title: Improvement of ST segment depression by gradual recruitment of collateral circulation.
abstract: The purpose of the present study was to document that the coronary collateral vessels do not open immediately upon the occurrence of myocardial ischemia. A multistage bicycle exercise was performed to determine a maximal tolerable work load until the onset of angina and significant ST segment depression in 10 patients with well-developed collateral circulation. On a different day, exercise with the maximal tolerable work load was repeated for a comparable exercise duration. In 2 of the 10 patients, anginal pain was gradually alleviated despite the continuation of exercise with fixed work load. The extent of ST segment depression at 3 min of exercise with fixed work load was 0.20 +/- 0.10 (SD) mV, significantly (p less than 0.05) greater than 0.16 +/- 0.08 mV at the end of exercise with fixed work load. In contrast, the rate-pressure product was smaller at 3 min than at the end of exercise with fixed work load (20,900 +/- 5,500 vs. 22,700 +/- 5,700 mm Hg.beats/min; p less than 0.05). In 5 patients without well-developed collateral circulation, the extent of ST depression changed in parallel with changes in rate-pressure product during exercise with fixed work load. Thus, it is concluded that the delayed collateral opening plays a critical role in the pathogenesis of myocardial ischemia in patients with a totally occluded coronary artery.
authors.affiliation: Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Fujita
authors.forename: T
authors.initials: T
authors.lastname: Hirai
authors.forename: A
authors.initials: A
authors.lastname: Ohno
authors.forename: K
authors.initials: K
authors.lastname: Miwa
authors.forename: H
authors.initials: H
authors.lastname: Asanoi
authors.forename: S
authors.initials: S
authors.lastname: Sasayama
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000503:physiopathology*; D003097:Collateral Circulation / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011999:Recruitment, Neurophysiological