OP04.07: Fetal heart examination in first trimester using SlowflowHD versus Doppler

In recent years, advancements in technology have revolutionised the field of first trimester ultrasound, enabling the visualisation of fetal heart and the detection of cardiac malformations at an early stage, with a current detection rate of 50%. However, Doppler examination of the fetal heart in first trimester screening has its limitations, such as the inability to visualise small-calibre vessels or the necessity for appropriate settings to ensure accurate colour confinement. Addressing these limitations, GE HealthCare has introduced a new application called SlowflowHD which aids examiners by enhancing the visualisation of small-calibre vessels and detecting even low velocities in blood vessels. The assessment of the fetal heart with SlowflowHD technology aimed to evaluate anatomical structures of the fetal heart and to identify any cardiac anomalies discernible in the first trimester. Subsequently, to validate the initial assessment, patients underwent re-evaluation with Doppler examination between 16 and 23 weeks. This prospective study included 172 patients pregnant with gestational ages from 11 weeks to 13 weeks and 6 days, or Crown–rump length (CRL) between 45 and 84mm and 6 patients referred to our clinic for a second opinion due to Nuchal Translucency (NT) > 3.5 mm. SlowflowHD was successfully used for fetal heart examination in all cases, adhering to standard sections of ISUOG guidelines: the four-chamber view, the left and right ventricular outflow tracts and the three-vessel view. Thirty-one examinations were performed transvaginally. In 172 patients, two cases of cardiac anomalies were suspected, all confirmed in subsequent re-evaluation and another 3 cases were confirmed as second-opinion, resulting in a 100% detection rate. SlowflowHD technology offers significant improvements in first trimester fetal heart examination by simplifying cardiac plane navigation and enhancing accuracy in anomaly detection. It is user-friendly, efficient, and provides detailed vascular visualisation, surpassing traditional Doppler techniques.