engleski

Effects of rest and excercise on cardiac volumes determinations by count-based method from Tc99m in vivo and modified in vivo / iv vitro red blood cells (RBC)equilibrium gated ventriculography.

The purpose of this study was to investigate the changes in blood activity during rest, exercise and recovery, and to determine its influence on left ventricular (LV) volume detemtination using the count-based method requiring blood sampling. Forty patients underwent rest-stress radionuclide ventriculogaphy ; Tc-99m was used in 13 patients to label HSA (Group I), and RBC in 17 patients (Group II) in vivo, and in ten patients (Group III) in vivo/in vitro. LV volumes were determined by a count-based method using blood samples obtained during rest, peak exercise and after recovery. In Group I at stress, the blood activity decreased by 12.6 t 5.4%, p<0.05, as compared to the rest level, and increased by 25.1 t 6.4%, p<0.001, and 12.8 +/- 4.5%, p<0.05, above the resting level in Groups II and III, respectively. This had profound effects on LV volume determinations if only one rest blood aliqaot was used: during exercise, the LV volumes significantly decreased by 22.1 +/- 9.6%, p<0.05, in Group I, whereas in Groups II and III it was significantly overestimated by 32.1 +/- 10.3%, p<0.001, and 10.7 +/- 6.4%, p<0.05, respectively. Changes in blood activity between stress and recovery were not significantly different for any of the three Groups. The use of only a single blood sample as volume aliquot in rest-stress studies leads to erroneous estimation of cardiac volumes due to significant changes in blood radioactivity during exercise and recovery.

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nije evidentirano