Exercise training following myocardial infarction improves myocardial perfusion assessed by thallium-201 scintigraphy

Aim: We assessed the effects of a 6-week exercise programme on the thallium-201 myocardial perfusion characteristics of patients following myocardial infarction. Methods: Twenty-five patients presenting with a first acute myocardial infarction were randomised into two groups: (i) those undergoing a supervised exercise training programme over 6 weeks (n=15) and (ii) a control group who did not attend the exercise programme (n=10). All underwent three sequential stress thallium myocardial perfusion scans at 10 days, 6 weeks and 3 months after infarction. The stress conditions were identical on each occasion. The images were analysed using a polar plot with a computer assisted algorithm comparing stress and redistribution data. Values for extent, severity and percentage redistribution of the thallium images were generated. Results: A total of 29 perfusion defects were identified, 18 in the exercise group and 11 in the control group. Over 3 months in the exercise group the mean extent of the stress image defect fell from 109±64 to 95±51 pixels (P<0.05) while in the control group there was an increase from 133±57 to 144±57 pixels (P=ns). Stress defect severity fell in the exercise group from 581±417 to 494±346 S.D. (P<0.05) but increased in the control group from 765±494 to 877±543 S.D. (P=ns). On redistribution imaging in the exercise group a significant decrease was observed in both extent (94±56 to 76±43 pixels (P<0.05)) and severity (541±387 to 438±291 S.D. (P<0.05)) of the defects. However in the control group no significant change was observed for extent (125±54 to 125±52 pixels) or severity (745±485 to 820±503 S.D.) of the redistribution defects (P=ns). Reversibility of the defects increased slightly in both the exercise group (from 14.6±17 to 17.5±20%) and the control group (5.2±5 to 9.6 10%) (P=ns). Conclusion: Following myocardial infarction a 6-week exercise programme improves myocardial perfusion characteristics. An exercise programme should be integrated into cardiac rehabilitation protocols for patients after infarction.