ABSTRACT
Objective To compare the Cosine and Dip methods in describing the rhythm of blood pressure(BP).Methods The BP was measured with non-traumatic ambulatory blood pressure monitoring(ABPM) for 24 h and analyzed with Cosine and Dip methods.The characters of the circadian rhythm of BP were studied and two methods were compared.Results The ratios of mesor and amplitude(A/M) of systolic blood pressure(SBP) and diastolic blood pressure(DBP) were(7.78?0.42)% and(7.98?0.39)%,respectively.The majority of acrophases of BP was on daytime,especially between 10∶00 am and 3∶00 pm.The amplitudes of acrophase in different periods analyzed with Cosine method were not significantly different each other,whereas analyzed with Dip method to be significant difference.Conclusion There is difference between Cosine and Dip methods in describing the rhythm of BP,since rhythms of acrophases of some cases were inaccurately described with Dip method.