Prognostic grading and significance of ventricular premature beats after recovery from myocardial infarction.

A 6-hour taped electrocardiogram recording was obtained prior to hospital discharge on 193 patients less than 66 years of age with a definite or probable myocardial infarction. All ventricular premature beats (VPBs) were identified on the 6-hour recording, and the various VPB characteristics were related to a complicated course (CC) defined as cardiac death or myocardial reinfarction within 4 months after hospital discharge. Only three univariate VPB characteristics (multiform pattern, bigeminal rhythm, and frequency greater than or equal to 20/hr) were significantly associated with a 4-month posthospital CC. By use of bivariate and multivariate combinations of these three VPB characteristics, a two-grade prognostic stratification system was derived: Grade I VPBs (CC = 8%) included patients with less than 20 VPB/hr but with neither multiform nor bigeminal beats: Grade II VPBs (CC = 31%, P less than 0.001) contained patients with greater than or equal to 20 VPBs/hr or with multiform or bigeminal beats or both. Patients with Grade II VPBs had more severe cardiac disease, but when patients were stratified by the clinical severity of their cardiac disease, Grade II VPBs identified patients with higher CC rates. The clinical significance of these findings together with a critical analysis of the prognostic stratification method are discussed.