Prevalence and heart rate variability characteristics of premature ventricular contractions detected by 24-hour Holter among outpatients with palpitations in China: a cross-sectional study

OBJECTIVE: To analyse the prevalence and heart rate variability (HRV) characteristics of premature ventricular contraction (PVC) detected by 24-hour Holter among Chinese outpatients with palpitations. DESIGN: A cross-sectional study. SETTING: This study was conducted in a tertiary hospital. PARTICIPANTS: A total of 4754 outpatients who received 24-hour Holter for palpitations. MAIN OUTCOME MEASURES: Prevalence, HRV time-domain and frequency-domain analyses of 24-hour Holter, and echocardiographic parameters were assessed. Propensity score matching (PSM) was applied to balance baseline variables (age, gender) to decrease the bias between comparison groups. RESULTS: The prevalence of PVC was 67.7% (3220/4754), and was higher in men than women (69.9% vs 66.0%, p=0.004); the prevalence of frequent PVCs (PVC burden≥5%) was 7.7% (368/4754). Older patients had the highest frequency of PVC among all patients. However, among 3220 patients with PVC, younger patients’ PVC burden was much higher. Matched 1:1 by age and gender, the HRV time-domain parameters in patients with PVC were all lower than those in patients without PVC (all p<0.05); for the HRV frequency-domain parameters, the patients with frequent PVCs had a higher low frequency/high frequency (LF/HF) ratio (5.4 vs 2.8, p<0.001) than those with PVC burden less than 5%. CONCLUSIONS: The prevalence of PVC and frequent PVCs were 67.7% and 7.7%, respectively, detected by 24-hour Holter among Chinese outpatients with palpitations. Decreased HRV time-domain parameters suggested the occurrence of PVC, and increased LF/HF ratio represented the imbalance of autonomic nervous system in patients with frequent PVCs. Further studies are needed to understand the HRV indexes in PVC patients.