby with Down’s syndrome
Atrioventricular septal defect management
Small VSDs close spontaneously and is investigated via the disappearance of the murmur
Prevention of bacterial endocarditis: good dental hygiene
If large VSD:
Treat heart failure medically: diuretics & captopril
Surgical repair at 3-6m
AVSD features on ECG and CXR
CXR: Enlarged heart, enlarged pulmonary arteries, increased pulmonary vascular markings
ECG: negative deflection in aVF