Premium
Baroreflex unloading blunts chemoreceptor sensitivity in Postural Tachycardia Syndrome (POTS)
Author(s) -
Taneja Indu,
Clarke Debbie A.,
Medow Marvin S.,
Ocon Anthony J.,
Stewart Julian M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1026.17
Subject(s) - hypercapnia , supine position , hyperoxia , anesthesia , baroreflex , hypoxia (environmental) , peripheral chemoreceptors , chemoreceptor , heart rate , medicine , respiration , oxygenation , blood pressure , oxygen , cardiology , chemistry , anatomy , lung , acidosis , receptor , organic chemistry
POTS have increased minute ventilation (V E ) and decreased end tidal carbon dioxide (ETCO 2 ) compared to healthy subjects. Chemoreceptor sensitivity was measured in 18 POTS (14F, 4M), 10 healthy controls (6F, 4M) 16–35 years old by exposing them to eucapneic hyperoxia‐30%oxygen, eucapneic hypoxia (10%oxygen) and hypercapnia 30%oxygen+5%carbon dioxide) in supine and HUT70 position. We measured heart Rate (HR), mean arterial pressure (MAP) oxygen saturation, ETCO2, mean cerebral blood flow velocity (mCFV) and V E . Chemoreflex sensitivity was ascertained by comparing slopes determined from eucapneic hypoxia‐hyperoxia to measure peripheral chemoreflex sensitivity, and hyperoxic hypercapnia –eucapnia to measure central chemoreflex sensitivity. POTS had significantly higher resting HR, lower MAP, stroke volume (SV) and mCFV as compared to controls (p<0.05). Hypoxia and hypercapnia increased the HR, MAP, CO, mCFV and V E (p<0.05). POTS had increases in V E during supine hypoxia (POTS vs. controls, 3.6± 0.9 vs. 1.6± 0.2, p=0.003) which reversed in HUT70 (1.96± 0.3 vs. 5.4± 1.2). In both POTS and controls, hypercapnia resulted in similar increases in V E when supine but no further increases when HUT70. POTS have higher peripheral chemoreflex sensitivity than controls which attenuates during unloading of baroreflexes.