Myocardial performance assessment in neonates by one-segment strain and strain rate analysis by tissue Doppler - a quality improvement cohort study
- 1Department of Paediatrics, Vestfold Hospital Trust, Tønsberg, Norway
- 2Department of Cardiology, St Olavs Hospital, Trondheim, Norway
- 3Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
- 4Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- 5Department of Neonatal Intensive Care, Oslo University Hospital, Ullevål, Oslo, Norway
- Correspondence to Dr Eirik Nestaas;
- Received 11 June 2012
- Accepted 12 July 2012
- Published 24 August 2012
Objectives To investigate one-segment strain and strain rate indices as measures of myocardial performance in asphyxiated term neonates.
Design Quality improvement cohort study.
Setting Newborns admitted to a neonatal intensive care unit at a Norwegian University Hospital for perinatal asphyxia and non-asphyxiated newborn recruited from the maternity ward at the same hospital.
Participants Twenty asphyxiated and 48 non-asphyxiated term neonates.
Primary outcome measure Strain and strain rate indices and repeatability measures. One-segment longitudinal strain and strain rate by tissue Doppler were assessed on days 1, 2 and 3 of life in nine heart walls. Repeatability was compared against measurements from two-segment analyses previously performed in the same images.
Results The 95% limits of agreement were significantly better for the one-segment than two-segment repeatability analyses, the inter-rater peak systolic strain (PSS) was (−3.1, 3.3) vs (−11.4, 18.3)%, the inter-rater peak systolic strain rate (PSSR) was (−0.38, 0.40) vs (−0.79, 1.15)/s, the intra-rater PSS was (−2.5, 2.6) vs (−8.0, 9.8)% and the intra-rater PSSR was (−0.23, 0.25) vs (−0.75, 0.80)/s (p<0.05). The myocardial performance was lower in the asphyxiated neonates (indices closer to zero) than in the non-asphyxiated neonates, PSS was −17.8 (0.6) (mean (SEM)) vs −21.2 (0.3)%, PSSR −1.43 (0.08) vs −1.61 (0.03)/s, early diastolic strain rate 1.72 (0.11) vs 2.00 (0.11)/s and strain rate during the atrial systole 1.92 (0.17) vs 2.27 (0.10)/s (p<0.05), despite no difference in fractional shortening (29.0 (0.5) vs 29.1 (1.0)%) (p>0.05).
Conclusions One-segment strain and strain rate assessed the reduced myocardial performance in asphyxiated neonates with significantly improved reproducibility as compared with two-segment analysis and was therefore more feasible than two-segment analyses for assessment of myocardial performance after perinatal asphyxia.
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