Abstract

Accelerated recovery, as manifested by shortening of the effective refractory period after coronary artery ligation, occurred at either the epicardial or endocardial surface or both in 11 of 13 animals tested with a mean shortening of 15.7 per cent at the epicardial and 13 per cent at the endocardial levels. These changes are attributed to severe anoxia and are believed to be limited to the ischemic area, since studies in the periphery of an infarcted zone show no significant changes in the first 3 hours. In one instance a minor acceleration of recovery was found after 3 hours at the endocardium. All studies showed a final period of delayed recovery. It is felt that this probably reflects a prolonged duration of the membrane action potential during the later stages of myocardial infarction. This is supported by both experimental and human electrocardiographic data which show prolongation of the Q-T interval in association with deeply inverted T waves following the period of acute injury. Transmural temperature studies after coronary artery ligation showed a prompt fall in 2 studies out of 7 and no acute change in the others. Irrigating the pericardial sac with warm Ringer's solution reversed the pre-existing transmural temperature gradient, caused the T waves in epicardial leads to change from negative to positive, and reduced the duration of the effective refractory period at both the endocardial and epicardial surfaces, especially the latter. During the time that the T waves were upright, recovery was completed earlier at the epicardial than at the endocardial surface.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.