Reduction of heart rate variability in hypertensive elderly

Figures & data

Table 1. Characterization of the sample.

	GroupMean (SD)
Variables	Control(n = 40)	Hypertension(n = 40)	p
Age (years)	67.03 (6.15)	68.38 (8.14)	0.430
Height (m)	1.66 (0.09)	1.64 (0.07)	0.370
Weight (kilograms)	74.31 (12.54)	77.38 (10.88)	0.270
BMI (Kg/m2)	26.84 (3.41)	28.60 (3.40)	0.300

Student t test for independent samples; Standard deviation (SD); Meters (m); Kilograms (kg); Body mass index (BMI); Healthy elderly (Control); Elderly hypertensive without the use of beta-blockers (Hypertension).

Figure 1. Mean RR interval (MeanRR) of the patients in the control and hypertension groups. The symbols represent each subject from each group. • Control group and ▴Hypertension group.

Figure 2. Standard deviation of the mean of all normal RR intervals (SDNN) of the patients in the control and hypertension groups. The symbols represent each subject from each group. • Control group and ▴Hypertension group.

Table 2. Comparison of Heart Rate Variability parameters in the time domain between the control group and the hypertension group.

Variables	Group				p	Cohen's	Effect Size
	Control (n = 40)		Hypertension (n = 40)
Mean (SD)	Median (p. 25–p. 75)	Mean (SD)	Median (p. 25–p. 75)
MeanRR (ms)	782.73 (112.78)	781.20 (687.35–900.13)	832.35 (104.46)	841.05 (767.70–913.18)	0.040^a	−0.45	Medium
SDNN (ms)	52.73 (18.05)	58.35 (34.05–67.70)	44.70 (16.36)	43.15 (32.40–55.70)	0.030^b	0.46	Medium
MeanHR (bmp)	77.24 (10.03)	77.49 (67.65–87.13)	72.69 (10.90)	71.48 (64.10–78.53)	0.034^b	0.43	Medium
RMSSD (ms)	23.61 (13.22)	19.65 (13.00–29.73)	21.49 (8.58)	20.60 (13.18–29.85)	0.950^b	0.19	Small
pNN50 (%)	3.32 (2.36)	2.55 (1.00–5.35)	2.80 (2.19)	1.45 (1.00–5.00)	0.198^b	0.23	Medium

a Student t test for independent samples;

b Mann-Whitney test; P-value / level of significance (p); Healthy Elderly (Control); Elderly hypertensive without the use of beta-blockers (Hypertension); Standard deviation (SD); Percentiles 25 e 75 (p. 25–p. 75); Mean RR interval (MeanRR); Millisecond (ms); Standard deviation of the mean of all normal RR intervals (SDNN); Mean of the RR intervals in the selected time interval (MeanHR); Beat per minute (bpm); Square root ousing of the squared mean of the differences between successive normal RR intervals (RMSSD); Percentage of adjacent RR intervals with duration difference greater than 50ms (pNN50); Percentage (%).

Figure 3. High frequency (HF), in control and hypertension groups. The symbols represent each subject from each group. • Control group and ▴Hypertension group.

Table 3. Comparison of Heart Rate Variability parameters in the frequency domain between the control group and the hypertension group.

Variables	Group				p	Cohen’s	Effect Size
	Control (n = 40)		Hypertension (n = 40)
	Mean (SD)	Median (p. 25–p. 75)	Mean (SD)	Median (p.25–p.75)
LF (ms^2)	235.52 (170.50)	154.00 (96.75–400.00)	233.69 (124.42)	213.50 (141.00–307.00)	0.480^a	0.01	Small
LF (nu)	69.11 (19.31)	71.75 (61.60–83.35)	61.64 (19.73)	66.90 (49.28–77.33)	0.071^a	0.38	Medium
HF (ms^2)	249.14 (131.29)	247.00 (142.00–350.00)	168.98 (73.94)	157.00 (112.00–206.25)	0.002^a	0.75	Medium
HF (nu)	30.64 (13.91)	30.70 (21.85–40.00)	32.38 (12.92)	33.10 (21.28–43.50)	0.390^a	−0.12	Small
LF/HF (-)	2.63 (1.32)	2.51 (1.62–3.59)	2.54 (1.57)	2.02 (1.00–3.90)	0.462^a	0.06	Small

a Mann-Whitney test;

p-value / level of significance (p); Healthy Elderly (Control); Elderly hypertensive without the use of beta-blockers (Hypertension); Standard deviation (SD); Percentiles 25 e 75 (p. 25–75); Millisecond (ms); Low frequency (LF); Millisecond squared (ms2); High frequency (HF); Standard unit (nu); Ratio between LF and HF (LF / HF).

Figure 4. Ratio between SD1 and SD2 of the patients in the control and hypertension groups. The symbols represent each subject from each group. • Control group and ▴Hypertension group.

Table 4. Comparison of the geometric indices of Heart Rate Variability between the control group and the hypertension group.

Variables	Group				p	Cohen’s	Effect size
	Control (n = 40)		Hypertension (n = 40)
	Mean (SD)	Median (p. 25–75)	Mean (SD)	Median (p. 25–75)
TINN (ms)	203.38 (80.26)	205.00 (133.75–261.25)	161.83 (53.25)	167.50 (120.00–199.25)	0.018^a	0.61	Medium
RRTri (-)	9.61 (3.50)	9.79 (6.95–12.00)	8.62 (2.53)	8.97 (6.48–10.36)	0.053^a	0.32	Medium
SD1 (ms)	14.44 (7.58)	13.20 (8.20–19.78)	14.31 (5.83)	14.30 (9.38–17.75)	0.585^b	0.02	Small
SD2 (ms)	67.07 (26.23)	71.95 (42.68–90.00)	57.37 (19.23)	59.40 (39.78–70.85)	0.051^b	0.42	Medium
SD1/SD2 (-)	0.22 (0.10)	0.22 (0.13–0.30)	4.09 (1.18)	3.91 (3.32–5.00)	0.001^a	−4.62	Small

a Student t test for independent samples;

b Mann-Whitney test; p-value/level of significance (p; Healthy Elderly (Control); Elderly hypertensive without the use of beta-blockers (Hypertension); Standard deviation (SD); Percentiles 25 e 75 (p. 25–75); Millisecond (ms); Millisecond (ms); Triangular interpolation of RR intervals (TINN); High frequency (HF); Standard unit (nu); Ratio between LF and HF (LF/HF); Standard deviation of instantaneous beat-to-beat variability (SD1); Long-term standard deviation of continuous R-R intervals (SD2); Ratio between SD1 and SD2 (SD1/SD2).