Usefulness of rest and forced perfusion scintigraphy (SPECT) to evaluate cardiotoxicity in acute carbon monoxide poisoning.

The aim of the study was to evaluate myocardial perfusion in acute carbon monoxide poisoned patients using rest and stress Tc 99m-MIBI SPECT scintigraphy. There were 29 study patients (15 men and 14 women) aged from 14 to 46 years poisoned acutely with CO at home. Measurement of COHb, blood lactate level, duration of exposure and ECG examination were performed on admission to the Clinic. The enzymes activity (ALT, AST, CBK) were evaluated after 24 hours. The first rest Tc99m-MIBI SPECT was performed in all patients two to five days after intoxication. Fifteen of the patients underwent the control examination: stress and rest scintigraphy six months after CO exposure. Moving track exercise according to the Bruce protocol was used in each the patients. The control rest scintigraphy was performed 48 hours after exercise. Abnormal, differently intensified scans were noted in all the subjects: 5 patients had a I degree of pathological changes, 7 patients had II degree, 16--III degree and 1 patient had a IV degree of pathological changes. In 14 of the patients with pathological scintigraphic scans the normal EKG curves were noted. The mean COHb level was 35.0 +/- 7.22%, the blood lactate concentration was 4.4 +/- 3.7 mmol/L. The average duration of exposure was 108.4 +/- 163.9 min. Effort related ischemia was not noted in 10 of the patients who underwent control examination. An improvement in rest scintigraphic scans was stated in 12, and no changes were observed in 3 of the controlled patients. Deterioration was not found in any patient. No correlation between ECG results and scintigraphic image of myocardium was found. Tc 99m-MIBI SPECT scintigraphy is a more sensitive method than electrocardiography and measurement of enzymes activity for the evaluation of CO cardiotoxicity in acute poisoning. The method enables evaluation of the localization and disease extent.