Age-related reference intervals for ambulatory electrocardiographic parameters in healthy individuals

Figure 1. Diurnal variation in the median number of bradyarrhythmias. Significant night-time dominance was observed in the diurnal variation of the median number of sinus pauses (P = 0.002) (A). Significant night-time dominance in the diurnal variation of the median number of atrio-ventricular blocks (P = 0.009) (B). Comparisons of frequencies among each hour in sinus pause and AV block were performed using the Kruskal–Wallis test. AV block: atrio-ventricular block.

Figure 2. Diurnal variation in the median frequency of ventricular and supraventricular ectopy. A significant diurnal variation was observed in the mean frequency of VE (P < 0.001). The daytime prevalence of VE was predominant, which was parallel to the diurnal variation in HR (A). Meanwhile, the mean frequency of SVE was significantly higher at 4:00 and during 13:00–15:00 (P < 0.001). However, the diurnal variation of SVE was not parallel to the diurnal variation of HR (B). Comparisons of frequencies among each hour in VE and SVE were performed using the Kruskal–Wallis test. HR: heart rate, SVE: supraventricular ectopy, VE: ventricular ectopy.

Figure 3. Changes in the ectopy prevalence and parameters influencing ectopy prevalence in each generation. The log VE/day and log SVE/day were significantly decreased in the older generation (P = 0.014 for log VE; P < 0.001 for log SVE), (A), (B). On the other hand, body mass index was significantly higher in the 40–59-year age group than in the 20–39- and 60–89-year age groups (P = 0.016) (C). HRV parameters (log SDNN, log RMSSD, and log HFnu), which influenced the prevalence of SVE, were significantly decreased in the older generation (P < 0.001 for all, respectively) (D–F). The parameters influencing the ectopy prevalence in each generation were compared using the Kruskal–Wallis test; post hoc multiple comparisons were performed using the Bonferroni method. HRV, heart rate variability; SVE, supraventricular ectopy; VE, ventricular ectopy.