See Practical for ECG reading, and ABC of ECG.
Starling curve - Cardiac output vs filling pressure. Rises in linear fashion initially, then levels out and drops.
Situs = pattern of chambers. Solitus is normal. Atria characterized by different appendages hence isomerism (=mirror images, can have 2 "right" or 2 "left"). Isomerism associated with midline liver, malrotated gut, identical lung lobes and bronchial structure (1st branch before/after lower lobe artery).
Aorta and IVC usually opposite sides. IVC usually posterior - if not, probably azygous vein.
Coarse trabeculation in RV, fine in LV. Size not useful eg HLHS.
Arterial trunks distinguished only by branching pattern.
Overriding valve is one that lies over a septal defect; chordae may all attach to 1 ventricle else straddling. If overrides more than 50% then termed double outlet/inlet.
Transposition is bad term - spectrum of rotation, better to specify the precise concordance of atria & ventricles, arterial trunks & ventricles.
Myocardial function: usually expressed as LV ejection fraction, as assessed on M-mode. But not very reproducible, and in neonates dependent on ductal flow. Tissue Doppler imaging uses Doppler gate at left and right ventricular wall and at septum to give myocardial velocity.
Balloon valvuloplasty is choice for pulmonary stenosis, except Noonan's where the ring is dysplastic and a patch is required to enlarge the annulus. Can even be done in pulmonary atresia, by fist perforating the valve with a hot wire. Useful in Fallots to relieve cyanotic spells as prelude to repair. Also choice for aortic stenosis, coarctation (but beware associated hypoplasia of LV/arch). Amplatzer devices (shaped mesh) used to occlude ASD, PFO, PDA and VSD, especially multiple defects which are difficult to repair surgically. Perimembranous defects are more difficult because aortic valve function may be affected: new devices have eccentric disks to avoid this problem. Coil occlusion for AV malformations. BMJ - ABC of interventional cardiology
Definite=2 major, or 1 major +3 minor. Possible=1 major+1 minor, or 3 minor. Vascular phenomena include:
Differential of vegetations: Libman Sacks (SLE - broad based, don’t wave in the breeze), marantic (malignancy), myxomatous.
Immunological phenomena include splenomegaly, glomerulonephritis and systemic vasculitis eg skin purpura, hypergammaglobulinaemia, cryoglobulinaemia, low C3.
Take multiple blood cultures. The positive predictive value of echocardiography is poor when there is no clinical evidence to support the diagnosis of endocarditis! Vegetation on a line or device can be sterile or infected, imaging will not distinguish - examine whole course of line. TOE for inadequate thoracic views or problematic cases. Periannular abscess is serious - potential for fistula between 2 compartments, else rupture through conducting system - hence indication for surgery.
Viridans streptococci (as found in the mouth) still the most common organisms, but the spectrum of organisms responsible for the disease is becoming more diverse and staph in particular is becoming more common. This change is probably due to increasing numbers of critically ill neonates/kids getting central lines, in addition to the expanding group of pediatric patients surviving cardiac surgery.
Echo shows endocardial involvement in 11% of children with S. aureus bacteremia, so not surprising IBE develops in the presence of plastic.
Those with central lines will tend to get right-sided endocarditis, with no peripheral embolic phenomena. Symptoms tend to be mild but there is persistent bacteremia despite ongoing appropriate antibiotic treatment.
Treatment is difficult because the fibrin meshwork of the vegetation protects bugs not only from antimicrobial agents but also the host's immune defences. Secondly, susceptibility to antibiotics may be less because the dense concentration of bugs in the vegetation can force them into a slowed state of cell division, which reduces the window of opportunity for drugs that work at just one stage of the life cycle.
Thus, highly susceptible in vitro may not reflect in vivo. Equally, defervescence is usually quick but Staph aureus is well recognized as taking up to 2/52 to respond to appropriate antibiotics. Beware abscess, drug fever. Do surveillance cultures.
If considering, change warfarin to heparin. Required in children with intracardiac abscess, severe valvular regurgitation and infected prosthetic material. Otherwise, use high concentration of bactericidal (not bacteriostatic) therapy over an extended period of time. Surgery appears to confer a better prognosis in cases with heart failure.
MIC is vaguely useful - but remember too that efficacy for time-dependent drugs (eg penicillins) is dependent on the duration of contact between the drug and the bug. So use high doses at short intervals ie 4-6hrly. Concentration-dependent drugs (eg aminoglycosides) work best at higher concentrations - still debate about optimal frequency viz once daily vs conventional administration).
Most strains of viridans streptococci are highly penicillin susceptible (MIC <0.1 mcg/ml) and monotherapy with penicillin or ceftriaxone for 4 weeks is effective. Adding gentamicin for the first 2 weeks of treatment has been associated with more rapid sterilisation of the vegetation.
For viridans streptococci with intermediate penicillin susceptibility (MIC >0.1 mcg/ml but <0.5 mcg/ml) give penicillin for 4 weeks plus gent for 2 weeks.
If penicillin resistant (MIC >0.5mcg/ml) use 4-6 weeks ampicillin or vanc plus gent.
Where 4-6 weeks treatments suggested, give 4 weeks treatment if symptoms have been going on for <3 months, otherwise 6.
Enterococcus is rare in kids cf older adults, lucky considering it is resistant to cephalosporins, only slightly susceptible to penicillins and usually inhibited rather than killed by vanc and aminoglycosides. So use combination amp or vanc plus gent as above, and look closely at sensitivities. For VRE linezolid is static; quinu/dalfupristin may or may not be sensitive. Needs 8+ weeks!
Staph without prosthetic valve - give fluclox 4-6 weeks plus gent for 3-5 days. Else vanc (monotherapy), but fluclox works faster. If prosthetic, needs at least 6 weeks fluclox and rifamp (oral), plus 2 weeks gent (prevents resistance to rifampicin developing, and covers MRSA too). Not a huge amount of evidence to support this, however.
HACEK organisms are slow-growing Gram negative bacteria that form a normal part of the human flora esp in the mouth:
Most common cause of Gram-negative endocarditis in children, and probably responsible for a lot of culture negative cases (which make up 10-30% of total). They have a propensity to form friable vegetations (especially H. parainfluenzae) that break off and cause symptomatic emboli. May well involve previously normal hearts. Mostly resistant to penicillin so use cephalosporin monotherapy 4/52.
Strep pneumoniae more common in kids but still rare. High mortality even where nominally susceptible. Resistance in other countries is a big problem. 4 weeks ceftriaxone or vanc.
Anaerobes and fungi possible esp ITU. Fungal will always need surgery, and probably need lifelong prophylaxis. Q-fever - 4 YEARS of doxy + septrin/rifamp. Just about any bug possible! A significant minority will remain undefined.
Although oral therapy has been shown to be effective in certain situations, most would use parenteral to ensure good levels and compliance. Changing to oral later is certainly a viable option in uncomplicated, responsive cases.
Current Opinion in Cardiology (adults)
No trials of prophylaxis! Amoxicillin good against oral streps. Azithro better than erythro - better tissue penetration, tolerance, longer action. Clindamycin is an alternative.
Previous rheumatic fever or Kawasaki's without valvular dysfunction considered not to be at risk. High risk includes:
But most cases have no such history of course, and toothbrushing is likely to be a much more important cause. Regular antibiotics rapidly induce resistance in viridans strep so not much you can do.
Pediatric Drugs, 2001, vol. 3, issue 10, p 703
Inflammation of the myocardium, usually viral. A common cause of sudden unexpected death.
After virus entry into myocytes, Natural Killer cells attack infected cells. Knock out mice with limited NK function get more severe disease. Infiltration by CD4 cells and CD8 cells with release of inflammatory cytokines is what probably causes the most myocardial damage.
Can be non-specific, with fever and fatigue. Arrhythmia causing palpitations or even sudden death may occur abruptly. Disproportionate tachycardia is a major clue before onset of signs of heart failure viz breathlessness, pallor, sweating. Clinically there may be muffled heart sounds, a hyperdynamic precordium, a gallop rhythm besides other features of heart failure eg high jugular venous pressure, basal crepitations.
Supportive.
Trials of steroids, ciclosporin and azathioprine have failed to demonstrate benefit. Intravenous immunoglobulin has been shown to improve cardiac function but is not standard therapy. Pleconaril has been used for Enterovirus meningitis but is no longer available. Other anti-virals have been used where specific infections have been identified eg Cidofovir for adenovirus.
Dilated cardiomyopathy may result from acute mycarditis.
The mainstay of management are mechanical, electrical and pharmacologic agents to support cardiovascular function and to minimize damage. The infectious disease physician must decide whether to recommend immunomodulatory and/or antiviral therapy. The Myocarditis Treatment Trial for adults with histopathologically confirmed myocarditis and compromised cardiac function published in 1995 failed to show significant improvements in ventricular function or survival with prednisone and azathiaprine or cyclosporin. More recently, the presence of adenoviruses or enteroviruses by PCR in myocardia of adults with lymphocytic myocarditis and progressive cardiac failure predicted poor response to 6 months of prednisone and azathioprine treatment. Agents that target inflammatory mediators, such as etanercept, a TNF-[alpha] antagonist, or IFN-[beta], are promising but have not been studied in large trials or in children. Although one study showed good clinical outcomes in children with AM treated with steroids, it was not designed to determine efficacy and safety of this intervention. No data exist to support usage of these therapies in adults or children with viral AM, and agents that interfere with production of neutralizing antibodies may be harmful. Adult and pediatric studies have shown improved cardiac function in AM patients who receive IVIG except in adults with recent onset DCM. Controlled IVIG trials in viral-specific AM or DCM have not been conducted. IVIG appears to be well-tolerated and by enhancing viral clearance or down-regulation of inflammatory mediators is probably beneficial in neonatal and pediatric AM. Pleconaril, an experimental antiviral with broad activity against enteroviruses and rhinoviruses, is available for compassionate use but has not been studied in AM. In adults and children with enteroviral meningitis, it results in faster resolution of symptoms but little to no overall benefit - consider for critically ill children with suspected or proven enteroviral infection. Other antiviral agents (cidofovir for adenoviruses, neuraminidase inhibitors for influenza viruses, gancyclovir for cytomegalovirus) may be useful in confirmed viral cases, but data are lacking, and empirical use for AM cannot be recommended.
PIDJ Vol23(7) July 2004 pp 665-666 Leonard, Ethan G
In the past, TB, rheumatic, uraemia. Now viral (Coxsackie)/idiopathic, bacterial (staph, HiB, strep), connective tissue disease, lymphoma. Bacterial is usually be contiguous spread from lung focus, but rarely by haematogenous spread (eg osteomyelitis) or spread from peritoneum.
Effusion presents with breathlessness and big heart, as CCF - but lungs are clear clinically and on CXR. Pericarditis presents with chest pain (radiates to left shoulder, eased by sitting forward). Pulse pressure may be low, heart sounds may be muffled, but no murmur or gallop. JVP will be high but possibly invisible eg >20cm. ECG shows classically saddle shaped ST elevation but may just be elevated. Complexes may be small. May be difficult to distinguish from myocarditis.
Exudate has protein >50%, LDH>60%, gluc<100% of serum value. Else transudate (incl uraemia, hypothyroidism).
Crucially, treatment is different from that for CCF - give fluids (diuretics make worse), drain. Tamponade occurs if rate of fluid accumulation is excessive - volume is not important. Signs as above but also pulsus paradoxus (>10mmHg drop in systolic BP; else vanishing pulse during inspiration).
Heart size may be normal in constrictive pericarditis, but symptoms of tamponade.
Consider associated pneumonia, meningitis, osteomyelitis.
Accessory pathways the usual reason, esp infants, but nodal reentrants quite common in older kids. Get a 12 lead before doing anything unless absolutely impossible.
An accessory pathway may conduct a normal QRS but more usually a delta wave will be seen. If retrograde conduction, then inverted P wave seen immediately after the QRS. If a nodal reentrant, P wave is subsumed into QRS complex.
Vagal manoeuvres do work, but carotid sinus is the least effective. Older kids can stand on their hands! If dunking in cold water, Karen Macleod counts to 5. If adenosine doesn?t work:
Digoxin is good for babies and infants but needs 2 loading doses 6 hours apart, and you may not get a result until then. Propanolol is contraindicated in asthma. Verapamil is contraindicated under 1 year as it is negatively inotropic and can cause arrest.
SVT usually settles down by 6-12 months but may recur around the age of 8yrs. Onset outside infancy will probably not resolve spontaneously. Prevention needs to be discussed: some families will be happy just treating episodes as they occur. Otherwise use digoxin in infancy to prevent, propanolol later.
Rare forms:
May be SVT with aberrant conduction, WPW with Atrial fib? Walking p wave indicates AV dissociation. Otherwise give adenosine to terminate SVT or reveal P waves (increases block).
Check electrolytes and gas. Amiodarone if DC shock resistant. Don't sync the DC shock if R waves small. Atrial fibrillation needs high dose, same as VF.
Radiofrequency Ablation - good for cardiomyopathy due to tachy, WPW with Atrial Fib (danger of sudden death). Ideally age over 6yr.
Brugada syndrome – RBBB and ST elevation in V1-3. Associated with VF and sudden death in young men esp SE Asia. Many genetic mutations associated but most patients with a mutation don't get the syndrome.
Often drug-induced, but can be congenital. Various gene mutations and polymorphisms are described for a range of genes (LQTS 1-8) that code for different ion channels so affect repolarization. Yet many carriers have normal QT so asymptomatic. It is likely that for some of these people, multiple repolarization challenges are needed before their long QT becomes unmasked. Drugs, bradycardia and electrolyte abnormalities are the most common of these challenges.
Hence the QT at rest is not always reliable. Check family history of congenital deafness (association seen in Jervell and Lange Nielson syndrome (JLN)) or sudden death, episodes of syncope, other T wave abnormalities.
Not uncommonly misdiagnosed as epilepsy, which then delays real diagnosis (but ?channelopathy in brain as well as heart!) Ann Emerg Med. 2009 Jul;54(1):26-32. PMID 19282063
Generally associated with a heave, single S2 and murmur; cyanosis may be subclinical, sats may even be normal eg TGA with VSD. Degree of cyanosis depends on amount of pulmonary blood flow.
Also known as TCPC, or total cavo-pulmonary connection. Done to increase flow to lungs, but results in single circulation with lung perfusion occurring passively, at low pressure.
First stage is usually modified Blalock-Taussig (BT) shunt ie conduit between subclavian artery and pulmonary artery (modified means subclavian artery is not taken down).
The shunt but be restrictive, ie pulmonary flow should not be excessive (which would lead to pulmonary hypertension, in which case Fontan repair would be impossible since there would be no flow into lungs. A low diastolic BP suggests excessive shunt, with run off into the lungs.
Second stage is bidirectional Glenn procedure, in which SVC is separated from atrium and plumbed into pulmonary artery. BT shunt is usually taken down at this time. Bidirectional because right and left. Load on ventricle is thus reduced, although cyanosis is not fully corrected as blood in IVC still returns to systemic circulation.
Final stage is to put in conduit from IVC to pulmonary artery. The pulmonary artery is disconnected from the heart. Actually an extracardiac conduit, to avoid problems of stitch failure or atrial ballooning. Risk of thrombosis so usually warfarinized.
Prognosis is uncertain - 2 open procedures impacts on cognition (but potential for transcatheter procedures), end organ damage caused by chronic hypoperfusion. But better surgical techniques. Quality of life indicators suggest post Fontan patients are no different from normal population! IQ reduced by 10 points.
Defined as any arrangement of organs along the left-right body axis that differs from complete situs solitus or complete situs inversus, ie do the heart and liver lie on the same side or not? If not, associated with Intestinal rotational abnormalities esp malrotation, predisposing to midgut volvulus. Also associated with polysplenia or asplenia.
Probably no need to screen for upper GI probs - in case series, less than 1% developed malrotation.Archives of Disease in Childhood 2005;90:813-815
Present with spells - episodic increase in stenosis (mech? infundibular spasm?) causing increase in right sided pressure hence shunt to left with cyanosis. Older child will often squat in order to increase left sided resistance and hence reduce shunt. Management:
Catecholamines appear to worsen!
To fix, patch/stitch VSD and expand pulmonary artery. Tend to have stiff RV post repair so poor LA filling and poor function. Transannular patch assoc with progressive RV dysfunction and higher mortality - 2 patches, 1 above & 1 below better?
See Vasculitis.
Midaortic syndrome (type of fibromuscular dysplasia) diagnosed on MR Angiography. Usually young adults but seen in neonate onwards. Associated with Williams syndrome.
See Infections for diagnosis and management.
A pancarditis is seen. The mitral valve is most commonly affected, followed by the aortic. The initial murmur may be due to mitral regurgitation, and/or dilation of the valve ring (or may be related to tachycardia alone!). Pericarditis never occurs in isolation.
Mitral regurgitation may improve over time to a degree; aortic regurgitation does not.
The commonest congenital heart defect – 1-2% of population. 30% will at some point in their lifetime have a serious complication viz stenosis/regurgitation, IBE, aortic dissection. May be responsible for more deaths/morbidity than all other congenital defects combined!!!
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