Tei index: the earliest detectable cardiac structural and functional abnormality detectable in Hb Bart's foetal edema

Premature death and still births are common in Hb Bart's foetal edema which carries significant risk to mothers. We aimed to identify early changes in cardiac structure and function in a cohort of HB Bart's foetuses, using Doppler echocardiography.

We studied 97 HB Bart's foetuses in different gestation groups; I (20-24 weeks),..., V (37-42 weeks) and compared them with age matched controls. We measured right and left atrial diameters as well as right and left ventricular diameters. From the Doppler filling and ejection velocities of the right and left ventricles we measured Tei index in 30 foetuses and compared them with age matched normal controls.

The four cardiac chamber dimensions were not significantly different from the respective controls (p=NS for all). The right atrial diameter was enlarged in groups II, III, IV and V (p<0.05 vs normal controls). The right ventricle was significantly dilated in group III, IV and V (p<0.05-0.01) compared with normals. The left atrium and left ventricle were enlarged in groups III and IV, respectively (p<0.05 vs normals). Transmitral and transtricuspid E/A ratio was significantly less than normal in groups III (p<0.01), IV (p<0.05) and IV (p<0.05). LV and RV fractional shortening and stroke distance of group IV and V were significantly less than the respective normals (p<0.05 for all). LV and RV Tei index increased progressively from 20-week gestation (p<0.05) with respect to controls.

In HB Bart's foetuses left and right ventricular asynchrony develop earlier than overt cavity dilatation and impairment of systolic function. The use of such markers of ventricular asynchronous function may play an important role in optimum management of these pregnancies.