HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nordrehaug, J. E. Articles by Vik-Mo, H. Search for Related Content PubMed PubMed Citation Articles by Nordrehaug, J. E. Articles by Vik-Mo, H.

Effects of Heart Rate on Myocardial Thallium-201 Uptake and Clearance

Department of Clinical Physiology, University of Bergen, Haukeland Hospital, 5021 Bergen, Norway

Correspondence: For reprints contact: Jan Erik Nordrehaug, MD, PhD, Dept. of Clinical Physiology, University of Bergen, Haukeland Hospital, 5021 Bergen, Norway.

ABSTRACT

The effects of heart rate on the myocardial uptake and clearance of ²⁰¹Tl were studied prospectively in seven healthy men, mean age 43 ± 7 (s.d.) yr. Initial and delayed (3 hr) thallium images were obtained in three views after three bicycle exercise tests: to maximal, 80% and 60% of predicted maximal heart rate. The mean of three views initial myocardial ²⁰¹Tl uptake was higher at maximal than at both 80% and 60% of predicted maximal heart rate, being 81% (p < 0.01) and 60% (p < 0.01) of maximal activity, respectively. The myocardial activity in the delayed images was identical. There was a linear relationship between heart rate and the initial myocardial activity, r = 0.86 (p < 0.001). The mean (range) ²⁰¹Tl clearance was 58% (51–65), 47% (34–56), and 34% (22–49) (all differences p < 0.01), respectively. Concordance among the three individual views in estimating clearance was best for the highest exercise level. There was a linear relationship between heart rate and clearance, r = 0.80 (p < 0.001). Clearance was altered by only 1.67 x 10%/heart bpm (0.024 hr/heart beat). Clearance in the liver, spleen and lungs increased at submaximal exercise levels. Thus, a linear relationship between heart rate and clearance is the result of changes in the initial exercise myocardial ²⁰¹Tl activity. Submaximal exercise may reduce reproducibility of clearance estimation, and the change of myocardial clearance with heart rate seems less than previously suggested.