Functional Cardiac Differences in Young Adults Born Premature, Assessed by MRI

PurposePremature birth, defined as birth prior to 37 weeks of gestation, affects 1 in 10 births in the United States. Young adults born preterm have been shown to have impaired gas exchange and diminished aerobic capacity, but little is known about the functional cardiac differences at rest and in exercise. The intent of this study is to quantify the cardiac differences between preterm‐born young adults and term‐born young adults through measurements of heart rate (HR), stroke volume (SV), cardiac output (Q), end diastolic volume (EDV), end systolic volume (ESV), and ejection fraction (EF).MethodsFive young adults born preterm (PT) (age 25–28, birthweight <1500g, gestational age <32 weeks) and 5 age‐matched young adults born full term (CT) (gestational age 38–40 weeks) completed supine steady state exercise on an exercise stepper while in a magnetic resonance imaging (MRI) machine with continuous measurement of cardiac variables. Q and SV were indexed to body surface area (BSA (m2), Qi and SVi). Statistical analysis was done using multiple t‐tests.ResultsAt rest, there was no difference in PT compared to CT in SV (91.2 ± 5.8 v 99.0 ± 20.7, p=0.44), SVi (53.8 ± 5.2 v 52.0 ± 7.5 ml, p=0.67), EDV (143.6 ± 17.0 v 172.8 ± 30.5, p=0.1), ESV (52.5 ± 12.7 v 73.7 ± 20.1, p=0.08), and EF (63.9 ± 4.6 v 57.5 ± 7.4, p=0.14). Compared to CT, PT had significantly higher Q (7.2 ± 0.46 v 5.9 ± 0.82, p=0.02), Qi (4.2 ± 0.37 v 3.1 ± 0.17, p=0.0003), and HR (78.8 ± 6.6 v 60.8 ± 8.5, p=0.006) at rest. Exercise data yet to be analyzed.ConclusionYoung adults born preterm exhibit lower maximal aerobic capacity than age‐matched controls. Despite difficulty with exercise, PTs have higher Qi at rest, suggesting a decreased ability to augment Q in response to increasing metabolic demand, which may reduce their ability to exercise at higher intensities. This inability to adequately increase Q appears to be driven by a higher HR at rest. Both SV and HR increase during exercise, but HR of PTs reaches max at an earlier time point, which restricts further increase of Q.Support or Funding InformationNIH/NHLBI R01 HL115061This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.