Cardiology Flashcards
At what concentration of deoxyhemoglobin can cyanosis be detected clinically?
> 5g/dL
When does the ductus arteriosus close in a term infant?
- Functional closure within the first 15 hours of life
- Anatomic closure within the first few days of life
» Usually around 48 hours of life
What is the definition of heart failure?
Inadequate cardiac output to meet the metabolic needs of the body
How can we classify congenital heart disease?
Cyanotic VS. Acyanotic
Acyanotic - L>>R Shunts >> ASD >> PSD >> PDA >> AVSD/Endocardial cushion defect - Obstruction >> Coarctation of the aorta >> Pulmonary stenosis >> Aortic stenosis
Cyanotic - R>>L Shunts >> Tetralogy of Fallot >> Ebstein's anomaly - Others >> Truncus arteriosus >> Transposition of the great vessels >> Tricuspid atresia >> Pulmonary atresia >> Total anomalous pulmonary venous drainage >> Hypoplastic left heart syndrome
What conduction defect is Ebstein’s anomaly associated with?
Wolff-Parkinson-White disease
What is the most common cause of CHD death in the first month of life?
Hypoplastic left heart syndrome
What is shunt volume dependent upon?
- Size of the defect
- Pressure gradient between the two connected chambers or vessels
- Peripheral outflow resistance
What are the complications of acyanotic congenital heart disease, mainly the left-to-right shunts?
- Eisenmenger syndrome (pulmonary hypertension»_space; right-to-left shunt)
- Congestive heart failure
What are the three types of atrial septal defect?
- Ostium primum (endocardial cushion defect)
- Ostium secundum
- Sinus venosus
What is the most common type of atrial septal defect?
Ostium secundum
- Enlarged foramen ovale
- Inadequate growth of the septum secundum
- Excessive absorption of septum primum
What is the natural clinical course of ASD?
- Congenital heart disease
- 80-100% spontaneous closure if ASD diameter > Congestive heart failure
»_space; Pulmonary hypertension
Name 3 diagnostic studies for ASD.
- ECG: right axis deviation, mild RVH, RBBB
- Echocardiogram
- Cardiac catheterization
What is the treatment for ASD?
- Conservative: 80-100% spontaneous closure if <8mm
- Treat heart failure
- Diuretics: frusemide, spironolactone
- Vasodilators: captopril, hydralazine
- Digoxin
- Surgical/catheter closure – elective at 2-5 years
What are the complications of ASD closure?
- Arrhythmias
- Pericardial effusion
What is the most common congenital heart defect?
Ventricular septal defect (30-50%)
What is the management for VSDs?
Dependent on the size of VSD
- Conservative
- Most small VSDs close spontaneously
- Treat heart failure
- Diuretics
- Vasodilators: captopril, hydralazine
- Digoxin
- Surgical closure by 1 year of age
What is the likelihood of developing congestive heart failure in a VSD?
By 2 months in moderate-to-large VSD
|»_space; Late secondary pulmonary hypertension if left untreated
What are the presenting features of CHF in a child?
- Poor feeding
- Delayed growth
- Decreased exercise tolerance
- Recurrent URTIs/asthma episodes
- Tachycardia
- Tachypnoea
- Hepatomegaly
- Cardiomegaly
> > Look for murmurs upon auscultation for congenital heart diseases
What are the four types of VSDs?
- Muscular
- Perimembranous
- Supracristal
- Inlet (related to AVSD)
What are the complications of surgical repair of VSD?
- Residual VSD
- Aortic insufficiency
- Complete heart block
What are the physical findings of a patent ductus arteriosus?
- Tachycardia
- Bounding pulse
- Widened pulse pressure
- Hyperactive precordium
- Continuous machinery murmur best heard over the left infraclavicular region
What are the possible causes of a hyperactive precordium?
- Tachycardia
- Ventricular hypertrophy
- Aortic coarctation
- Patent ductus arteriosus
- Hyperthyroidism
What is the natural clinical course of PDA?
- Delayed closure of ductus is common in premature infants (1/3rd in infants > If a PDA persists beyond the first week of life, it is unlikely to close spontaneously
What are the presenting features of a PDA?
- Asymptomatic
- Poor feeding
- Apneic or bradycardic spells
- Use of accessory muscles for breathing
What is the management of PDA?
- Conservative: spontaneous closure is common in premature infants
- Medical: indomethacin/ibuprofen for premature infants
- Surgical/catheter closure
What are the indications for surgical/catheter closure of PDA?
- Respiratory distress
- Failure to thrive
- Persistence beyond 3 months of age
What are the complications of PDA repair?
Residual shunt
What are the presenting features of obstructive heart lesions?
- Decreased urine output
- Pallor
- Cold extremities
- Weak pulses
- Shock or sudden collapse
What are the common ductal-dependent heart lesions?
Pulmonary flow
- Critical pulmonary stenosis
- Pulmonary atresia
- Tricuspid atresia
- Tetralogy of Fallot
- Transposition of great vessels
- Truncus arteriosus
- Total anomalous pulmonary venous return
Systemic flow
- Coarctation of the aorta
- Hypoplastic left heart syndrome
When does congestive heart failure typically present?
At birth
- Large volume overload lesions
»_space; Tricuspid regurgitation
»_space; Pulmonary regurgitation
First week of life
- Ductal dependent lesions
- The ductus usually closes within the first 15 hours functionally and anatomically closes within the first week of life
First-Second months of life - Significant left-to-right shunts >> ASD >> VSD >> AVSD >> PDA - When increased pulmonary vascular resistance starts to develop
What is coarctation of aorta?
Narrowing of the aorta, almost always at the level/slightly distal to the ductus arteriosus
What are the CXR findings of coarctation of aorta?
- Dilated ascending aorta
- Coarctation segment
- Dilated descending aorta
- Rib notching from dilated intercostal vessels in older children
What are the presenting features of coarctation of aorta?
- Upper extremity systolic pressures elevated
- Decreased blood pressure in lower extremities
- Weak/absent pulses in the lower extremities
- Radial-femoral delay in older children
- Shock in the neonatal period when the ductus closes if obstruction is severe
What is the management of coarctation of aorta?
- Keep ductus patent with prostaglandins
- Surgical correction in neonates: extended end-to-end antastomosis via thoracotomy
- Catheterization in older children
»_space; Balloon angioplasty
»_space; Stent placement
What are the 4 types of aortic stenosis?
- Valvular
- Subvalvular
- Supravalvular
- Idiopathic hypertrophic subalrtic stenosis (IHSS) = HOCM
What is the management of aortic stenosis?
Depends on the type of AS
- Valvular: balloon valvuloplasty
- Subvalvular/Supravalvular: surgical repair, exercise restriction required (esp. for HOCM)
What are the 3 types of pulmonary stenosis?
- Supravalvular
- Valvular
- Subvalvular
What is the definition of critical pulmonary stenosis?
- Inadequate pulmonary blood flow
- Ductus-dependent
- Progessive hypoxia and cyanosis
What is the management for pulmonary stenosis?
- Conservative
- Surgical
- Critically ill
- Symptomatic older children
What are the four features defining the Tetralogy of Fallot?
- Pulmonary stenosis
- Right ventricular hypertrophy
- Ventricular septal defect
- Overriding aorta
What are “tet spells”?
Increased pulmonary vascular resistance with decreased systemic vascular resistance during exertional stage increases the right-to-left shunt of TOF
- Rapid deep breathing
- Irritability
- Increasing cyanosis
- Decreased intensity of the murmur
> > If severe: seizures and death
What are the characteristic CXR finding of the Tetralogy of Fallot?
Boot-shaped heart
What are the common causes of a right aortic arch?
- Tetralogy of Fallot + pulmonary atresia
- Classical Tetralogy of Fallot
- Truncus arteriosus
- Double outlet right ventricle
- Single ventricle
What is the management of a “tet spell”?
- Knee-chest position
- Oxygen supplement
- Fluid bolus
- Morphine
- Propanolol
What is the management of Tetralogy of Fallot?
- Blalock-Taussig repair/shunt: palliative OT
- Surgical repair at 4-6 months of age
What is the management of congestive heart failure in children?
- Sit up
- Oxygen supplement
- Diuretics
- Vasodilators: captopril, hydralazine
- Digoxin
> > Surgical repair of underlying problem
What is the most common cyanotic congenital heart disease in a neonate? What are the associated presenting features
Transposition of the Great Arteries (TGA)
» Big blue baby
» Ductus arteriosus closure within the first week causes rapidly progressive hypoxemia that is UNRESPONSIVE TO OXYGEN THERAPY
What is the classical CXR finding for transposition of the great arteries?
Egg-on-a-string
What is the management for transposition of the great arteries?
- Keep ductus open by PGE1 infusion + balloon atrial septostomy
- Surgical repair within the first 2 weeks of life in those without an ASD
What is the management for total anomalous pulmonary venous circulation/return?
Surgical repair in ALL cases
- Urgently for severe cyanosis
What lesion must be present in a child with tricuspid atresia?
Atrial septal defect
What is the management for truncus arteriosus?
Surgical repair within the first 6 weeks of life
What are the features of hypoplastic left heart syndrome? Name 4.
- Hypoplastic left ventricle
- Narrow mitral/aortic valves
- Small ascending aorta
- Contracted aorta
> > Culminates to systemic hypoperfusion
DUCTAL-DEPENDENT SYSTEMIC CIRCULATION
What is the management for hypoplastic left heart syndrome?
- Supportive treatment
» Resuscitate
» Intubate
» Correct metabolic acidosis/ electrolyte anomalies - IV infusion of PGE1 to keep ductus open
- Surgical
»_space; Palliative OT
»_space; Heart transplant
What are the features of congestive heart failure in children?
Infants
- Poor feeding with failure to thrive
- Early fatigability
- Lethargy
- Signs of respiratory distress
Children
- Decreased exercise tolerance
- Fatigue
- Decreased appetite
- Failure to thrive
- Signs of respiratory distress
- Recurrent URTIs/asthma episodes
What are the four cardinal features of congestive heart failure in children?
- Tachycardia
- Tachypnea
- Cardiomegaly
- Hepatomegaly
+ Failure to thrive
What are the causes of congestive heart failure in children?
Congenital
- Congenital heart diseases
- Arteriovenous malformation
- Congenital arrhythmias
- Congenital cardiomyopathies
Acquired
- Myocarditis
- Cardiomyopathy
- Arrhythmias
- Acute hypertension
- Cor pulmonale
- Anemia
What are some ECG changes for hyperkalemia?
- Tented T-wave
- Increased PR interval
- Widened QRS
- Absent P-wave
- Sinusoidal wave in late cases
What are some ECG changes for hypokalemia?
- Decrease ST segment
- Diphasic T-wave
- Decreased PR interval
- Shortened QRS
- U-wave
What are some ECG changes for hypocalcemia?
Prolonged QT interval
What are some ECG changes for hypercalcemia?
Shortened QT interval
What are the most common mechanisms for supraventricular tachycardia in children?
AV re-entry lesions
- Wolff-Parksinson-White syndrome (Ebstein’s anomaly)
- HOCM/Dilated myopathy
- Hyperthyroidism
AV nodal re-entry lesions
What is the most frequent sustained dysarrhythmia in children?
Supraventricular tachycardia
What is the management for SVT?
1. Conservative maneuvres
>> Ice bag on forehead
>> Valsalva maneuvre
>> Carotid massage
2. Electrocardioversion
3. Pharmacotherapy
>> Adenosine
>> Verapamil - rarely usedWhat is a benign premature ventricular complex?
- Single
- Uniform
- Disappears with exercise
- No structural lesions
What are the common causes of congenital heart block?
Maternal anti-Ro or anti-La antibodies (SLE)
- Often diagnosed in utero
- May lead to fetal hydrops
What are the characteristics of an innocent murmur?
- Systolic
- Soft and musical in nature
- Equal or less than grade 2/6
- Best heard over the left lower sternal border
What is the most common complication of PDA in childhood?
Infective endocarditis
What are the criteria for diagnosing infective endocarditis?
Modified Duke's criteria 1. Major criteria - Positive blood culture of atypical IE microorganism >> Viridans >> Strep bovis >> Staph aureus >> HACEK group - Evidence of endocardial involvement on ECHO
- Minor criteria
- Any predisposing factors: known cardiac lesions
- Fever >38C
- New murmur
- Any embolic phenomenon
» Osler nodes
» Janeway lesions
» Finger splinter hemorrhages
» Roth spots on the retina
» Pulmonary infarcts
- Immunological problems
» Glomerulonephritis
» Rheumatoid factor
> > 1 major + 1 minor
3 minors
What is the diagnostic criteria for rheumatic fever?
JONES's criteria J: Joints (polyarthritis) O: Heart murmurs N: Subcutaneous nodules E: Erythema marginatum S: Sydenham's chorea
Minor criteria:
Fever 38.2-38.9C
- Raised ESR/CRP
- Leukocytosis
- ECG: features of a heart block (e.g. prolonged PR)
- Previous episodes of rheumatic fever or inactive heart disease
> > 2 major
1 major + 2 minor
What is the most appropriate specific treatment for rheumatic fever?
Benzathine benzylpenicillin
|»_space; Look out for congestive heart failure
