Baroreflex function during 45-degree passive head-up tilt before and after long-term thiazide therapy in the elderly with systolic systemic hypertension
| Autor: | Kishan G. Mehrotra, Saktipada Mookherjee, Norma E. Hill, Suman Vardan, Harold Smulyan |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Time Factors Supine position Systole medicine.medical_treatment Posture Diastole Baroreflex Hydrochlorothiazide Internal medicine medicine Humans Thiazide Aged Cardiac cycle business.industry Hypertension Cardiology Diuretic Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | The American Journal of Cardiology. 73:253-257 |
| ISSN: | 0002-9149 |
| DOI: | 10.1016/0002-9149(94)90229-1 |
| Popis: | The ratio of the 30th to the 15th cardiac cycle duration on an electrocardiogram (30:15 ratio) immediately after active standing from the supine position has been used as one of the markers of baroreflex function. A ratio ofor = 1.0 has been suggested to indicate baroreflex dysfunction. Blood pressure (BP) changes were measured and the 30:15 ratio was calculated after standing and during 45-degree passive head-up tilt from the supine position in 10 nondiabetic men (mean age +/- SE 70.1 +/- 1.05 years, and BP150/90 mm Hg). After tilt the decrease in systolic BP (from 132 +/- 4.8 to 117 +/- 6.3 mm Hg; p0.001) appeared to be larger than that after standing (from 132 +/- 4.6 to 123 +/- 5.8 mm Hg; p0.01), whereas the 30:15 ratios were 0.965 +/- 0.006 and 0.970 +/- 0.014, respectively, which suggested baroreflex dysfunction. Although the mean of the 2 ratios did not differ, the variance appeared to be less during tilting than after standing. Thus, the 45-degree passive head-up tilt appeared to be a better and more uniform inducer of orthostatic stress than active standing. Therefore, 45-degree head-up tilt was used in a group of 10 nondiabetic male patients (aged 70 +/- 1.46 years) with isolated systolic hypertension (systolic BP160 mm Hg, diastolic BP of90 mm Hg) to assess their baroreflex function. Upon tilting, their systolic BP decreased from 190 +/- 5.5 to 179 +/- 5.8 mm Hg (p0.05) and their 30:15 ratio was 0.985 +/- 0.011.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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