Download Assessment of Cardiac Function

Assessing Cardiac Function
Gusztav Belteki
Rosie Hospital, Cambridge
20/10/2014
Summary of the talk
1. Transitional circulation
2. Ventricular function
3. 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 ductus arteriosus
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
Ventricular function
Left ventricular Right ventricular
Systolic =
Contractility
Diastolic
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
FS =
X 100
25 – 41 %
LVEDD
Dependent on contractility AND preload
Poor contractility
• Ejection fraction (EF)
LVEDD3 – LVESD3
FS =
LVEDD3
X 100
(1.2)3 = 1.728
• Velocity of circumferential fiber shortening
LVEDD – LVESD
LVET
X
Vcfc =
sqrtRR
LVEDD
LVET = left ventricular ejection time
Right ventricular dominance
S
D
- Dilated right ventricle
- Paradoxical septal motion
S
D
Right ventricular contractility
Diastolic ventricular function
• Hypertrophic cardiomyopathy:
- Infants of diabetic mothers
- Postnatal steroid course
- Inborn errors of metabolism
• Immature myocardium (prematurity)
Hypertrophic obtructive cardiomyopathy
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. output
Pulmonary 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)
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 output
Right ventricular output (RVO) =
PSD (cm) x PCSA (cm2) x HR (bpm)
Body weight