Pressure-volume loop-derived cardiac indices during dobutamine stress: a step towards understanding limitations in cardiac output in children with hypoplastic left heart syndrome.
Int J Cardiol
; 230: 439-446, 2017 Mar 01.
Article
en En
| MEDLINE
| ID: mdl-28043677
ABSTRACT
BACKGROUND:
Children with a single systemic right ventricle, such as in hypoplastic left heart syndrome (HLHS), frequently experience reduced exercise capacity. Elucidating the causes could help with optimising treatment strategies.METHODS:
Prospective data from 10 consecutive symptomatic patients with HLHS undergoing clinical cardiac magnetic resonance with catheterisation (XMR) were analysed. Mean age 8.6years (range 3.5-11.6years), mean time since Fontan completion 5.5years. MR-compatible catheters were placed in the systemic right ventricle and branch pulmonary arteries to record pressures at rest, with dobutamine infusion at 10mcg/kg/min and at 20mcg/kg/min. Cine short-axis stacks of the ventricle were performed at each condition and used to construct pressure-volume loops.RESULTS:
Compared to rest, cardiac index increased with low-dose dobutamine (p<0.01) with no further rise at peak stress despite a further, albeit, blunted rise in heart rate (p=0.002). A fall in stroke volume occurred (p=0.014) despite good contractility (74% increase, p=0.045) and a well-coupled ventriculo-arterial ratio. End-diastolic pressure and early active relaxation, markers of diastolic function, were normal at rest. However, preload fell at peak stress (p<0.008) while pulmonary vascular resistance (PVR) was low throughout. This group of HLHS patients demonstrated a fall in SV at peak stress, coinciding with a fall in preload.CONCLUSIONS:
Markers of systolic and diastolic function remained normal. Failure to adequately fill the ventricle implies a ceiling of maximal flow through the Fontan circuit despite low PVR.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Gasto Cardíaco
/
Tolerancia al Ejercicio
/
Síndrome del Corazón Izquierdo Hipoplásico
Tipo de estudio:
Prognostic_studies
Límite:
Child
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Child, preschool
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Female
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Humans
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Male
Idioma:
En
Revista:
Int J Cardiol
Año:
2017
Tipo del documento:
Article
País de afiliación:
Reino Unido