Ventricular Ectopy as a Predictor of Heart Failure and Death

Abstract

Background: Studies of patients presenting for catheter ablation suggest that premature ventricular contractions (PVCs) are a modifiable risk factor for congestive heart failure (CHF). The relationship among PVC frequency, incident CHF, and mortality in the general population remains unknown.

Objectives: The goal of this study was to determine whether PVC frequency ascertained using a 24-h Holter monitor is a predictor of a decrease in the left ventricular ejection fraction (LVEF), incident CHF, and death in a population-based cohort.

Methods: We studied 1,139 Cardiovascular Health Study (CHS) participants who were randomly assigned to 24-h ambulatory electrocardiography (Holter) monitoring and who had a normal LVEF and no history of CHF. PVC frequency was quantified using Holter studies, and LVEF was measured from baseline and 5-year echocardiograms. Participants were followed for incident CHF and death.

Results: Those in the upper quartile versus the lowest quartile of PVC frequency had a multivariable-adjusted, 3-fold greater odds of a 5-year decrease in LVEF (odds ratio [OR]: 3.10; 95% confidence interval [CI]: 1.42 to 6.77; p = 0.005), a 48% increased risk of incident CHF (HR: 1.48; 95% CI: 1.08 to 2.04; p = 0.02), and a 31% increased risk of death (HR: 1.31; 95% CI: 1.06 to 1.63; p = 0.01) during a median follow-up of >13 years. Similar statistically significant results were observed for PVCs analyzed as a continuous variable. The specificity for the 15-year risk of CHF exceeded 90% when PVCs included at least 0.7% of ventricular beats. The population-level risk for incident CHF attributed to PVCs was 8.1% (95% CI: 1.2% to 14.9%).

Conclusions: In a population-based sample, a higher frequency of PVCs was associated with a decrease in LVEF, an increase in incident CHF, and increased mortality. Because of the capacity to prevent PVCs through medical or ablation therapy, PVCs may represent a modifiable risk factor for CHF and death.

Keywords: arrhythmia; mortality; premature ventricular contractions.

Figure 1. Rates of CHF and All-Cause Mortality by PVC Quartiles

Unadjusted Kaplan-Meier estimates depicting incident congestive heart failure and mortaility, as stratified by percent PVC count quartiles. Quartiles 1 through 4 represent PVC burdens of 0% to 0.002%, 0.002% to 0.011%, 0.011% to 0.123%, and 0.123% to 17.7%, respectively. CHF = congestive heart failure; PVC = premature ventricular contraction.

Figure 2. Test Characteristics of PVCs for 15-year CHF Risk

The predicted 15-year risk for CHF (using the log base 2-transformed PVC model) is plotted against the percentage of PVCs. The PPV, NPV, sensitivity and specificity for the diagnosis of CHF at 15 years for an individual participant are listed for various unadjusted PVC cutoff values. NPV = negative predictive value; PPV = positive predictive value. Other abbreviations as in Figure 1.

Figure 3. Population-Attributable Risk of PVCs for Incident CHF

Each bar represents the population-attributable risk for the listed covariates, with error bars denoting 95% CIs. BMI = body mass index (weight in kg divided by the square of the height in meters); CAD = coronary artery disease. Other abbreviations as in Figure 1.

Central Illustration. Associations between Baseline Percent PVCs and 5-year Reduction in LVEF, Incident CHF, and Mortality

Squares represent unadjusted (red) and adjusted (blue) ORs for log base 2-transformed percent PVCs as a predictor of any reduction in qualitative LVEF between the baseline and 5-year echocardiograms or HRs for incident CHF and mortality. Multivariable models included adjustment for age, sex, race, body mass index, and a history of hypertension, diabetes, coronary artery disease, beta-blocker use, Holter-based AF, and number of Holter-based ventricular tachycardia episodes. Error bars indicate 95% CIs. Hazard ratios express the increase in risk per doubling of the percent PVCs. CHF = congestive heart failure; CI = confidence interval; HR = hazard ratio; LVEF = left ventricular ejection fraction; OR = odds ratio; PVC = premature ventricular contraction.