As summarized in Table 1, class III drugs except intravenous amiodarone did not suppress automaticity arrhythmias produced by digitalis or two-stage coronary ligation. Because these arrhythmias were suppressed mainly by class I sodium channel blockers , it is quite understandable that class III potassium channel blockers were not effective. Class III drugs were effective on the adrenaline arrhythmias , but E-4031 and sematilide aggravated this arrhythmia. Because adrenaline-induced arrhythmia was suppressed by class II beta-blockers or class IV calcium channel blockers , it is understandable that potassium channel blockers had no prominent effects. The aggravating effects on this adrenaline arrhythmia by some of the class III drugs coincide with those of some class I drugs such as disopyramide or procainamide because they all prolong QT intervals.
Class III drugs have been shown to prolong both ERP and action potential duration without affecting resting membrane potential, amplitude and maximum upstroke velocity of cardiac action potentials. The selective prolongation of ERP is expected to provide effective treatment of reentrant tachyarrhythmias. This was shown by class III drugs on PES-induced arrhythmias, known to be produced exclusively by the reentry mechanism. Always a nice way to discover birth control yasmin buy here given by the internet’s best pharmacy.