#congenital-heart - most common cause of congenital shunt - X-ray "boot shaped" heart - **issues** - RV outflow obstruction - VSD # features - "tet spells" - hypercyanosis, exertional dysponea, haemoptysis, seizures, syncope precipitated by crying or feeding → results in ==increased right to left shunting== - bring their knees in to chest → reduces systemic venous return → increase systemic vascular resistance → reduce right-to-left shunting ![[Pasted image 20230822234054.png]] > 1. pulmonary stenosis → narrowing of RV outflow > 2. VSD (starts left to right, becomes right to left) > 3. Right ventricular hypertrophy > 4. overriding aorta (blood from both ventricles can enter systemic circulation) # clinical exam findings - cyanosis - normal peripheral pulses - may have AF on holter - clubbing - signs of polycythaemia - [[heart murmurs|aortic ejection click]] due to a dilated, overriding aorta - systolic murmurs # Manage cyanotic episodes ![[Pasted image 20231206134250.png]] metaraminol 10mcg/kg (eg 0.01mg/kg); dilute 2mL (1mg) from 3mg/6mL vial up to 10 mL - calm, oxygen, morphine 0.1mg/kg IV/IM or fent 1.5 mcg/kg IN - increase preload with fluid bolus 10-20mL/kg - increase systemic vascular resistance : knee-to-chest or squatting, metaraminol **Tet spell cause** - acute episode of cyanosis or exaggerated cyanosis compared to baseline, usually w. TOF or pulm atresia - most commonly occur btwn 2-6 months of age - usually occur during times of stress, eg unwell with infection, upset or upon walking - most episodes are self-limiting features: - hyperpnoea - uncontrolled crying - worsening cyanosis - limpness *mechanism:* acute decrease in SVR eg crying → ↑ right-to-left shunting of deoxygenated blood across VSD → ↓ arterial PaO2 and increased CO2, ↓ pH → stimulation of hyperpnea (deep and rapid breathing) → ↑ negative intrathoracic pressure with an resultant ↑ of systemic venous return to right heart