USE OF SPECTRAL-ANALYSIS OF BLOOD-PRESSUR E VARIABILITY IN HYPERTENSIVE SUBJECTS WITH LEFT-VENTRICULAR HYPERTROPHY

Objective : To study the relationship between spectral analysis measur ement of blood pressure (BP) and heart rate (HR) at rest, in untreated essential hypertension, and their relationship with the development o f left ventricular hypertrophy (LVH). Design and methods : 41 untreate d hypertensives (25M/16W, age 50 +/- 12, range 23-73) were measured at rest (WHO criteria DBP > 90 mmHg) by digital continuous photoplethysm ography (Finapres 2300 (F), 6 mn of measurement in the dorsal decubitu s position and standing up). Measurement of LVH (Devereux criteria, le ft ventricular mass index LVMI, g/m2) to analyse two groups (LVMI+: LV MI > 107 if women and 120 if men ; n = 19 ; LVMI = 137 +/- 25), and (L VMI-; n = 22 ; LVMI = 92 +/- 17). The overall variability is standard deviation (SD), spectral analysis variability (SA) is FFT of 256 point s over 3 periods low (LF: 0.004-0.07Hz), medium (MF: 0.07-0.13Hz), hig h (HF: 0.13-0.5Hz). Comparisons by Wilcoxon test and Anova (age, sex) ( p < 0.05, ** p < 0.01). Results : By WHO criteria, the SBP was sign ificantly lower in the LVMI-group (153 +/- 10 vs 165 +/- 18*), the DB P was not significantly different (94 +/- 6 vs 96 +/- 10). By continuo us measure (F) at rest there was no significant difference for SBP or DBP. On standing up the SBP was significantly lower in the LVMI-group (148 +/- 20 vs 162 +/- 22*). The SD of the DBP at rest was more eleva ted in the LVMI-group (3.34 vs 3.06), but not significantly different standing up. There was no significant difference in SBP at rest (6.7 vs 6.32) or standing (9.13 vs 11.5). The Spectral analysis of the MF w as significantly elevated in the LVMI-group at rest for SBP (3.56 vs 3 .01), DBP (1.99 vs 1.19*), and HR (1.79 vs 1.77*). This was not signi ficantly different in the LF and HF for SBP, DBP, HR. Conclusion: Thes e results are different from those obtained by invasive ambulatory mea sures. The spontaneous variability in BP and HR at rest is increased w hen there is no cardiac effect (LVMI-). SA gives additional informatio n in showing that the increase in variability is due to an increase in the Mayer waves, suggesting the existence of an elevation in adrenerg ic tone in hypertensive patients not having LVH.