Impact of premature ventricular complex burden and morphology on long-term survival in patients without structural heart disease

Background

Premature ventricular complexes (PVCs) are common and can occur in patients both with and without structural heart disease (SHD). In general PVC populations, a high PVC burden and non-right ventricular outflow tract (RVOT) morphologies are considered predictors of adverse outcomes. However, the impact of these factors on long-term survival in patients without SHD is not as clear.

Aim

To evaluate the impact of PVC burden and morphology on the long-term survival in PVC patients without SHD.

Methods

We conducted a retrospective cohort study in which we included patients who received a PVC diagnosis between 2010 and 2016. All patients had undergone at least echocardiography and an exercise stress test without signs of structural abnormalities, and patients with a prior history of SHD were excluded. PVC burden was assessed using at least 24-hour Holter monitoring and analysed as both a continuous variable (per 1000 PVCs/day) and a categorical variable (<1000, 1000-5000, 5000-10,000, and >10,000 PVCs/day). PVC morphology was classified as RVOT or non-RVOT based on 12-lead ECG. The primary outcome was all-cause mortality. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals, adjusted for age, sex, hypertension, and atrial fibrillation. PVC burden was also analysed using a restricted cubic spline model to evaluate a potential non-linear relationship.

Results

A total of 699 patients were included in the PVC burden analyses (56 deaths) and 515 in the morphology analyses (47 deaths), with a median follow-up of 10 years (IQR 8-11 years).

There was no statistically significant association between PVC burden and all-cause mortality, neither as a continuous variable (HR 1.01, 95% CI 0.98–1.04) nor as a categorical variable (for >10,000 vs. <1000 PVCs/day: HR 1.26, 95% CI 0.57–2.77). Restricted cubic spline analysis did not show evidence of a non-linear relationship (p = 0.28).

RVOT morphology was associated with lower all-cause mortality compared to non-RVOT morphology in the univariable analysis (HR 0.33, 95% CI 0.15–0.73), but the difference did not meet statistical significance after multivariable adjustment (adjusted HR 0.55, 95% CI 0.24–1.22).

No significant interaction between PVC burden and morphology was observed. Results were robust in sensitivity analyses using extended covariate adjustments as well as when adjusting for symptoms.

Conclusions

In PVC patients who had undergone at least echocardiography and an exercise stress test to rule out SHD, neither PVC burden nor morphology was independently associated with long-term all-cause mortality. The results highlight the need for risk assessment strategies beyond these traditional risk factors.Adjusted restricted cubic spline analysis.Multivariable Cox regression analysis.