The prognostic significance of frequency and morphology of premature ventricular complexes during ambulatory Holter monitoring

Background Multiform premature ventricular complexes (PVCs) are associated with an adverse prognosis in patients with structural heart disease. Very frequent PVCs are associated with ventricular dysfunction. Our hypothesis is that multiform PVCs confer an adverse prognosis in the general population. Methods We performed a retrospective cohort study of patients ≥18 years old referred to our institution for 24-hour ambulatory Holter monitoring between July 1, 2008 and December 31, 2009. Holters without PVCs or with more frequent ectopy (couplets, triplets, or nonsustained ventricular tachycardia) were excluded. Clinical and adverse event (AE) data ("major adverse cardiovascular event" or new/worsening heart failure) were gathered from chart review. Data was analyzed by PVC frequency (rare, occasional, or frequent) and pattern (uniform or multiform). Results A total of 222 patients (43% male, mean age: 55 ± 16 years) were evaluated (median follow-up 2.3 years [IQR: 2.0-2.6]). Median frequency was 2 PVCs per hour (IQR: 1-13). Multiform PVCs were noted in 48%. Patients with multiform PVCs were older, and had a higher prevalence of comorbidities. Thirty-nine AE were noted. Patients with an AE were younger, had a higher prevalence of HTN, diabetes, CAD, CHF, and previous MI. The multiform group had a higher incidence of AE (28%) compared to the uniform group (8%) (P < 0.001). Increasing PVC frequency was associated with a higher incidence of AE (8% vs 24% vs 35%, respectively). In Cox regression analyses, the multiform pattern but not frequency predicted AE. Conclusions Multiform PVCs were associated with a 4-fold increase in AE in patients referred for ambulatory Holter monitoring.