Cardiac output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects, elite athletes and patients with congestive heart failure
Cardiac Magnetic Resonance (CMR) enables non-invasive quantification of cardiac output (CO), but reference values for CO and values indexed to body surface area (cardiac index, CI) are lacking. Therefore, the aim was to establish reference values for CI, compare the values to CI in athletes as well as for patients with congestive heart failure (CHF) and to establish if CI decreases with age.MethodS: CI was measured in 144 healthy volunteers (30+/-16 years, range 21-81 years, 68 females), in 60 athletes (29+/-6 years, 30 females) and in 157 CHF patients with ejection fraction (EF) below 40% (60+/-13 years, 31 females).
CI was calculated using aortic flow by velocity-encoded MRI and is presented as mean+/-SD. Flow was validated in vitro using a flow phantom and in 25 subjects with aorta and pulmonary flow measurements.
: There was a slight decrease of CI with age in healthy subjects (8 ml/min/m2 per year, r2=0.07, p<0.01).
CI in males (3.2+/-0.5 l/min/m2) and females (3.1+/-0.4 l/min/m2) did not differ (p=0.24). The mean+/-SD of CI in healthy subjects in the age range of 20-29 was 3.3+/-0.4 l/min/m2, in 30-39 years 3.3+/-0.5 l/min/m2, in 40-49 years 3.1+/-0.5 l/min/m2, 50-59 years 3.0+/-0.4 l/min/m2 and >60 years 3.0+/-0.4 l/min/m2.
There was no difference in CI between athletes and age-controlled healthy subjects. CI in CHF patients (2.3+/-0.6 l/min/m2) was lower compared to the healthy population (p<0.001).
There was a weak correlation between CI and EF in CHF patients (r2=0.07, p<0.001) but CI did not differ between patients with NYHA-classes I-II compared to III-IV (p=0.16) or patients with or without hospitilazations the previous year (p=0.80). In vitro phantom validation showed low bias (-0.8+/-19.8 ml/s) and in vivo validation in 25 subjects showed low bias (4.5+/-9.0 ml) between pulmonary and aortic flow/heart beat.
: CI over a wide age range in healthy subjects are presented and can be used as reference values for CMR.
CI decreases in healthy subjects with age but does not differ between males and females. We found no difference in CI between athletes and healthy subjects but CI was lower in patients with congestive heart failure.
Author: Marcus CarlssonRuslana AnderssonKarin Markenroth BlochKatarina Steding-EhrenborgHenrik MosénFreddy StåhlbergBjörn EkmehagHåkan Arheden Credits/Source: Journal of Cardiovascular Magnetic Resonance 2012, 14:51
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