Filtered QRS duration exhibits a significant circadian rhythm in healthy subjects, increasing at night, and is strongly correlated with heart rate (r = 0.95, p < 0.001) and autonomic tone.
Observational (n=20)
In healthy subjects, filtered QRS duration exhibits a significant circadian rhythm that correlates closely with markers of autonomic tone.
Effect estimate: r = 0.95
p-value: p=<0.001
OBJECTIVE: To examine the circadian variation in the signal averaged electrocardiogram (saECG) and heart rate variability and investigate their relations in healthy subjects. METHODS: 24 hour ECGs were obtained with a three channel recorder using bipolar X, Y, and Z leads in 20 healthy subjects. The following variables were determined hourly: heart rate, filtered QRS (f-QRS) duration, low and high frequency components of heart rate variability (LF and HF), and the LF/HF ratio. RESULTS: Heart rate, f-QRS duration, HF, and the LF/HF ratio showed significant circadian rhythms, as determined by the single cosinor method. Heart rate and the LF/HF ratio increased during daytime, and f-QRS duration and HF increased at night. f-QRS duration was negatively correlated with heart rate (r = 0.95, p < 0.001) and the LF/HF ratio (r = 0.94, p < 0.001) and positively with HF (r = 0.93, p < 0.001). CONCLUSIONS: f-QRS duration has a significant circadian rhythm in healthy subjects and is closely related to the circadian rhythm of autonomic tone.
Nakagawa et al. (Fri,) conducted a observational in Healthy subjects (n=20). 24 hour ECG monitoring was evaluated on Correlation between filtered QRS (f-QRS) duration and heart rate (r = 0.95, p=<0.001). Filtered QRS duration exhibits a significant circadian rhythm in healthy subjects, increasing at night, and is strongly correlated with heart rate (r = 0.95, p < 0.001) and autonomic tone.