Characteristics of ventricular premature contractions and their clinical course.

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