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Assessing Cardiac FunctionGusztav BeltekiRosie Hospital, Cambridge20/10/20141Summary of the talkTransitional circulationVentricular functionCardiac outputTransitional circulationFetal circulation:- Right ventricular dominance- Fetal shunts

Postnatal circulation:- Left ventricular dominance- No shunts (serially connected circulation)

Transitional circulation

Tricuspid regurgitation

Open ductus arteriosusThese are normal findings in the first 72 hours and DO NOT mean PPHN or CHD in a newborn who is not hypoxic !Ventricular functionStroke volume is determined by:

- PreloadContractilityAfterload

Cardiac output = Heart rate X Stroke volume Ventricular functionLeft ventricularRight ventricularSystolic = ContractilityDiastolicLeft ventricular contractilityA useful method of assessing ventricular contractility is visual inspection of the apical four chamber view by a trained eye

Quantitative methods: - fractional shortening (FS)- ejection fraction (EF)- velocity of circumferential shortening (Vcf)M-mode of the left ventricle

1212Fractional shorteningFS = LVEDD - LVESD LVEDDX 10025 41 %Dependent on contractility AND preload

Poor contractility

FS = LVEDD3 LVESD3 LVEDD3X 100Ejection fraction (EF)(1.2)3 = 1.728 Velocity of circumferential fiber shorteningVcfc = LVEDD LVESD LVEDDXLVET = left ventricular ejection timeLVETsqrtRR

Right ventricular dominance

SDDSDilated right ventricleParadoxical septal motion

Right ventricular contractilityDiastolic ventricular functionHypertrophic cardiomyopathy:- Infants of diabetic mothers- Postnatal steroid course- Inborn errors of metabolism

Immature myocardium (prematurity)Hypertrophic obtructive cardiomyopathy

Diastolic ventricular function

Normal: E / A > 1Abnormal: E / A < 0.7

E wave: passive fillingA wave: atrial contractionCardiac outputCardiac output = Mean arterial pressure Vascular resistanceCardiac outputNo shunts: systemic and pulmonary circulations serially connected: Systemic CO = Pulmonary CO

Shunts (ASD, VSD, PDA): Systemic CO = Pulm. CO

VSD, PDA: Systemic CO = Left ventr. output Pulmonary CO = Right ventr. outputHow to measure left ventricular output

Aortic stroke distance = aortic root velocity-time integral (VTI)

AoSD normal (term newborn) 15 3 cm How to measure left ventricular output

Aortic root diameter (d)

Aortic root cross sectional area (AoCSA)

AoCSA = (d2 x ) / 4 (cm2)

How to measure left ventricular outputLeft ventricular output (LVO) =

AoSD (cm) x AoCSA (cm2) x HR (bpm)Body weight(ml / min / bwkg)Normal (term newborn): 160 320 mL/kg/min

BUT: in case of PDA or VSD left ventricular output is not the same as systemic cardiac output !!)Right ventricular outputRight ventricular output (RVO) =

PSD (cm) x PCSA (cm2) x HR (bpm)Body weight