title: Fetal longitudinal myocardial function assessment by anatomic M-mode.
abstract: OBJECTIVE
  To evaluate the feasibility of offline anatomic M-mode (AMM) to study fetal atrioventricular annulus long-axis displacement (LAD) and compare its performance against real-time conventional M-mode (MM).
  
  
  METHODS
  Paired AMM and MM LAD studies were recorded prospectively in 54 fetuses, and performance was compared. Insonation angles were less than 30° in all but 4 cases. The overall feasibility of AMM was tested in a composite total sample of 91 normal singleton pregnancies (median gestational age 23⁺⁶ weeks, range 12-36). AMM LAD was measured by placement of a virtual M-mode line on digitally stored raw data of fetal 4-chamber video loops. We studied annulus LAD at the lateral mitral (left ventricle; LV), proximal mitral (intraventricular septum; IVS), and lateral tricuspid (right ventricle; RV) myocardial segments. We compared LAD and its regression with gestational age measured using both methods in paired studies and AMM in the whole cohort.
  
  
  RESULTS
  Annulus LAD was measured using AMM, in all cases and segments, irrespective of cardiac axis alignment to the ultrasound beam. Good correlation existed between AMM and MM (RV r = 0.901, LV r = 0.899, IVS r = 0.815, p < 0.001). AMM recorded higher LAD values than MM in RV [mean 6.17 (SD 1.46) vs. 5.82 (SD 1.74) mm, p = 0.002] and LV [mean 4.18 (SD 1.11) vs. 3.98 (SD 1.12), p = 0.007]. Both methods showed LAD in RV > LV > IVS and a significant gestational increase in LAD values in all segments (p < 0.001)
  
  
  CONCLUSIONS
  AMM permits offline evaluation of fetal longitudinal myocardial function in routinely obtained 2D fetal heart images with similar values to conventional MM in paired studies recorded <30°.
authors.affiliation: Pediatric Cardiology Unit, Department of Pediatrics, University Hospital Heraklion, Heraklion, Greece. germjohn@med.uoc.gr
authors.forename: Ioannis
authors.initials: I
authors.lastname: Germanakis
authors.forename: Spyridon
authors.initials: S
authors.lastname: Pepes
authors.forename: Stavros
authors.initials: S
authors.lastname: Sifakis
authors.forename: Helena
authors.initials: H
authors.lastname: Gardiner
mesh_terms: D015331:Cohort Studies; D004452:Echocardiography; D005240:Feasibility Studies; D005260:Female; D005865:Gestational Age; D006321:Heart / Q000196:embryology* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology; D009200:Myocardial Contraction; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D014261:Tricuspid Valve / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014741:Video Recording