TY - JOUR

T1 - Effects of exercise and respiration on blood flow in total cavopulmonary connection

T2 - a real-time magnetic resonance flow study

AU - Hjortdal, V E

AU - Emmertsen, K

AU - Stenbøg, E

AU - Fründ, T

AU - Schmidt, M Rahbek

AU - Kromann, O

AU - Sørensen, K

AU - Pedersen, E M

PY - 2003/9/9

Y1 - 2003/9/9

N2 - BACKGROUND: Little is known about blood flow and its relationship to respiration during exercise in patients with total cavopulmonary connection (TCPC).METHODS AND RESULTS: We studied 11 patients 12.4+/-4.6 years (mean+/-SD) of age 5.9+/-2.8 years (mean+/-SD) after TCPC operation. Real-time MRI was used to measure blood flow in the superior vena cava (SVC), inferior vena cava (IVC), and ascending aorta under inspiration and expiration during supine lower-limb exercise (rest, 0.5 and 1.0 W/kg) on an ergometer bicycle. IVC and aortic flow increased from 1.60+/-0.52 and 2.99+/-0.83 L/min per m2 at rest to 2.58+/-0.71 and 3.97+/-1.20 L/min per m2 at 0.5 W/kg and to 3.25+/-1.23 and 4.62+/-1.49 L/min per m2 at 1.0 W/kg (P< or =0.05). SVC flow remained unchanged. Resting flow in the IVC was greater during inspiration (2.99+/-1.25 L/min per m2) than during expiration (0.83+/-0.44 L/min per m2) (inspiratory/mean flow ratio, 1.9+/-0.5), and retrograde flow was present during expiration (11+/-12% of mean flow). The predominance of inspiratory flow in IVC diminished with exercise to an inspiratory/mean flow ratio of 1.5+/-0.2 (P< or =0.05) and 1.4+/-0.3 at 0.5 and 1.0 W/kg, respectively.CONCLUSIONS: In the TCPC, circulation IVC and aortic but not SVC flows increase with supine leg exercise. Inspiration facilitates IVC flow at rest but less so during exercise, when the peripheral pump seems to be more important.

AB - BACKGROUND: Little is known about blood flow and its relationship to respiration during exercise in patients with total cavopulmonary connection (TCPC).METHODS AND RESULTS: We studied 11 patients 12.4+/-4.6 years (mean+/-SD) of age 5.9+/-2.8 years (mean+/-SD) after TCPC operation. Real-time MRI was used to measure blood flow in the superior vena cava (SVC), inferior vena cava (IVC), and ascending aorta under inspiration and expiration during supine lower-limb exercise (rest, 0.5 and 1.0 W/kg) on an ergometer bicycle. IVC and aortic flow increased from 1.60+/-0.52 and 2.99+/-0.83 L/min per m2 at rest to 2.58+/-0.71 and 3.97+/-1.20 L/min per m2 at 0.5 W/kg and to 3.25+/-1.23 and 4.62+/-1.49 L/min per m2 at 1.0 W/kg (P< or =0.05). SVC flow remained unchanged. Resting flow in the IVC was greater during inspiration (2.99+/-1.25 L/min per m2) than during expiration (0.83+/-0.44 L/min per m2) (inspiratory/mean flow ratio, 1.9+/-0.5), and retrograde flow was present during expiration (11+/-12% of mean flow). The predominance of inspiratory flow in IVC diminished with exercise to an inspiratory/mean flow ratio of 1.5+/-0.2 (P< or =0.05) and 1.4+/-0.3 at 0.5 and 1.0 W/kg, respectively.CONCLUSIONS: In the TCPC, circulation IVC and aortic but not SVC flows increase with supine leg exercise. Inspiration facilitates IVC flow at rest but less so during exercise, when the peripheral pump seems to be more important.

KW - Aorta/physiology

KW - Blood Flow Velocity

KW - Child

KW - Echocardiography

KW - Electrocardiography

KW - Exercise/physiology

KW - Exercise Test

KW - Female

KW - Fontan Procedure

KW - Heart Bypass, Right

KW - Heart Defects, Congenital/physiopathology

KW - Heart Rate

KW - Humans

KW - Magnetic Resonance Imaging

KW - Male

KW - Respiration

KW - Rest/physiology

KW - Stroke Volume

KW - Vena Cava, Inferior/physiology

KW - Vena Cava, Superior/physiology

U2 - 10.1161/01.CIR.0000087406.27922.6B

DO - 10.1161/01.CIR.0000087406.27922.6B

M3 - Journal article

C2 - 12939218

VL - 108

SP - 1227

EP - 1231

JO - Circulation

JF - Circulation

SN - 0009-7322

IS - 10

ER -