Multiple comparison of several antiarrhythmic agents by acute oral drug testing in patients with chronic ventricular arrhythmias

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Abstract
This study addresses the question of the choice of treatment for the individual patient with chronic ventricular arrhythmias. Acute oral drug testing offers a pragmatic approach to the rapid selection of the drug with the best efficacy/side-effect ratio by allowing multiple comparisons within the same patient. Forty patients with chronic ventricular arrhythmias received a single oral dose of the following antiarrhythmic drugs: flecainide 200 mg, propafenone 450 mg, disopyramide 300 mg, mexiletine 400 mg, tocainide 800 mg, verapamil 160 mg, propranolol 120 mg. Criteria for efficacy were suppression of complex ventricular arrhythmias and a > 90% reduction in premature ventricular beats lasting for at least 2 h. An antiarrhythmic effect was achieved with each of the drugs in the following percentages of patients: flecainide 69·;4%, propafenone 67·5%, disopyramide 54·;8%, mexiletine 45·2%, tocainide 31·;3%, verapamil 31·3%, propranolol 12·5%. In no case was worsening of arrhythmia observed. At the end of the acute testing phase, the drug that had proved most effective in each patient was administered at a full dosage for 72 h. A concordant response between the two phases was observed in 80% of patients and was as high as 89% when the analysis was limited to flecainide and propafenone. This study shows the feasibility and practical advantages for patient management of a multiple comparison of antiarrhythmic drugs by acute oral drug testing. It also provides, in a non-invasive cost-effective manner, unique insights into the complex relationship between drug characteristics, individual responses and clinical efficacy.