Effect of tobacco abuse on pulmonary thallium uptake during exercise myocardial perfusion scintigraphy.

To determine the influence of tobacco abuse on thallium 201 lung uptake during exercise, we examined 185 consecutive subjects with normal myocardial perfusion scans and without electrocardiographic evidence of left ventricular hypertrophy. The subjects were divided into two groups: group 1 subjects (n = 60) had histories of smoking and group 2 subjects (n = 125) were nonsmokers. Eighty-eight percent of group 1 subjects and 92% of group 2 subjects were examined using single-photon emission computed tomography and the remaining patients underwent planar imaging. 201Tl lung and heart activities were quantified from the immediate anterior planar images that were obtained in all subjects and reported as lung to heart ratio (L/H). 201Tl L/H in smokers (0.39 +/- 0.11) was significantly higher (P < 0.05) than in nonsmokers (0.34 +/- 0.06) when subjects who achieved 85% of the target heart rate were compared. In conclusion, 201Tl L/H was higher in smokers than in nonsmokers when subjects who achieved 85% of the target heart rate and had no myocardial perfusion defects were compared.