DETECTION AND LOCALIZATION OF EARLY DIASTOLIC FORCES WITHIN THE LEFT-VENTRICLE FROM INFLOW JET DYNAMICS - A COMPARISON BETWEEN NORMAL SUBJECTS AND PATIENTS WITH DILATED CARDIOMYOPATHY

We studied the properties of the jet of blood entering the left ventri cle from the left atrium during early diastole in 32 patients with dil ated cardiomyopathy, and 24 normal subjects of similar age. The diamet er of the jet was measured from the cross-sectional color Doppler imag e and its cross-sectional area (JA) was derived. Pulsed Doppler record s of flow velocity were made at 1-cm intervals into the ventricle from the mitral ring. Peak (Vp) and mean (Vm) E wave velocity and time vel ocity integral (TVI) were determined. At any level in the ventricle, t herefore, the early diastolic volume of blood remaining in the jet, i. e., the flow time integral, is given by JA . TVI; the local flow rate, Q, by JA . Vm; and jet momentum along the long axis of the ventricle by Q . Vp. In normals, the jet cross-sectional area fell from 5.9 (1.3 ) cm(2) at the mitral ring to 4.9 (0.7) cm(2) at 4cm (P < 0.05), but t he flow time integral fell proportionately more, from 46.0 (15.2) mi a t the ring level to 15.9 (3.4) mi at 4cm (P < 0.01). Axial momentum fl ux was 44 (13) x 10(2)cm(4)s(-2) at the ring level, falling to 28 (10) x 10(2) cm(4)s(-2) at 4cm (P < 0.01). In dilated cardiomyopathy, the jet cross-sectional area was much smaller than normal, 1.9 (0.8) cm(2) at the ring level, and it remained effectively constant, being 2.0 (0 .9) cm(2) at 6cm (P < 0.01 vs normals). The same applied to the flow t ime integral, which was reduced at the ring level (18.0 (10.3) mi P < 0.01 vs normal), and was unchanged at 5cm. Axial momentum flux was hig her than normal, 72 (33) x 10(2)cm(4)s(-2) at ring level (P < 0.01 vs normal), was unchanged at 4cm, and fell at 6cm to 43 (18) x (2)cm(4)s( -2) (both P < 0.01 vs normal). Thus, axial momentum was rapidly lost f rom the incoming jet in the normals, prmarily due to loss of mass, sug gesting forces acting perpendicularly to the ventricular long axis. In patients with dilated cardiomyopathy, the cross-sectional area of the jet was much smaller, less mass was lost from the jet, and momentum w as maintained at least 4cm into the cavity, falling only slowly therea fter, suggesting that lateral forces are much less well developed in t hese patients.