Predictive value of pulmonary venous flow patterns in detecting mitral regurgitation and left ventricular abnormalities

OBJECTIVE

To determine whether abnormalities in pulmonary venous flow (PVF) patterns detected by transesophageal echocardiography (TEE) correlate with the severity of mitral regurgitation (MR) or the presence of left ventricular (LV) abnormalities, and to demonstrate whether a normal PVF pattern predicts the absence of structural heart disease.

DESIGN

Review of all TEEs performed at a tertiary care cardiac hospital over a four-month period.

PATIENTS

Among 195 studies, 100 fulfilled the inclusion criteria.

RESULTS

PVF was categorized into three patterns, which have been described previously. A normal PVF pattern predicted the absence of clinically significant MR with a high degree of certainty (positive predictive value [PPV] 98%). However, it did not predict the absence of structural cardiac disease (PPV 64%). A PVF pattern that showed systolic flow reversal was strongly predictive of the presence of significant MR (sensitivity 86%, specificity 100%, PPV 100%). The frequency of significant MR in this group was much higher than in patients with normal PVF (12 of 12 versus one of 66, P<0.0001). Patients with a blunted PVF pattern were more likely than patients with a normal PVF to have LV abnormalities (18 of 22 versus 23 of 66, P=0.0005). However, a blunted PVF was not associated with clinically significant MR.

CONCLUSIONS

A normal PVF does not rule out the absence of LV abnormalities but confirms the absence of significant MR. Systolic flow reversal is highly predictive of the presence of significant MR. A blunted PVF is more likely to be associated with LV abnormalities than with MR and has limited usefulness in the diagnosis of significant MR.

Rearrangements at a hobo element inserted into the first intron of the singed gene in the unstable sn49 system of Drosophila melanogaster

The cytological structure of the X chromosome and the DNA organisation of the singed locus were examined in five singed bristle mutants of Drosophila melanogaster. These mutants are all derived from the unstable mutant singed-49, isolated from a wild population in the Russian Far East in 1975. Rearrangements were found at a site within the first intron of the singed gene, where a hobo element is inserted in these mutants. One rearrangement, which is associated with a strong bristle phenotype, has an inversion between 2D and the location of singed at 7D, which separates the singed promoter from the singed coding region. Two phenotypically wild-type derivatives have smaller rearrangements within the first intron which do not appear to interfere with singed expression. Two derivatives with bristle phenotypes have more complex rearrangements, and one of them shows a dominant or antimorphic phenotype. DNA blotting and in situ hybridisation experiments show that, in addition to these rearrangements at a hobo element inserted at singed, other hobo elements in these strains have been mobilised. This system is therefore similar to others in which functional hobo elements continue to transpose, resulting in elevated rates of mutation and chromosome rearrangement.