99-m technetium (Dupont Cardiolite) investigations in postinfarction patients with Holter-checked silent ischaemia.

Sixteen middle-aged, normotensive, slightly overweight male patients with previous myocardial infarction were studied during Holter-checked silent myocardial ischaemia. As reference, stress and late 201-T1 scintigraphy served for comparison with Cardiolite-MIBI silent ischaemic perfusion scan, both carried out in planar mode. The circumferential profiles differed in 9 cases, on region of interest basis the segment number difference was 10, but the late distribution segment number was near to both ischaemic numbers. The quantitative scores were distinctive (ratio 133-128/103) indicating the silent ischaemia appeared in the peri-infarct area. The silent ischaemic MIBI and stress 201-T1 ischaemic score difference was reduced by means of repeated SPECT investigation. With gated radionuclide ventriculography there was -4.3% difference between the left ventricular ejection fractions, measured with first pass MIBI technique during silent ischaemia and afterwards in basal state. The impairment of the left ventricular function was reflected on the stroke pattern of our Holter-based radiocyclogram, as well. Taking the 43.7-48.0 = -4.3% "ischaemic shift" into consideration it was a close correlation (r = 0.90) between the two kinds of ejection fraction determination. The major rhythm failures (occurring during the 24 h Holter monitoring) decreased to a higher degree the left ventricular ejection fraction than silent ischaemia or silent ischaemia and minor rhythm failure together (38-42-50%).