A Shift from Class I to Class III Drugs in the Medical Treatment of Arrhythmias: Wishful Thinking?
Recently attention among clinicians and arthythmologists has shifted from the study of class I drugs acting on the Na+ channel to class III drugs or drugs prolonging the action potential duration. The immediate reason was the Cardiac Arrhythmia Suppression Trial (CAST) study (1989), which showed an increased mortality in patients treated for premature ventricular extrasystoles following myocardial infarction with drugs representative of the class I type . The fundamental question that should be answered is whether better results may be expected from the new approach of using drugs prolonging the action potential duration. Is this new hope justified?
KeywordsAction Potential Duration Outward Current Tail Current Cardiac Arrhythmia Suppression Trial Sodium Channel Blockade
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