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[Evaluation of anti-arrhythmia agents in the animal model]
1Herz-/Kreislauf-Pharmakologie, Knoll AG, Ludwigshafen.
Abstract:
In view of the results of CAST, researchers working in the field of experimental arrhythmia have been increasingly focusing on the quest for new anti-arrhythmic modes of action and ways of detecting pro-arrhythmic properties of antiarrhythmic drugs at an early stage. Here, the experimental methods available play a particularly important role. While trying to assess anti-arrhythmic effects without investigating electro-physiological parameters in isolated tissue would be inconceivable, the degree to which the results of in vitro studies can be transferred to the intact organism is limited because of the complex nature of the arrhythmias. Of the various existing in vivo models, the most commonly employed are those in which arrhythmia is induced after experimental surgical interventions causing ischemia and infarction, followed by reperfusion. This shows that researchers are striving to "create" pathophysiologically-defined conditions and, as far as possible, a pathophysiological situation which is similar to that in the patient. Guidelines were laid down for this model complex in the Lambeth Conventions (1988) in order to improve uniformity of the methods and better comparability of the results generated by different investigators. Of the existing arrhythmia models, the ventricular re-entry arrhythmia model after myocardial infarction triggered by programmed stimulation, which was devised by Spear/Moore (1983), has proven to be particularly useful in the assessment of antiarrhythmics and is used by many researchers. Class II and III antiarrhythmics can be identified reliably by this method, whereas class I antiarrhythmics are mostly inconspicuous.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Researchers are developing new methods to detect pro-arrhythmic drug properties early. The ventricular re-entry arrhythmia model after myocardial infarction is a key in vivo tool for assessing anti-arrhythmic drugs.
Area of Science:
- Cardiovascular Research
- Pharmacology
- Experimental Medicine
Context:
- Following CAST results, focus shifts to novel anti-arrhythmic mechanisms and early detection of pro-arrhythmic drug effects.
- In vitro electrophysiological studies have limitations in predicting in vivo arrhythmia complexity.
- In vivo models simulating pathophysiological conditions like ischemia, infarction, and reperfusion are crucial.
Purpose:
- To review and highlight the importance of experimental methods in anti-arrhythmic drug research.
- To emphasize the utility of in vivo models over in vitro studies for complex arrhythmia assessment.
- To discuss the effectiveness of specific arrhythmia models in evaluating anti-arrhythmic drug properties.
Summary:
- The ventricular re-entry arrhythmia model post-myocardial infarction, induced by programmed stimulation, is highly effective for evaluating anti-arrhythmic drugs.
- This model reliably identifies Class II and III antiarrhythmics.
- Class I antiarrhythmics are less reliably detected using this specific model.
Impact:
- Improves the standardization and comparability of anti-arrhythmic drug research through established guidelines like the Lambeth Conventions.
- Facilitates the early identification of potentially harmful pro-arrhythmic drug effects.
- Enhances the development of safer and more effective anti-arrhythmic therapies by refining preclinical assessment models.