UTILITY OF LEFT VENTRICULAR FLOW
PROPAGATION VELOCITY DURING DOBUTAMINE STRESS ECHHCARDIOGRAPHY. C Young*, E Hassan, M Milne, P Bridgman. Department of Cardiology, Christchurch Hospital Christchurch,New Zealand Left ventricular flow propagation velocity
is a new tool for assessing diastolic function using colour Doppler M-mode. We
studied flow propagation velocity during dobutamine stress echocardiography
(DSE). 28 consecutive patients (18 males) of age range 22 to 80 years (median
64) undergoing DSE were studied. Patients were classified by whether or not
baseline left ventricular function was impaired and by the presence or absence
of inducible ischaemia. Under resting conditions there was a trend
towards higher flow propagation velocity in those with normal left ventricular
systolic function compared to those with impaired systolic function (46 +/-21
cm/s and 34 +/-13 cm/s, p=0.09). At maximal dobutamine stimulation those
patients with normal baseline left ventricular systolic function and no evidence
of inducible ischaemia had significantly higher flow propagation velocity than
those with normal function but inducible ischaemia (131 +/-52 cm/s versus 60
+/-27 cm/s, p=0.04). In patients with impaired baseline left ventricular
systolic function there was no significant difference in flow velocity
propagation between those that had inducible ischaemia and those that did not
(55 +/- 18 cm/s and 66 +/- 69 cm/s respectively). There was also no significant
difference between those that had ischaemia and normal systolic function and
those with ischaemia and abnormal systolic function. None of the subjects with
inducible ischaemia (irrespective of resting left ventricular function) had
peak flow propagation velocity greater than 100 cm/s. In those with no inducible
ischaemia there was, however a wide spread of values both above and below this
figure. This study suggests that flow propagation
velocity during DSE is influenced by both inducible ischaemia and resting left
ventricular systolic function. We did not find flow propagation velocity
sufficiently discriminatory to be a useful adjunct in detecting ischaemia.
