SDANNStandard Deviation of the Averages of NN (Normal Sinus to Normal Sinus) Intervals in All 5-Minute Segments of a 24-Hour Recording (cardiology)
SDANNSelf Developing Artificial Neural Network
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SDANN gives information on variation for prolonged period.
Spearman correlation analysis of the hypertensive patients showed that LF and LF/HF were negatively correlated with TO, while SDNN, SDANN, rMSSD, PNN50, VLF, LF, and HF were positively correlated with TS (Table 5).
Heart rate variability was measured as time domains measured over 24 hours (SDNN, ASDNN, rMSSD, pNN50%, SDANN, and mean NN) and frequency domains measured hourly (very low frequency (VLF), low frequency (LF), high frequency (HF), and low/high ratio) as well as a mean value taken over the 24-hour monitoring period.
Five time-domain indices were measured: the standard deviation of all normal-to-normal RR intervals in the entire recording (SDNN); the mean of the standard deviations of the normal RR intervals in all 5-min segments in the entire 24-h recording (SDNN index); and the mean of the standard deviation of the averaged normal-to-normal RR intervals in all 5-min segments of the 24-h recording (SDANN index) represent the autonomic function; the root mean square of successive differences normal RR intervals and the percent of the differences between the adjacent normal-to-normal intervals >50 ms (pNN50), both of them are considered as a maker of parasympathetic tone.
Correlation coefficients for the linear regression between subgroups of ventricular arrhythmia complexity and SDNN, SDANN, SDNNIDX, rMSSD and pNN50 were [r.sup.2]<0.01 and P=0.99; [r.sup.2]<0.01 and P=0.86; [r.sup.2]<0.01 and P=0.85; [r.sup.2]=0.03 and P=0.53; and [r.sup.2]<0.01 and P=0.92, respectively.
Effects on time domain analysis: As shown in Table 3 and 4, the time domain analysis for the HW litters got higher results than for the LW litters, but the differences in SDANN and RMSSD were not significant.
Notes: CI, confidence interval; DBP, diastolic blood pressure; ET-1, endothelin-1; HF, high frequency; LF, low frequency; LF/HF, the ratio of LF to HF; pNN50, percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval; rMSSD, the root mean square of the successive differences; SBP, systolic blood pressure; SDANN, the standard deviation of the average NN intervals calculated over short periods; SDNN, the standard deviation of the normal-to-normal interval; VCAM-1, vascular cell adhesion molecule-1; VLF, very low frequency; vWF, von Willebrand factor.
Results: The SDNN, SDANN, rMSSD, PNN50 and HF parameters significantly increased compared with the conventional treatment group (all P less than 0.05).
Same pattern, but with smaller differences, was found in the case of SDANN on working days and resting days.
Os primeiros autores tambem observaram aumento das variaveis RMSSD, SDANN e de potencia de LF, sugerindo que a mudanca na VFC ocorreu em funcao do aumento da amplitude da arritmia sinusal respiratoria.
The following time-domain parameters where calculated: (1) RR intervals (representing the average heart rate), (2) standard deviation of normalized RR intervals (SDNN--representing the total variability), (3) standard deviation of 5-minute segments of normalized RR intervals (SDANN), (4) root mean square of the differences between successive normalized RR intervals (RMSSD--primarily representing the parasympathetic activity), and (5) the percentage of normalized RR intervals that differ more than 50% compared to the previous ones (pNN50--representing the parasympathetic dominance over the sympathetic activity) [22].