ABC | Volume 110, Nº4, April 2018

Original Article Silva et al Postural hypotension: spectral analysis Arq Bras Cardiol. 2018; 110(4):303-311 Table 1 – Anthropometric and clinical variables of studied patients Variables Median Interquartile range Q1 - Q3 Minimum value Maximum value Age (years) 73.0 65.5 – 77.0 60.0 91.0 Weight (kg) 62.0 56.0 – 72.0 44.0 102.0 Height (m) 1.58 1.51 – 1.62 1.41 1.80 BMI (kg/m 2 ) 25.7 22.5 – 29.7 17.8 40.9 WC (cm) 87.3 80.3 – 96.0 68 116 HR supine position (bpm) 68.0 60.0 – 76.0 38.0 105.0 HR orthostatic (bpm) 72.0 64.0 – 80.0 44.0 109.0 SAP supine position (mmHg) 140.0 127.0 – 152.0 92.0 196.0 DAP supine position (mmHg) 80.0 75.0 – 87.0 60.0 104.0 SAP orthostatic position (mmHg) 130.0 120.0 – 142.0 60.0 220.0 DAP orthostatic position (mmHg) 80.0 70.0 – 90.0 30.0 100.0 SAP seated position (mmHg) 135.0 120.0 – 150.0 100.0 194.0 DAP seated position (mmHg) 80.0 70.0 – 90.0 60.0 106.0 BMI: body mass index; WC: waist circumference; HR: heart rate; bpm: beats per minute; SAP: systolic arterial pressure; DAP: diastolic arterial pressure; mmHg: millimeter of mercury; Q1: 25 th percentile; Q3: 75 th percentile Table 2 – Between-group comparison of heart rate, blood pressure and cardiovascular risk scores Variables Case group Median (Q1 – Q3) Control group Median (Q1 – Q3) p-value HR supine position (bpm) 62.0 (57.0 – 72.0) 69.0 (63.5 – 76.0) 0.001 HR orthostatism (bpm) 67.0 (60.0 – 76.0) 75.0 (68.0 – 80.0) 0.006 SAP supine position (mmHg) 140.0 (130.0 – 160.0) 135.0 (125.8 – 150.0) 0.189 DAP supine position (mmHg) 80.0 (70.0 – 90.00 80.0 (78.0 – 86.0) 0.543 SAP orthostatism (mmHg) 120.0 (110.0 – 135.0) 136.5 (120.0 – 146.2) 0.001 DAP orthostatism (mmHg) 72.0 (60.0 – 84.0) 80.0 (77.3 – 90.0) 0.001 Framingham score 15.5 (6.0 – 24.3) 12.0 (6.0 – 17.0) 0.063 PROCAM score 10.6 (5.01 – 21.4) 11.0 (5.0 – 16.8) 0.537 SD: standard deviation; HR: heart rate; bpm: beats per minute; SAP: systolic arterial pressure; DAP: diastolic arterial pressure; mmHg: millimeter of mercury. Mann‑Whitney test; Q1: 25 th percentile; Q3: 75 th percentile in the frequency of diabetes (7 patients in the case group and 11 in the control group; p = 0.86) or coronary arterial disease (5% in the case group and 9% in the control group) between the groups. All patients were stable, without chest pain. Regarding the main groups of antihypertensives, higher percentage of users of ACE inhibitors was observed in the case group (41.0%) than in the control group (21.2%) (p = 0.030). No difference was found in other antihypertensive agents. Heart rate variability Medians and interquartile ranges of HRV components in supine position were – LF 233.0 ms 2 (130.5 – 422.5), HF 133.0 ms 2 (62.0 – 347.5), LF/HF 1.6 (0.8 – 3.0) – and in orthostatic position were – LF 218.0 ms 2 (110.5 – 359.7), HF 76.0 ms 2 (32.0 – 227.0) and LF/HF 2.1 (1.1 e 4.8). Comparisons of HRV components between supine and orthostatic positions performed by the Wilcoxon test showed no difference in LF (p = 0.080), but significant differences in HF (p = 0.01) and LF/HF (p < 0.001). When HRV absolute values were compared between case and control groups by the Mann-Whitney test, significant difference was found in LF in supine position (Table 3). No difference between the groups was found in other components. Due to HRV data interval, a logarithmic transformation of HRV components was performed, and the same p-values were maintained. For analysis of HRV with change of position, median differences in LF component were compared between case and control groups (i.e. between the supine and the orthostatic position, median -0.27 ms 2 ) by the Mann Whitney test (p = 0.43). Median differences of HF and LF/HF components were 33.0 ms 2 and 0.53, respectively, and p-values of respective comparisons were 0.74 and 0.94. 305