Cardiology Flashcards
What cardiac murmurs present in the first 24hrs of life?
- Semilunar valve stenosis (AV/PV)
- AV valve regurgitation (MR/TR)
NOT: VSD, ASD
What CHD causes cyanosis in the first 24hrs of life?
TGA Single ventricle physiology
What CHD presents as critically ill in the first 24hrs of life?
Valve regurgitation – especially Ebstein’s [large RA], absent PV Obstructed TAPVD “Early” duct dependent presentation
CDH dependent on PDA for pulmonary blood flow
Severe cyanosis when duct closes Critical PS Pulmonary atresia Single ventricle with PS or PA
CDH dependent on PDA for systemic blood flow
Low CO when duct closes Critical AS Critical coarctation HLHS
CDH dependent on PDA for mixing
TGA
CDH that causes massive cardiomegaly in neonate
Ebsteins
CDH that causes the snowman sign
TAPVD
Asymptomatic murmurs
“Functional” commonest ASD VSD PS + AS (ejection click) Coarctation: murmur best heard at the back PDA
What valvular problem is associated with coarctation
Bicuspid aortic valve
Can you eliminate a ‘stills murmur’ with positioning?
Yes, ask the child to sit on the bed with their neck hyperextended + propped up on their arms positioned behind them
Ficks principle
Total uptake (or release) of a substance by an organ is the product of blood flow to that organ and the concentration difference of the substance in the arteries and veins leading into and out of that organ Key rules 1. The lower the CO the more oxygen is extracted 2. High mixed venous sat = shunt (eg. TAPVR) 3. Low mixed venous sat = low CO Normal mixed venous = 75 (high 60’s-75)
Ficks formula
Fick’s method = O2 consumption/ (arterial – venous content difference) → This requires Hb, saturation of O2, O2 binding capacity of Hb and dissolved O2 Qp/Qs = arterial saturation – mixed venous saturation / pulm venous saturation – pulmonary artery saturation QP: QS = 1 no shunt Qp: QS > 2 = large shunt Qp: QS < 1 R to L shunt
What is the formula to calculate pulmonary vascular resistance?
PVR (um2) = mean PA pressure - LA pressure / Qp Qp = pulmonary blood flow LA pressure can be inferred by using PCWP (pulmonary capillary wedge pressure) IF there is no shunt you can use CO as a surrogate for Qp 1-2 = normal 2-4 = mild elevation 4-6 = mod elevation >7.9 = severe, high correlation with irreversible PVR PVR = 1/6th of SVR
Criteria to refer VSD to cardiology
Heart failure FTT Dominant RVH on ECG (suggests tetralogy or variant) Isolated LVH (suggests coarctation or PDA) Aortic regurgitation Qp/Qs > 2: indication to close
Classic triad of symptoms in aortic stenosis
Chest pain Shortness of breath Syncope
Normal pressures in the heart
Right atrium (mean) 2-8 Right ventricle (peak) 17-32 Pulmonary artery (mean) 9-19 >25 = PHTN Left atrium (mean) 2-12 Left ventricle (peak) 90-140 Aorta (mean) 70-105
Pulmonary hypertension
Mean PA pressure > 25mm Hg at rest Mean PA pressure > 30mm Hg with exercise
What is the formula for cardiac output + what are the methods of measurement (direct vs indirect)?
CO = HR x SV Normal CO varies with age (higher in newborns) Children 4-5L/min/m2 In the absence of any shunt, pulmonary flow + CO are the same Direct measurement = thermodilution, indicator dye dilution Indirect measurement = fick method (requires estimation of O2 consumption)
Is clinical cyanosis noted earlier in anaemia or polycythaemia?
Polycythaemia Cyanosis is recognised at a higher level of O2 saturation in polycythaemia (80-85%) and low level of saturation in anaemia (45-50%) Clinical cyanosis is reached when level of reduced HgB reaches 5g/100mL (normal = 2g /100mL)
What factors increase PVR?
Hypoxia Hypercapnia Increased sympathetic tone Polycythaemia Pulmonary emboli Pulmonary oedema Lung compression (effusion)
What factors reduce PVR
Oxygen Adenosine Inhaled NO Prostacyclin Ca channel blockers
% of CHD associated with extra cardiac anomalies
10-15%
Risk of recurrence of CHD in siblings
2-4 % Further increased risk if > 1 sibling affected or if maternal history
Diagnostic criteria for Kawasaki disease
WARM CREAM Fever for > 5 days AND 4 out of 5 of the following Conjunctivitis (bilateral, dry or non-purulent, preferentially in bulbar distribution) Rash (Polymorphous, without vesicles, bullae or crusts, occurs in the first few days. Variable such as urticarial morbilliform, maculopapular or resembling scarlet fever) Extremity changes (hyperaemia and painful oedema of hands and feet that progresses to desquamation in the convalescent stage; perianal desquamation) Adenopathy (cervical, most commonly unilateral, tender, at least one node >1.5cm) Mucosal involvement (intense hyperaemia of lips leading to redness and cracking and/or diffuse erythema or oropharynx; strawberry tongue)
Kawasaki disease fast facts
2nd most common vasculitis in childhood after HSP Most common cause of acquired heart disease in children 85% of cases < 5yrs (peak 18-24 months) Rare in children < 6 months + > 5yrs BUT more likely to develop CAA More common in Asian population 15-25% develop CAA if untreated compared to 4% if treated with IVIG CAA rarely occurs before day 10
Incomplete Kawasaki disease criteria
Children with fever for 5 days + 2 clinical criteria OR fever for 7 days without explanation AND - CRP > 8 + ESR > 20 AND 3 or more: - Anaemia - Plt > 450 after 7th day of fever - Albumin < 30 - Raised ALT - WCC > 15 - Urine > 10 WBC/hpf OR positive echo
Management of rheumatic heart disease
Rest, fluid restriction Diuretics ACEI for afterload reduction if aortic regurgitation Digoxin for SVT No literature evidence for use of corticosteroids and IVIG. However, corticosteroids used commonly if severe
Diagnostic criteria of rheumatic fever
Evidence of strep A infection (elevated or rising ASOT or anti-DNAseB or positive throat culture / rapid antigen / PCR test) AND 2 major OR 1 major + 2 minor MAJOR Joints (polyarthritis or aseptic monoarthritis or polyarthralgia. Usually migratory + asymmetical). Large joints most commonly affected; especially knees + ankles. Should respond to NSAIDs. HEART (carditis, subclinical evidence of rheumatic valvulitis on echo) Nodules (subcutaneous, extensor surfaces). Very rare <2% of cases BUT highly specific. Round, firm, mobile + painless. Strongly associated with carditis. Erythema marginatum. Very rare <2% of cases BUT highly specific. Sydenham chorea (jerky, uncoordinated movements). Predominately affects females in adolescence. Disappears in sleep. MINOR PR prolongation Elevated temperature Arthralgias CRP > 30 ESR > 30
Antibiotic treatment for strep A sore throat / tonsillitis
Benzathine benzylpenicillin IM once OR Phenoxymethylpenicillin 15mg/kg BD for 10 days OR Cefalexin 25mg.kg BD for 10 days OR Azithromycin 12mg/kg daily for 5 days
What are the upper limits of normal for PR interval?
3-11yrs 0.16 12-16yrs 0.18 17+yrs 0.2
Fast facts about sydenham chorea
- May occur after a prolonged latent period following strep A infection (must exclude SLE or chorea gravidarum first) - Diagnosis of ARF can be made without the presence of other manifestations or elevated plasma strep antibody titres if chorea present - ARF manifestation that is most likely to reoccur - May occur in pregnancy or with OCP use - Majority of cases resolve within 6 months - Higher prevalence of ADHD, anxiety, depression + cognitive dysfunction after recovery
Predominantly manifestation of ARF carditis
Myocarditis and pericarditis may occur in ARF however, the predominant manifestation of carditis is the involvement of the endocardium presenting as a valvulitis, especially of the mitral and aortic valves. The incidence of carditis in initial attacks of ARF varies between 30% and 82%
What valve does ARF commonly affect?
Valvulitis most commonly affects the mitral valve, leading to mitral regurgitation (MR), although with prolonged or recurrent disease scarring, may lead to stenotic lesions. MR presents clinically as an apical blowing, holosystolic (pansystolic) murmur. The presence of an associated mid-diastolic flow murmur (Carey Coombs murmur) implies significant mitral valve regurgitation; however, it must be differentiated from the diastolic murmur of mitral stenosis (MS), which is often preceded by an opening snap