English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Cellular electrophysiological consequences of acute ischemia superimposed on healed myocardial infarction were studied in isolated, coronary-perfused cat left ventricles 2-4 months after ligation of multiple distal tributaries of the left anterior descending and circumflex coronary arteries. Oxygenated Tyrode's solution was perfused through the left anterior descending and circumflex coronary arteries, and the preparations were superfused with Tyrode's solution gassed with 95% N2-5% CO2. Transmembrane action potentials were recorded from the endocardial cells in normal and infarcted zones. There were no significant differences in measured action potential variables and refractory periods between cells in the normal and infarcted zones before acute ischemia. When coronary perfusion was discontinued ("ischemia"), resting potential, action potential amplitude, and action potential duration were reduced, and the refractory period was shortened progressively in cells of the normal zone. However, the action potential changes were less prominent, and the refractory period was unchanged in cells in the infarcted zone. As a result, there were significant differences in resting membrane potential, action potential amplitude, action potential duration, and refractory period between cells in the normal and infarcted zones at 10 minutes of ischemia. These differences became larger as the ischemic period was prolonged. Spontaneous rapid ventricular activity was observed during the last 20-30 minutes of ischemia in four of eight preparations with healed myocardial infarction, whereas no spontaneous rapid ventricular activity was recorded in any of six normal heart preparations. Our data suggest that superimposition of acute ischemia on healed myocardial infarction produces electrophysiological inhomogeneities that may enhance arrhythmogenesis.

Cellular electrophysiological changes during ischemia in isolated, coronary-perfused cat ventricle with healed myocardial infarction.