RESUMO
BACKGROUND: beat-to-beat technology is increasingly used for investigating orthostatic intolerance (OI) but the prevalence of orthostatic hypotension (OH) diagnosed with this technology is unclear. OBJECTIVES: (i) to use beat-to-beat technology to define the prevalence of OH, (ii) to investigate the pathological correlates of OH, (iii) to report the diversity of postural BP responses. METHODS: cross-sectional study of adults ≥ 65 years. BP responses to a 3-min head-up tilt were analysed. RESULTS: of 326 participants, 203(62.3%) were females. The median (IQR) age was 73 (70-78). One hundred and ninety-one (58.6%) met standard (20 mmHg systolic/10 mmHg diastolic) criteria for OH. The prevalence was higher in females (60.1% F versus 56.1% M); 47% were arteriolar subtype, 33% were venular, 9% were mixed and 11.0% could not be classified. Morphological analysis identified 102 subjects with 'small drop, overshoot', 131 with 'medium drop, slow recovery' and 31 with 'large drop, nonrecovery'. Those with OH had a lower BMI (P = 0.02), a higher resting heart rate (P = 0.005), were more likely to take a psychotropic (P = 0.02), have vertigo (P = 0.004) and report OI (P = 0.02). The 95th centile for the duration of systolic BP (SYSBP) decay >20 mmHg was 175 s and the slope of systolic BP decay was 4.75 mmHg/s. The 5th centile for percentage recovery of SYSBP was 81.4%. CONCLUSION: (i) beat-to-beat methods identify a higher prevalence of OH than sphygmomanometry, (ii) the pathological correlates of OH diagnosed in this manner are similar to those described for sphygmomanometry, (iii) there is a diverse pattern of orthostatic BP decay that could be used in future research to predict adverse outcomes in OH.
