Cardiology Flashcards
Acute Treatment SVT
asymptomatic: usually revert spontaneously
symptomatic: attempt vagal, IV adenosine, CCB
if shocked: synchronised shock
Adenosine
receptors: AV nodal tissues, vascular SM
mechanism: activates K+ channels and hyperpolarises cells
use: SVT (slows AV conduction and breaks reentry in AVRNT)
properties: short half life
SE: vasodilations, hypotension, flushing, dyspnoea, chest pain
Allagille’s Cardiac
85% peripheral artery stenosis
Anginal therapy
mechanisms:
- decrease oxygen consumption
- increase blood flow
drugs:
- nitrates: increase NO in vascular SM, increase cGMP and cause relaxation
- beta 1 receptor blocker: decreased ionotropy/chronotropy
- calcium channel blocker: coronary artery vasodilator
Antiarrythmics
class I: Na channel blockers
class II: beta blockers
class III: K channel blockers
Class IV: calcium channel blockers
Antihypertensive drugs
ACEi “prils”
- mechanism: inhibit conversion angiotension I to angiotensin II with increased bradykinin
- SE: hyperkalaemia, decrease GFR, crosses placenta, cough, oedema
Angiotension II Receptor Blockers “sartans”
- mechanism: block activation ARII receptors
- SE: hyperkalaemia, crosses placenta
Effects:
- decrease SNS
- decreased Na/Cl reabsorption
- decreased ADH secretion
Aortic Arch anomalies
-associated disorders-
Marfan’s syndrome: MV prolapse, aortic aneurysm
Ehler-Danlos: aortic root dilatation
Aortic Stenosis
incidence: 5% CHD
pathogenesis: failed development 3 leaflets
types: valvular 70%, supra 7%, sub 15%
physiology: high pressure LV with hypertrophy
clinical: chest pain on exertion
ECG: LVH
mumur: systolic right 2nd ICS radiation to neck
treatment: surgical (sub/supra), balloon dilation (valvular)
Atrial Fibrillation
incidence: rare in children
pathogenesis: absence of SA stimulus with rapid electral discharges of atria producing fibrillation
RF: large atria, WPW, cardiac surgery
treatment: rate then rhythm control
Atrial flutter
pathogenesis: reenterant rhythm from single focus in RA and circles triscuspid annulus
ECG: uniform, HR 250-300, AV node transmits every 2-4 atrial beat
RF: CHD, intra-atrial surgery
treatment: drugs to slow rate
- non-dihydropyridine CCB: verapamil, diltiazem
- beta blocker
Atrial Septal Defect
ASD
incidence: 10% CHD, F>M
pathogenesis: 50% in association other CHD
types:
- ostium secundum (70%): site of FO
- ostium primum (30%): level TM/MV
- sinus venosus (10%): entry SVC into RA
- coronary sinus ASD: defect in coronary sinus
- PFO
clinical: symptomatic if large, RA/RV enlargement
ECG: RAD, RVH
mumur: widely split S2, systolic mumur
treatment:
- <3mm 100% close spontaneously
- 3-8mm 80% close by 2 years
- large closed with device
Atrioventricular Nodal Re-entry Tachycardia
AVNRT
incidence: mainly adolescents
pathogenesis: 2 pathways within the AV node
clinical: syncope with exercise/stress
treatment: beta blockers, ablation
Atrioventricular Re-entry Tachycardia
AVRT
incidence: 90% SVT in children
clinical: acute onset/cessation at rest or in illness
pathogenesis: normal circuit and accessory pathway
variants
- retrograde accessory
- bidirectional accessory
- antegrade accessory
Atropine
mechanism: muscarinic receptor antagonist causing PNS block and increased AV node conduction
use: heart block, bradycardia
SE: dry mouth, constipation, urinary retention
Brugada Syndrome
incidence: 3/1000, M>F, asians, presents in 30’s but 2-77yrs
cause: AD, mutation SCN5A gene producing sodium channel causing phase 2 reentry
diagnosis: permanent or transient ECG changes
- type 1 (20-25%): SCN5A with RBBB, ST elevation V1-V3
- type 2: GPD1L with <2mm saddleback ST elevation
- type 3: CACNA1c with type 1/2 ECG changes
clinical: recurrent syncope, arrythmia, sudden death
treatment: quinidine, defibrillation
Calcium Channel Blockers
non-dihydropyridine vs dihydropyridine
dihydropyridines (amlodipine, felodipine, nifedipine)
- reduce SVR and arterial pressure
non-dihydropyridines (verapamil, diltiazem)
- myocardium selective
- decrease oxygen demand and reverse coronary vasospasm
Cardiac Axis
Cardiac Glycosides
- digitalis/digoxin-
use: CHF/arrhythmias
mechanisms:
- digitalis: inhibits Na/K ATPase, increased Nai and slows down Ca efflux causing increased contractility and delayed repolarisation
- digoxin: as above, slower 1/2 life
ECG: increased PR (“digitalis effect”), ST segment depression, T wave inversion
toxicity: AV block, VT/VF, nausea/diarrhoea, yellow halows
Cardiac muscle contraction
Cardiac Muscle Depolarisation
Cardiac Tamponade
definition: inadequate cardiac output due to pericardial effusion
pathogenesis:
- acute/subacute accumulation of pericardial fluid causing pressure
- increased diastolic pressure with decreased pulmonary venous return to LA
- collapsed RA/RV
- decreased CO/BP
Cardiomyopathies
definition: intrinsic disease of the heart muscle
types:
- dilated: idiopathic or secondary to infection/disease/cardiotoxic drugs/familial
- hypertrophic: familial with AD inheritance
- restrictive: idiopathic or associated with systemic disease
Cardiomyopathy
associated disorders
DMD
Fabry disease
Hunter/Hurler’s syndrome
Pompe disease
CHF therapy
ASPECTS
Afterload reduction: ACEo, ARBs, BNP, milrinone, nitrates
Sympathetic inhibition: beta blockers, BNP, digoxin
Preload reduction: BNP, diuretics
Enhanced contractility: digoxin
Cardiac remodelling prevention: spironolactone
Timely surgery
Systemic disease treatment
Class Ia antiarrhythmics
Na channel blockers
drugs: quinidine, procainamide
mechanism: moderate Na channel blockers
- non-specifically block K channels and slow repolarisation
- prolongs depolarisation/repolarisation/QRS/QT
use: atrial/ventricular arrhythmias
SE: agranulocytosis, thrombocytopaenia, tinnitus, torsades, hypotension, rash
Class Ib antiarrythmics
Fast Na channel blockers
drugs: phenytoin, lignocaine
mechanism: block fast Na channel
- decreased AP/QT duration
- no effect refractory period
use: VT (ischaemic arrhythmias with fast HR)
SE: bradycardia, HB
Class Ic antiarrythmic
Slow Na channel blocker
drugs: flecainide, encainide
mechanism: blocks slow Na channels
- slow phase 0 depolarisation
- prolongs QRS
use: suppression of PVC, last resort in normal heart
CI: previous MI/VT
Class II Antiarrhythmic
Beta blocker
drug: propranolol, metoprolol, atenolol
mechanism: decrease SNS activity to heart by beta 1 receptor
- decrease cAMP/depolarisation/repolarissation
- decreased conduction through AV
use: SVT, CHF
SE: bradycardia, AV block, CHF, impotence, bronchospasm
Class III antiarrhythmic
K channel blocker
drugs: amiodarone, sotalol
mechanism: K channel blocker
- normal QRS, increased QT
use: WPW, VT/AF, unstable VT
SE: torsades, pulmonary fibrosis, photodermatitis, hepatotoxicity, thyroid issues, corneal deposits
Class IV antiarrhythmics
Ca channel blocker
drugs: diltiazem, verapamil
use: SVTs
mechanism: decrease SA/AV node automaticity
- prolong depolarisation/repolarisation
- increase PR interval
SE: CHF, AV block, flushing, headache, gingival hyperplasia
Classification CHD
Classification Congenital Heart Disease
Stenotic: AS, PS, CoA
Right to Left: TOF, TGA, TA
Left to Right: ASD, VSD, PDA
Mixing: truncus, TAPVR, HLH
Coarctation of the aorta
incidence: 10% CHD, M>F, 70% with bicuspid aortic arch
pathogenesis: constriction aorta at any point
- 98% below left SCA at origin of ductus arteriosus
clinical: difference pulses UL/LL, femoral-radial delay, LL hypoperfusion, BP high in UL and low in LL
- poor feeding, respiratory distress, CHF, acidosis
CXR: notching of inferior border of ribs by enlarged collaterals
ECG: RVH, cardiomegaly, pulmonary oedema
treatment: end to end anastomosis
prognosis: HTN, CVD, re-coarctation, stroke, aneurysm, endocarditis
Complete endocardial cushion defect
AVSD
incidence: 2% CHD, 70% with T21
pathogenesis: failured fushion of upper/lower endocardial cushions with primum ASD/inlet VSD
associations other CHD: TOF, DORV, TGA
clinical:
- shunts left to right with AV regurgitation
- hyperactive precordium, systolic thrill/mumur, mid diastolic rumble
- CHF
ECG: LAD, prolonged PR, RVH, LVH
CXR: cardiomegally, increase pulmonary markings
treatment: surgery at 2-4 months with patch closure
Complete Heart Block
acquired: post cardiac surgery, post myocarditis, drugs, rheumatic fever, cardiac tumour
congenital: AI 70% (neonatal lupus), gene mutation, complex structural disease (TGA)
clinical: cardiomegally, CCF
examination: prominent peripheral pulse, systolic mumur left sternal edge, variable 1st heart sound
ECG: prolonged QRS duration with slow ventricular rate as pacemaker is below the bundle of his
treatment: indication for pacemaker
- CCF, long QT, bradycardia, wide QRS, exercise intolerance
Congenital rubella
-cardiac issues-
35% cardiac anomalies
- PDA, PA stenosis, ASD, VSD
Coronary artery fistula
incidence: most common CA anomaly (50%)
pathogenesis: R>>L, most terminate right side of heart (40% RV, 30% TA, 20% PA)
types:
- branching tributary: from CA along normal distribution 7%
- abnormal CA system with aberant termination >90%
clinical: usually asymptomatic
- CHF if left to right shunt is large
management: ligation
Cyanotic Heart Diseases
- Tetralogy of fallot
- Transposition of the great arteries
- Tricuspid atresia
- Truncus arteriosus
- TAPVD
DiGeorge syndrome
-cardiac issues-
TOF
Diuretics
thiazide
mechanism: inhibit NaCl reabsorption in DT
SE: hypokalaemia, hyponatraemia, acidosis, hyperglycaemia, hypercalcaemia
loop diuretics (frusemide)
mechanism: inhibit NaK2Cl transported in thick ascending LOH producing PG
SE: nephritis, ototoxicity, hypokalaemia, hypocalcaemia, alkalosis, increased uric acid
K-sparing diuretics (spironolactone, amiloride)
mechanism: aldosterone receptor antagonist OR Na channel blocker
- decreased reabsorption of Na and influx of K
side effect: gynaecomastia, hyperkalaemia
Double outlet right ventricle
pathogenesis: aorta and PA both originate RV
- blood shunts across VSD to reach great arteries
- PA circulation under high pressure
subtypes:
- sub-aortic VSD
- sub-pulmonary VSD
- doubly commited VSD
- non-commited VSD
Ebstein’s anomaly
incidence: <1% CHD
pathogenesis:
- downward displacement of TV into RV causing RV hypoplasia
- TV regurg due to dilated/hypertrophic RA
- decreased CO
- required interatrial communication in ALL cases
clinical: cyanosis, dyspnoea, HUGE cardiomegally, CHF, HM, SVT
mumur: TR mumur, wide split S2
ECG: RAH, RBBB, 1st degree block, WPW in 20%
CXR: balloon shaped heart, decreased pulmonary markings
treatment: TV repair and fontan procedure
prognosis: 19% die neonatally, 30% before 10 yrs
Eisenmenger syndrome
pathogenesis: left to right cardiac shunt with subsequent pulmonary HTN
- eventual reversal of shunt causes cyanosis
associations: ASD, VSD, PDA
Fetal circulation
drainage
SVC: drains upper body including brain (15%CO)
IVC: drains lower body/placenta (70%CO)
cardiac circulation
- most SVC and 2/3 IVC goes to RA to RV to PA
- 10% to lungs and 90% to PDA
outflow
- 55% of CO goes to placenta (low resistance)
Fick’s principle
amount of oxygen consumed by body is equal to the AV difference in oxygen content x blood flow (CO)
ie.
CO= oxygen consumption/AV difference
= oxygen consumption/(saturation difference % x oxygen content)
Heart block
1st degree: prolonged PR
2nd degree:
- type 1: progressive prolongation PR until QRS dropped
- type 2: prolonged PR with intermittent QRS dropped
3rd degree: no relationship A/V activity
HOCM
incidence: 0.2%
genetics: AD, 12 genes encoding sarcomere proteins
pathogenesis: disorganised LV architecture
- septal/LV hypertrophy causing dynamic outflow obstruction (30%) and abnormal electrical activity
clinical: syncope, chest pain, palpatations, dyspnoea
examination: LV impulse/lift, systolic mumur, S3/S4, MR mid-diastolic rumble
ECG: deep narrow Q waves in lateral/inferior leads, LAH with p wave changes
CXR: cardiomegally
treatment: medications (beta blockers, CCB), myectomy, ventricular pacing
prognosis: survival 10yrs w/o surgery 61%, with 83%
Hyperlipidaemia drugs
statins (rosuvastatin/atrovastatin/simvastatin)
mechanism: HMG-CoA reductase inhibitor, increased production LDL receptors
SE: myositis, increased LFTs, photosensitivity
fibrates (gemfibrozil/fenofibrate)
mechanism: upregulation lipoprotein lipase and increased clearance TG lipoprotein
SE: myositis, ATN, increased LFTs, cholelithiasis
Niacin:
mechanism: lipolysis inhibition/TG synthesis in adipose tissue
SE: flushing, hyper glycaemia, hyperuricaemia
resins (cholecystyramine, colestipol, colesevalam)
mechanism: bile acid sequesterant preventing intestinal absorption
SE: GI upset, malabsorption, pruritis
Ezetimibe
mechanism: selective inhibitor of dietary cholesterol in small bowel
Hypoplastic Left Heart Syndrome
incidence: 1% CHD, 40% neonatal cardiac deaths
RFs: Turner’s, T13, T18, Jacobsen’s syndrome
pathogenesis: LV and aorta are hypoplastic and unable to support circulation
- RV supplies both pulmonary and systemic circulation
- survival depends on PDA/ASD or mixing
clinical: ill early, cyanosis, resp distress, CCF, HM
examination: NO mumur, single S2, weak pulses, low CO
ECG: RAH/RVH
CXR: pulmonary oedema, right sided cardiomegally
management: PGE1 infusion, surgery
surgery: 1st Norwood (RV to PA), 2nd 3-6 months bidirectional Glenn (SVC to right PA), 3rd 18-30 months Fontann (IVC to PA)
Indications intervention Aortic Stenosis
refer:
- chest pain, SOB, syncope
- asymptomatic but LVH on ECG or ECHO gradient >50mmHg
intervention:
- symptoms or LVH strain or cathether gradient >50mmHg
Indications VSD intervention
1. CHF
2. FTT
3. Aortic regurgitation into VSD
4. Qp/Qs > 2
Interrupted aortic arch
pathogenesis: part of aorta absent causing obstruction blood flow to lower body
clinical: symptoms post PDA closure
treatment: PGE1, end to end anastomosis
Junctional ectopic tachycardia
pathogenesis: abnormal automaticity AV node
- junctional rate>sinus rate and AV dissociation occurs
causes: cardiac surgery, congenital
ECG: narrow QRS, p waves not seen
treatment: difficult
Left atrial hypertrophy
-causes-
- mitral valve disease
- cardiomyopathy
- large PDA/VSD
Long QT syndrome
pathogenesis: prolongation myocardial repolarisation causing refractory areas of myocardium with reentry and VT
causes
congenital (50%): defective ion channels
romano-ward syndrome (AD): syncope with exercise/stress
- KCN/SCN genes coding Na/K channel
jervell and lange-nielson syndrome (AR): bilateral SNHL, syncope with exercise/stress
- KCNQ1/KCNE1 genes encoding K channels
acquired
- antiA (Arrhythmics): amiodarone, sotalol, quinidine
- antiB (AB): erythromycin, clarithromycin, azithromycin, bactrim
- antiC (psyChotics): haloperidol, risperidonse, chlorpromazine
- antiD (Depressant): TCA
- LowEL kiw Ca/K/Mg/thyroid
- AntiF (fungal): fluconazol
- AntiH (Histamine)
- neurological/nutritional/cardiac
clinical: syncope 26%, seizures 10%, palpatations, arrhythmias, cardiac arrest
diagnosis: Schwarz score
treatment: if score <4 or QT>0.47
prognosis: SCD in 50% untreated
Longterm treatment SVT
1st line: beta blockers +/- digoxin
DON’T USE DIGOXIN/VERAPAMIL WPW
2nd line: flecainide (structurally normal), amiodarone (neonates), sotalol, ablation
Magnesium
mechanism: prevents influx Ca and prevents early depolarisation
use: torsades
Management TOF
early: PGE1
late: surgery in 1st year if life
- initial shunt procedure: Blalock-Taussig with right SCA linked to PA
- patch closure of VSD
- enlargement RVOT
Maternal conditions
associated CHD
diabetes mellitus: TGA 5%
rubella: PDA, PA stenosis, ASD, VSD
alcohol: septal defects 30%
phenylketonuria: TOF 25-50%
SLE: CHB 40%
lithium: TV defect 20%
Multifocal atrial tachycardia
definition: >3 ectopic p waves with varying PR intervals
incidence: <1yr, usually resolves by 3 years
associations: Noonan’s, hypertrophic CM
Myocarditis
pathogenesis: cell mediated immunologic reaction causing myocardial inflammation and necrosis leading to fibrosis/dilation/cardiomyopathy
causes
viral: coxsackie B, adenovirus, CMV, echovirus, EBV, Hep C, herpes, HIV, influenza, measles, mump, rubella, varicella
bacterial: mycoplasma, staph
toxins: cocaine, EtOH, diptheria
immune: rheumatic fever, kawasaki, SLE, thyrotoxicosis, IBD
clinical: fever, chest pain, palpatations, syncope, shock
ECG: low voltage QRS, ST-T changes, PR/QT prolongation, arrythmias
XR: cardiomegally
bloods: troponin, CK, viral serology
prognosis: 75% mortality in neonates
treatment: CHF drugs, IVIg
Non-cardiac syncope
behavioural: breath holding spells
metabolic/endocrine: DM, DI, adrenal insufficiency
neurological: seizures, vertobasilar migraine
psychiatric: conversion
vasovagal: diagnosis of exclusion
Noonan’s
cardiac issues
pulmonary stenosis 65%
- also associated with hypertrophic cardiomyopathy
Pacemaker AP
Patent Ductus Arteriosus
PDA
incidence: 5-10% CHD, F>M
pathogenesis: failure of DA to close in early weeks of life
- large PDA causes increased pulmonary pressure
clinical: tachypnoea, CO2 retention, apnoeas, CHF
examination: bounding pulses, wide PP, palpable thrill
mumur: continuous machine like
ECG: LVH
CXR: increased pulmonary vascular markings, cardiomegally
treatment:
- medical: PGE1 inhibitors, diuretics
- surgical: <2mm coil/plug, >2mm surgical
Pericarditis
pathogenesis: inflammation of parietal and visceral surfaces of the pericardium
causes
- viral: coxsackie, echovirus, mumps, influenza, epstein-barr, CMV
- bacterial: staph aureus, strep pneumo, pneumococcus, meningococcus, HiB, TB
other: fungal, collagen vascular disease, metabolic, neoplasm
CXR: cardiomegally
ECG: tachycardia, elevated ST, reduced QRS
treatment: pericardiocentesis, anti-inflammatory medications
Peripheral pulmonary hypertension
incidence: 1/1500
diagnosis: PA>25mmHg
pathogenesis
pulmonary vasoconstriction: hypoxia
increased pulmonary SM hypertrophy: chronic asphyxia, maternal PGE inhibitors
decreased area vascular bed: diaphragmatic hernia, pulmonary hypoplasia, fibrosis, inflammation
other: excess endothelin, deficit NO/prostacyclin
ECG: normal
CXR: cardiomegally
treatment: reverse cause, 100% oxygen, inhaled NO
Peripheral vascular resistance
PVR: (mean PA pressure-mean LA pressure)/Flow
Persistent Truncus Arteriosus
pathogenesis: single origin of PA and aorta from the heart
- large VSD always present
- blood from both ventricles passes across VSD to single trunk
- lung exposed to high pressure circulation
associations: Di George, maternal DM
treatment: surgery (<6m) closure VSD and conduit to connect RV to PA
Premature atrial contractions
incidence: common in childhood
pathogenesis: premature beat arising from an ectopic focus within the atria
ECG: may have normal, prolonged or absent QRS
- premature p wave may be superimposed on t wave
- p waves usually different axis
- long pause after premature atrial contraction
Premature ventricular contractions
definition: premature, widened bizarre QRS complexes not preceded by p wave
types
- bigeminy: 1 PVC for each QRS
- trigeminy: 1 PVC for 2 normal QRS
pathological: 2 or more PVCs in a row, multiform PVCs, increased PVCs with exercise, R on T phenomenon, underlying heart disease
treatment: none, lidocaine, procainamide
Pulmonary atresia with intact VS
pathogenesis: PA valves fused and triscupid valves are hypoplastic so blood shunts via FO to LA and entire volume flows into LV to the aorta
clinical: cyanosis, respiratory distress
examination: single S2, harsh systolic mumur
ECG: LAD, tall p waves
treatment: PGE1, surgery (pulmonary valvotomy, A-P shunt)
Pulmonary Shunt Fraction
Qp:Qs= (SatA-SatSVC)/(SatPV-SatPA)
Pulmonary stenosis
incidence: 10% CHD
pathogenesis:
- valvular PS: PV thickened with small orifice and hypoplastic RV
- isolated infundibular PS: rare, associated large VSD
- supravalvular PS: 3% CHD, stenosis of single or multiple branches PA, associated PV stenosis/VSD/TOF
associations: rubella, William’s, Noonan’s, Allagille, Ehler-Danlos, Silver-Russell
clinical: SOB, tachypnoea, poor feeding, cyanosis
examination: split S2, ejection click, RV thrill, ESM left 2nd ICS
ECG: RVH
CXR: normal
treatment: PGE1, surgery (balloon valvuloplasty, valvotomy)
Pulsus paradoxus
definition: drop BP>10mmHg during inspiration
pathogenesis: inspiration causes negative thoracic pressure and increased venous return
- increased pulmonary blood capacity decreasing left sided return
Restrictive cardiomyopathy
incidence: rare
causes:
- infiltration: amyloidosis, sarcoidosis
- non-infiltrative: idiopathic, familial
- storage diseases: haemochromatosis, Fabry
- endomyocardial disease
pathogenesis: massive atrial dilatation
clinical: dyspnoea, respiratory illness, syncope, hepatomegally
examination: S4
ECG: atrial enlargement
Right Atrial Hypertrophy
causes:
- tricuspid atresia
- hypoplastic right heart
- ebstein’s anomaly
- pulmonary atresia
Schwartz long QT diagnostic criteria
Sick sinus syndrome
pathogenesis: dysfunction of SA node secondary to dysgenesis of SA node and surround atrial myocardium
incidence: older people
clinical: fatigue, lightheadedness, palpitations
ECG: bradycardia with sinus pauses and sinus arrest
treatment: PACEMAKER
Single S2
cause: loss of A2 or P2
differentials: severe AS/PS, severe AR, absent pulmonary valve, TOF, Ebstein’s anomaly, pericardial effusion
Sinus arrhythmias
phase sinus arrhythmia: impulse discharge related to respiration
- increases with inspiration, decreases with expiration
sinus bradycardia: fitness, anorexia, beta blockers, high vagal tone, sleep, hypothyroidism
extrasystoles: isolated extrasystoles unsignificant
Spontaneous Bacterial Endocarditis
risk factors
- Multiple interventions ie. CVC
- Immunocompromised
- Unrepaired cyanotic heart defect
- Prosthetic material
investigations: 3 blood cultures in 48 hours prior ot AB
prophylaxis: PO amoxycillin 1 hr prior to procedure or IV if with anaesthetic
Sudden cardiac death
CAD (30%): abberant origin left coronary artery, acquired (Kawasaki, atherosclerosis), coronary arteritis
primary arrythmia (22%): WPW, long QT, brugada, torsades, myopathies, pre-excitation syndromes, CHB
cardiomyopathies (20%): dilated, hypertrophic, restrictive, myocarditis, arrythmogenic RV cardiomyopathy
CHD (15%): HLHS, TGA, TOF
other: obstructive lesions, tumours, Marfan’s, pulmonary HTN, sarcoidosis, aortic dissection
SVT
incidence: commonest cause tachycardia in children
pathogenesis: all forms of tachycardia except VT
3 types:
- reenterant tachycardia with accessory p/w
- reenterant tachycardia w/o accessory p/w
- ectopic or automatic tachycardias
diagnosis: HR>220, p waves present and related to QRS
treatment: vagal manouvers, medications (adenosine, digoxin, CCB, beta blockers), cardioversion
Sympatholytics
beta blockers:
- mechanism: decreased renin release, decreased AII and blocks B1
- SE: asthma, bradycardia, AV block, CHF, impotence, sedation
clonidine/methyldopa:
- mechanism: central alpha 2 agonist, decreases NE release
- SE: sedation, dry mouth, rebound HTN
prazosin:
- mechanism: alpha 1 blocker
- SE: orthostatic hypotension
Syncope
-pathological signs-
- associated stress/exercise
- whilst supine
- in water
- palpitation prior
- family hx death before 30yrs
- odd history
Systemic vascular resistance
SVR= (mean aortic pressure-mean RA pressure)/flow
Tet (hyperpcyanotic) spells
incidence: TOF patients 2-4 months
pathogenesis:
- triggered decreased systemic vascular resistance
- increased R to L shunt
- decreased pulmonary blood flow
examination: cyanosis, no mumur, LOC
treatment: knee-chest position to increased venous return, oxygen, morphine, propranolol for prevention
Total Anomylous Pulmonary Venous Return
TAPVR
definition: pulmonary veins return to the venous system with hypoplasia of the left heart causing mixing of systemic and pulmonary blood
- all have ASD or incompatible
pathogenesis: abnormal development pulmonary veins week 3 gestation
types:
- supracardiac 50%
- cardiac (usually RAD) 20%
- infracardiac (portal vein, ductus venosus, hepatic vein, IVC) 20%
- mixed 10%
clinical: poor growth
examination: mild cyanosis, hyperactive RV impulse, S2 widely split, ESM in pulmonary area, mid diastolic mumur TV
ECG: RVH
CXR: cardiomegally ‘snowman’, increased pulmonary markings
management: medications (PGE1), surgery (balloon atrial septostomy, return of PA to LA)
prognosis: 60% dead by 1yr if untreated
Transposition of the Great Arteries
TGA
incidence: 5% CHD but most common cyanotic lesion in newborn period
pathogenesis: aorta arises RV, PA arises left ventricle
- 50% have mixing defect: 40% VSD, 50% PFO/PDA
clinical: early cyanosis
examination: palpable left/right ventricular impulses, loud/single S2, pansystolic mumur (VSD)
ECG: RAD, RVH, Q waves in V1
CXR: egg on string, increased pulmonary vascularity
treatment: PGE1 infusion, surgery (enlarged FO via balloon septostomy, arterial switch operation at week 2)
Tricuspid Atresia
incidence: 1-3% CHD
definition: absent connection between right atrium and ventricle with hypoplastic right ventricle
- blood diverted from RA to LA via ASD/FO
- then from LV to RV
clinical: cyanosis, poor feeding, TET spells
examination: single S2, increased LV impulse, mumur, CHF, clubbing
ECG: LAD, LVH
CXR: cardiomegally, decreased pulmonary markings
treatment: early (PGE1, Blalock-Taussig procedure), late 2yrs (Fontan operation connecting SVC to PA with VSD patch)
prognosis: LVH causes cardiomyopathy
Tricuspid Stenosis
incidence: rare
clinical: mid diastolic mumur, right heart failure
ECG: left axis deviation, RAH, peaked p waves
Trisomy 21
cardiac issues
50% have cardiac anomalies
- AVSD 40%
- AVSD>VSD>ASD>PDA
- TOF
Truncus Arteriosus
incidence: 1% CHD
definition: single arterial trunk from the heart with a large VSD below the truncal valve
pathogenesis: failure of separation of the truncus at 3-4 weeks gestation
clinical: cyanosis, CHF, bounding pulses
examination: systolic ejection click and mumur, single S2
treatment: surgery (VSD closure, conduit between arteries)
Turner’s Cardiac
left heart lesions
- aortic stenosis 10%
- biscuspid aortic valves
- coarctations
- dilated aortic arch
Vascular Ring
incidence: 1-3% all CHD
definition: congenital anomaly of aortic arch with abnormal formation of aorta/surrounding vessels
- complete encircling of the trachea and oesophagus
- incomplete: PA sling (trache + eso), innominate artery compression (trache), abberant right subclavian artery (eso)
associations: VSD, TOF, coarctation, PDA, cleft palate, CHARGE, subglottic stenosis
clinical: stridor, wheeze, dysphagia, feeding issues
diagnosis: CXR, barium swallow, bronchoscopy, MRI/CT
Vasoactive Factors
endothelin-1: released endothelium
- endothelin A: vasocontriction
- endothelin B: stimulates NO release
prostacyclin (PG12)
- released endothelium from COW p/w causing vasodilation
PGH2
- precursor prostcyclin, thromboxane, PGEs
thromboxane A2
- released platelets and causes vasocontriction and platelet aggregation
Velocardial facial syndrome
-cardiac issues-
right sided cardiac issues
- truncus arteriosus, TOF, pulmonary atresia
Ventricular Fibrillation
definition: uncoordinated contraction ventriles
cause: underlying cardiac disease/damage
clinical: significantly decreased CO
ECG: non-distinct QRS/T waves, irregular undulations
treatment: cardioversion
Ventricular Septal Defect
VSD
incidence: 15% CHD
types:
- perimembranous 70%: membranous septum under aortic arch
- outlet 7%: rim formed by aortic/pulmonary annulus
- inlet 8%: AV canal
- trabecular 10%: muscular
clinical: pulmonary HTN, CHF
examination: systolic mumur, systolic thrill, loud P2, enlarged left heart, increased pulmonary flow
ECG: LVH
treatment: 1/3 close spontaneously, surgery if Qp:Qs 2:1, pulmonary HTN
prognosis: RBBB 10%, CHB 2%
Ventricular Tachycardia
definition: >3 premature ventricular beats sustained for >30 secs with HR 120-240
pathogenesis: AV dissociation
clinical: impaired CO
treatment: lidocaine, amiodarone, procainamide, propranolol, cardioversion
William’s Cardiac
supravalvular AS
PA stenosis
Wolf-Parkinson White Syndrome
incidence: 1/1000
pathogenesis: pre-excitation via accessory pathway (Bundle of Kent) formed during cardiac development
- can conduct retrograde/antegrade or both
clinical: SVT
ECG: delta wave, long QRS, ST/T wave changes
treatment: flecainide, procainamide, radioablation
AVOID: AV nodal blockers (adenosine, diltiazem, verapamil, beta blockers, amiodarone)
LEFT TO RIGHT SHUNT
causes:
- VSD (LAH/LVH)
- ASD (RAH/RVH)
- PDA (LAH/LVH)
- PAPVD (partial anomalous pulmonary venous return) (RAH/RVH/PAH)
LEFT CARDIAC OBSTRUCTIVE LESIONS
1. coarctation
2. aortic stenosis (supra/valvular/subvalvular)
3. LV restriction
4. mitral stenosis (supra/valvular/subvalvular)
5. Cor triatriatum
6. PV stenosis
Scimitar syndrome
definition: pulmonary hypoplasia and PAPVR on right side
CXR: small lung with inspilateral mediastinal shift and tubular structure on right heart border
Long QT
Long QT
Fontan procedure
procedure: right atrum connected to the pulmonary artery directly
- pulmonary resistance must be low
prognosis: associated atrial flutter in 50% by 18yrs
