Cardiology Flashcards
(109 cards)
Most common cause of dilated cardiomyopathy
50% Idiopathic
46% myocarditis (adeno, entero, HHV6/coxsackie, CMV)
35% genetic (mainly neuromuscular disease)
Most common cause of HOCM
30-60% inherited- AD mutations in sarcomeric proteins
- Troponin T mutations: beta-myosin heavy chain MYH7 and myosin binding protein C MYBPC3
- 50% spontaneous
HOCM associated syndromes
Noonan, BWS, LEOPARD, Friedrich Ataxia
Echo findings in obstructive HOCM
HOCM - systolic anterior motion (SAM) of the mitral valve against the hypertrophied septum
Treatment of HOCM
Exercise restriction, B-blockers, myotomy, antiarryhmics, ICD if high risk
Features of restrictive cardiomyopathy, prognosis?
Diastolic dysfunction with normal LV thickness
- Biatrial enlargement on Echo
- Poor prognosis, progressively worsens
- Rare 5% of childhood CM
- DDx constrictive pericarditis
Features of arrythmogenic RV cardiomyopathy
RV myocardium replaced by fatty/fibrous tissue, systolic bulging of RV wall
Pathophys of CCF- compensatory mechanisms heart/kidney
Decreased SV + CO
- Ventricular dilatation/hypertrophy
- Increased EDP/impaired filling (eventually SV cannot increase and plateaus)
- Increased SNS activation- HR & contractility ^ - damages myocardium chronically
- Dec RBF = inc RAAS (Ang 2 = inc Na/H20 reabs/vasoconstriction- promotes myocardial fibrosis)
DDx 12wk baby presenting with failure
VSD, ALCAPA
Rejection prevention in heart transplant?
Triple therapy: CNI (tacro/evero/sirolimus) + cyclosporin/antimetabolite/WBC enzyme inhibitor (AZA/MMF/6MP) + prednisolone
Most common cause of post transplant infection
CMV 25%
- consider IV gancyclovir prophylaxis if donor CMV +ve
Difference in pathophys acute cellular vs humoral vs chronic transplant rejection
- Acute cellular: T cell mediated, may have antibodies (ATGAM, OKT3)
- Acute humoral: alloantibodies to HLA/endothelial antigens (complement staining on Bx)
- Chronic: diffuse immune mediated, cause unknown
PHTN: common vasodilators
- NO (endothelial release) - increases cGMP, diffuses into smooth musc to vasodilate, PDE breaksdown, PDE inhibitors (i.e sildenafil) ^ vasodilation
- Arachadonic acid pathway- prostaglandin I2/prostacyclin
- Adenosine
- Oxygen
PHTN: vasoconstrictors
- Hypoxia potent vasoconstrictor (pulm oedema, PE, lung compression)
- ET-1
- Thromboxane A2
- Vasoconstriction from SNS overactivity
Features of Eisenmengers
Shunt reversal R-L in acyanotic lesion - VSD classical, also ASD, AVSD/ECD, PDA
- Influenced by pulm pressure, PBF & hypoxia
- Grade 1-5 based on severity of small arteriolar obstruction
- Usually 2nd/3rd decade, T21 earlier
- Resistant to medical Mx
Risk factors/causes of PPHN
MAS 41%, pneumonia/RDS 15%, CDH 10%, pulm hypoplasia 5%, idiopathic 20%
Causes of PPHN
- Vasoconstriction with normal vasculature
- Alveolar hypoxia- MAS, HMD, CNS hypoventilation
- Birth asphyxia, shock
- Infections
- Polycythemia - Arteriolar hypertrophy
-Intrauterine asphyxia
- Maternal meds - Developmentally abnormal vasculature
- CDH, pulm hypoplasia
Most common infective endocarditis organisms
Prev >90% strep viridians, staph aureus & enterococci
Rise of HACEK
- Haemophilus
- Actinobacillus
- Cardiobacterium
- Eikinella
- Kingella
S.Viridians most common after dental surgery
Staph most common post op
Enterococcus most common post GI/GU surgery
Indications for IE prophylaxis
- Prev IE
- Prosthetic heart valves
- Unrepaired cyanotic CHD, CHD with prosthetic device/residual defect
- Heart transplant patients
- ?ASD/repaired ASD/PDA
Pre-op (dental, mouth/skin/MSK)
high risk- as above
Not indicated in low risk- acquired valve disease, pacemakers, repaired acyanotic CHD
Indications for IE prophylaxis
- Prev IE
- Prosthetic heart valves
- Unrepaired cyanotic CHD, CHD with prosthetic device/residual defect
- Heart transplant patients
Pre-op (dental, mouth/skin/MSK)
high risk- as above
Not indicated in low risk- ASD
Most common cause of myocarditis, mortality risk assoc.
Viral- adeno, entero, echino
Up to 75% mortality
Rx bed rest, high dose IVIG, CCF meds (diuretics, inotropes), ACEi/antiarrythmics
Most common cause of myocarditis, mortality risk assoc.
Most common cause of pericarditis by age group
Infant/young children: viral
Older children: ARF, bacterial (S.Aureus, H.Influenza, N.Meningitidis)
Mx of constrictive pericarditis and outcomes
Pericardial resection - improvement in 75% of patients