The presence of any VPC was associated with a significantly higher risk for SCD (adjusted relative RISK = 3.0; p < 0.025). On the other hand, the presence of any VPC was not associated with any significant increase in the risk of non-SCD or of total deaths from CAD (adjusted relative RISKS = 1.0 and 1.6, respectively). When VPC characteristics such as frequency (2 or more uniform VPCs every 2 minutes) and complexity (multiforms, pairs, runs, R-on-T) were examined, those with frequent or complex VPCs were at a significantly increased risk of SCD (adjusted relative RISK = 4.2; p < 0.005), whereas for non-SCD no significant increase in risk was found (adjusted relative RISK = 1.6; P = 0.28). The data also suggest that the presence of frequent/ complex VPCs carries a greater risk for SCD in men younger than 50 years of age than in those 50 years or older.

The specificity of VPCs to SCD may bear an etiologic association and merits a careful evaluation of otherwise healthy men who demonstrate VPCs, particularly frequent/complex, on a short-term electrocardiographic recording.