The effect of preventive administration of melatonin on the arrhythmogenic substrate in the myocardium was studied in the rabbit model of acute ischemia/reperfusion in vivo. The animals treated with melatonin 60 min before ischemia induction had shorter median activation time compared to the control group (p=0.039), less pronounced shortening of repolarization durations in the ischemic zone during coronary occlusion (p=0.008), and more complete recovery of repolarization during reperfusion (p=0.027). In the melatonin group, the dispersion of repolarization was less than in the control group during both ischemic period (p=0.043) and reperfusion (p=0.038). Thus, preventive administration of melatonin mitigated the arrhythmogenic substrate in the heart under conditions of ischemia/reperfusion.

• Klíčová slova
• dispersion of repolarization, ischemia/reperfusion, melatonin,
• MeSH
• ischemická choroba srdeční farmakoterapie   patofyziologie   MeSH
• králíci MeSH
• melatonin terapeutické užití   MeSH
• reperfuzní poškození myokardu farmakoterapie   patofyziologie   MeSH
• srdce fyziologie   MeSH
• srdeční elektrofyziologie MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• melatonin MeSH

The effects of therapeutic or preventive-therapeutic administration of water-soluble echinochrome analog U-441 on arrhythmia severity assessed by a set of myocardial spatio-temporal depolarization and repolarization parameters were examined on the model of acute myocardial ischemia in cats. Coronary occlusion increased activation time and decreased repolarization time in the ischemic zone; in addition, it increased both global and borderline (local) dispersions of repolarization. The linear regression model showed that only activation time values measured at the initial state and at termination of occlusion were associated with total arrhythmia score during ischemia (regression coefficient β=0.338, 95%CI=0.074-0.602, p=0.015 and β=0.720, 95%CI=0.323-1.117, p=0.001, respectively). The study revealed no association between administration of echinochrome analog U-441 and arrhythmia severity.

• Klíčová slova
• cats, echinochrome analog U-441, ischemia, predictors, ventricular arrhythmias,
• MeSH
• antiarytmika izolace a purifikace   farmakologie   MeSH
• elektrokardiografie MeSH
• ischemická choroba srdeční farmakoterapie   patofyziologie   MeSH
• ježovky chemie   MeSH
• kočky MeSH
• koronární okluze chirurgie   MeSH
• modely nemocí na zvířatech MeSH
• myokard patologie   MeSH
• naftochinony izolace a purifikace   farmakologie   MeSH
• převodní systém srdeční účinky léků   patofyziologie   MeSH
• rozpustnost MeSH
• srdeční arytmie farmakoterapie   patofyziologie   MeSH
• stupeň závažnosti nemoci MeSH
• terapie neúspěšná MeSH
• voda chemie   MeSH
• zvířata MeSH
• Check Tag
• kočky MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiarytmika MeSH
• echinochrome A MeSH Prohlížeč
• naftochinony MeSH
• voda MeSH

Mature Wistar rats were exposed to intermittent hypobaric hypoxia (5000 m, 6 h/day, 30 sessions). This mode of adaptation enhanced heart tolerance to the arrhythmogenic action of 45-min coronary occlusion, but does not affect the infarction size/risk area ratio. In some series, the rats were exposed to more severe intermittent hypobaric hypoxia (7000 m, 8 h/day, 6 weeks) followed by 20-min coronary occlusion and 3-h reperfusion one day after the last hypoxia session. In this case, adaptation reduced the infarction size/risk area ratio and enhanced cardiac tolerance to the arrhythmogenic effect of reperfusion, but had no effect on the incidence of ventricular arrhythmia during ischemia. We found that the cardioprotective and antiarrhythmic effects of adaptation to an altitude of 7000 m and the antiarrhythmic effect of 5000-m adaptation were mediated via activation of K(ATP) channels.

• MeSH
• atmosférický tlak * MeSH
• cytoprotekce účinky léků   fyziologie   MeSH
• fyziologická adaptace účinky léků   fyziologie   MeSH
• hypoxie patologie   prevence a kontrola   MeSH
• imidazoly farmakologie   MeSH
• ischemické přivykání metody   veterinární   MeSH
• KATP kanály agonisté   fyziologie   MeSH
• krysa rodu Rattus MeSH
• myokard patologie   MeSH
• nadmořská výška MeSH
• potkani Wistar MeSH
• srdeční arytmie prevence a kontrola   MeSH
• thioamidy farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• imidazoly MeSH
• KATP kanály MeSH
• MCC 134 MeSH Prohlížeč
• thioamidy MeSH