The Prevalence and Prognostic Value of Rest Premature Ventricular Contractions

This chapter discusses research conducted to evaluate the prognostic significance of premature ventricular contractions (PVCs) on a routine electrocardiogram (ECG), and to evaluate their relationship to heart rate, heart failure and sport participation. Identifying parameters to help risk stratify patients and provide prognostic implications can help identify individuals who may benefit from early diagnosis and intervention. Our discussion utilizes research from a large database of computerized 12-lead ECGs, including 45,402 members of the US Veterans Administration, of which 352 were known to have heart failure. In addition, 750 athletes were analyzed. Echocardiograms and treadmill tests were performed on all those with heart failure and echocardiograms were part of the annual physical exam of the college athletes. Briefly, there were 1731 patients with PVCs (3.8%) in the total veteran population. Twentynine of the 352 with heart failure exhibited a PVC (8%) and 5 of the 750 athletes exhibited a PVC (0.7%). Compared to patients without PVCs, those with PVCs had significantly higher all-cause (39% vs. 22%, p<0.001) and cardiovascular mortality (20% vs. 8%, p<0.001). PVCs remain a significant predictor even after adjustment for age and other ECG abnormalities. The presence of multiple PVCs or complex morphologies did not add significant additional prognostic information. Those patients with PVCs had a significantly higher heart rate than those without PVCs (meanSD: 78.615 vs. 73.516 bpm, p<0.001). When patients were divided into groups by heart rate (<60, 60-79, 80-99 and >100 bpm) and by the presence or absence of PVCs, mortality increased progressively with heart rate and doubled with the presence of PVCs. Using regression analysis, heart rate was demonstrated to be an independent and significant predictor of PVCs. We identified 352 patients (64 ± 11 years; 7 females) with a history of clinical HF undergoing treadmill testing for clinical reasons at the VAPAHCS (1987-2007). Patients with rest PVCs were defined as having ≥1 PVC on the ECG prior to testing (n=29; 8%).During a median follow-up period of 6.2 years, there were 178 deaths of which 76 (42.6%) were due to CV causes. At baseline, compared to patients without rest PVCs, those with rest PVCs had a lower ejection fraction (EF) (30% vs. 45%) and the prevalence of EF≤35% was higher (75% vs. 41%). They were more likely to have smoked (76% vs. 55%).The all-cause and CV mortality rates were significantly higher in the rest PVCs group (72% vs. 49%, p=0.01 and 45% vs. 20%, p=0.002; respectively). After adjusting for age, beta-blocker use, rest ECG findings, resting heart rate (HR), EF, maximal systolic blood pressure, peak HR and exercise capacity,