Concealed ventricular premature complexes in a population sample

One hundred fifty patients were analyzed with a random sample of patients whose Holter recordings indicated ventricular premature complexes (VPCs). Thirty-five patients (23%) had more than 30 VPCs/hour. Of these 35 patients, 19 had concealed VPCs. This represents 54% of the patients with more than 30 VPCs/hour and 13% of the total sample of 150 patients with VPCs. The most common type of concealed VPCs was the classic concealed bigeminy (S = 2n - 1), which was found in 10 of 19 patients (52%) whose electrocardiograms and patterns were characteristic of concealed VPCs. This was followed by the "even variant" 2n in 5 patients (26%), concealed trigeminy (S = 3n - 1) in 1 (5%), the 3n - 2 variant in 1 (5%) and the "interpolated variant" of 1 + (2n - 1) in 1 (5%). One patient showed a conversion from 2n - 1 to 2n.