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Assessing C ardiac Function. Gusztav Belteki Rosie Hospital, Cambridge 20/10/2014. Summary of the talk. Transitional circulation Ventricular function Cardiac output. Transitional circulation. Fetal circulation: - Right ventricular dominance - Fetal shunts
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Assessing Cardiac Function Gusztav Belteki Rosie Hospital, Cambridge 20/10/2014
Summary of the talk • Transitional circulation • Ventricular function • Cardiac output
Transitional circulation • Fetal circulation:- Right ventricular dominance- Fetal shunts • Postnatal circulation:- Left ventricular dominance- No shunts (“serially connected” circulation)
Transitional circulation Tricuspid regurgitation Open ductusarteriosus These are normal findings in the first 72 hours and DO NOT mean PPHN or CHD in a newborn who is not hypoxic !
Ventricular function Cardiac output = Heart rate X Stroke volume • Stroke volume is determined by: • - Preload • Contractility • Afterload
Left ventricular contractility • A 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 1 2 2 1
Fractional shortening LVEDD - LVESD X 100 25 – 41 % FS = LVEDD Dependent on contractility AND preload
Ejection fraction (EF) LVEDD3 – LVESD3 (1.2)3 = 1.728 X 100 FS = LVEDD3 • Velocity of circumferential fiber shortening LVEDD – LVESD LVET X Vcfc= sqrtRR LVEDD LVET = left ventricular ejection time
Right ventricular dominance S D S D • Dilated right ventricle • Paradoxical septal motion
Diastolic ventricular function • Hypertrophic cardiomyopathy: • - Infants of diabetic mothers • - Postnatal steroid course • - Inborn errors of metabolism • Immature myocardium (prematurity)
Diastolic ventricular function Normal: E / A > 1 Abnormal: E / A < 0.7 E wave: passive filling A wave: atrial contraction
Cardiac output Mean arterial pressure Cardiac output = Vascular resistance
Cardiac output • No 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. outputPulmonary CO = Right ventr. output
How 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 π) / 4 (cm2)
How to measure left ventricular output Left ventricular output (LVO) = AoSD (cm) x AoCSA(cm2) x HR (bpm) (ml / min / bwkg) Body weight 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 output Right ventricular output (RVO) = PSD (cm) x PCSA (cm2) x HR (bpm) Body weight