XXXX for the treatment of refractory complex @entity1540 .

@entity1 @entity296 @entity1165 @entity101 @entity137 @entity3454 @entity741 @entity1540 @entity340 @entity943 @entity2779
The results of therapy with @entity2779 were evaluated in 45 @entity1 with complex @entity1540 that had been refractory to a mean of 3.8 antiarrhythmic drugs. The cardiac diagnoses were @entity741 (in 16 @entity1 ), @entity296 (in 7), @entity3454 (in 7), @entity3454 (in 7), idiopathic @entity1540 (in 6), @entity340 (in 5), and @entity101 (in 4). The frequency of @entity1540 was established after therapy with antiarrhythmic agents had been discontinued. @entity1 then received @entity2779 during a dose-ranging protocol. An effective response was defined as a reduction in total @entity1540 of 80% or more. During dose ranging, therapy failed in four @entity1 because of side effects, in eight because of a reduction in @entity1540 of less than 80%, and in three because of an aggravation of the @entity943 . Thirty @entity1 had a reduction in total @entity1540 of 80% or more. During a mean follow-up of 12.4 months, therapy failed in 1 @entity1 because of sustained @entity1165 and in 7 because of intolerable side effects; 22 @entity1 continued to receive @entity2779 . PR and QRS intervals were significantly prolonged (P = 0.001), but the corrected QT interval and the heart rate were unchanged. The mean trough plasma level of @entity2779 associated with an effective response was 756 ng/ml, and that associated with intolerable side effects was 920 ng/ml. Thus, in @entity1 with refractory complex @entity1540 , @entity2779 was effective and well tolerated initially in 67% of @entity1 and during long-term administration in 49%, and @entity137 was minor in most @entity1 .
