Characteristics of XXXX and their clinical course.

@entity1 @entity204 @entity1540
One hundred @entity1 with frequent (> 1,000 beats/day) @entity1540 ( @entity1540 ) were followed for 4 years. All of the @entity1 , except those with @entity204 (n = 8), were classified into 3 groups based on their outcome. Group A consisted of 29 @entity1 with idiopathic @entity1540 who survived the study period. Group B consisted of 49 @entity1 with underlying diseases who survived the study period. Group C consisted of 14 @entity1 who suffered @entity204 . There was no significant difference in the daily number of @entity1540 . However, groups B and C had more @entity1 with Lown grade 4a or 4b @entity1540 than group A. The mean coupling interval was significantly longer in group C than in group A, and the standard deviation of the coupling interval was significantly larger in group C than in group A. Forty @entity1 underwent serial Holter monitorings to assess changes in the number of @entity1540 . @entity1540 spontaneously decreased in 13 @entity1 , while the other 27 @entity1 continued to have frequent @entity1540 . Most of these 13 @entity1 were classified as Lown grade 2. The results suggest that in @entity1 with frequent @entity1540 , longer and more varied coupling intervals may predict a poor prognosis, and Lown grade 2 may predict a spontaneous regression.
