scholarly journals Reduced body mass index is associated with increased angiotensin II in young women with postural tachycardia syndrome

2007 ◽  
Vol 113 (11) ◽  
pp. 449-457 ◽  
Author(s):  
Julian M. Stewart ◽  
Indu Taneja ◽  
Marvin S. Medow
Keyword(s):  
Body Mass Index ◽  
Blood Flow ◽  
Cardiac Output ◽  
Angiotensin Ii ◽  
Body Mass ◽  
Peripheral Blood ◽  
Postural Tachycardia Syndrome ◽  
Peripheral Blood Flow ◽  
Reduced Body ◽  
Postural Tachycardia

Altered peripheral haemodynamics, decreased cardiac output, decreased blood volume and increased AngII (angiotensin II) have been reported in POTS (postural tachycardia syndrome). Recent findings indicate that BMI (body mass index) may be reduced. In the present study, we investigated the hypothesis that reduced BMI is associated with haemodynamic abnormalities in POTS and that this is related to AngII. We studied 52 patients with POTS, aged 14–29 years, compared with 36 control subjects, aged 14–27 years. BMI was not significantly reduced on average in the POTS patients, but was reduced in patients with decreased peripheral blood flow. POTS patients were then subdivided on the basis of BMI, and supine haemodynamics were measured. There was no difference in blood volume or cardiac output once BMI or body mass were accounted for. When POTS patients with BMI <50th percentile were compared with controls, calf blood flow [1.63±0.31 compared with 3.58±0.67 ml−1·min−1·(100 ml of tissue)−1] and maximum venous capacity (3.87±0.32 compared with 4.98±0.36 ml/100 ml of tissue) were decreased, whereas arterial resistance [56±0.5 compared with 30±4 mmHg·ml−1·min−1·(100 ml of tissue)−1] and venous resistance [1.23±0.17 compared with 0.79±0.11 mmHg·ml−1·min−1·(100 ml of tissue)−1] were increased. Similar findings were also observed when POTS patients with BMI <50th percentile were compared with POTS patients with BMI >50th percentile. There was no relationship between blood flow, resistance or maximum venous capacity with BMI in control subjects. BMI was inversely related to plasma AngII concentrations in those POTS patients with decreased peripheral blood flow, consistent with cachectic properties of the octapeptide. Patients with low-flow POTS had decreased body mass, but decreased body mass alone cannot account for findings of peripheral vasoconstriction. In conclusion, the findings suggest that reduced body mass relates to increased plasma AngII.

scholarly journals Increased plasma angiotensin II in postural tachycardia syndrome (POTS) is related to reduced blood flow and blood volume

2006 ◽  
Vol 110 (2) ◽  
pp. 255-263 ◽  
Author(s):  
Julian M. Stewart ◽  
June L. Glover ◽  
Marvin S. Medow
Keyword(s):  
Blood Flow ◽  
Angiotensin Ii ◽  
Blood Volume ◽  
High Flow ◽  
The Other ◽  
Low Flow ◽  
Postural Tachycardia Syndrome ◽  
Peripheral Blood Flow ◽  
Ang Ii ◽  
Postural Tachycardia

POTS (postural tachycardia syndrome) is associated with low blood volume and reduced renin and aldosterone; however, the role of Ang (angiotensin) II has not been investigated. Previous studies have suggested that a subset of POTS patients with increased vasoconstriction related to decreased bioavailable NO (nitric oxide) have decreased blood volume. Ang II reduces bioavailable NO and is integral to the renin–Ang system. Thus, in the present study, we investigated the relationship between blood volume, Ang II, renin, aldosterone and peripheral blood flow in POTS patients. POTS was diagnosed by 70° upright tilt, and supine calf blood flow, measured by venous occlusion plethysmography, was used to subgroup POTS patients. A total of 23 POTS patients were partitioned; ten with low blood flow, eight with normal flow and five with high flow. There were ten healthy volunteers. Blood volume was measured by dye dilution. All biochemical measurements were performed whilst supine. Blood volume was decreased in low-flow POTS (2.14±0.12 litres/m2) compared with controls (2.76±0.20 litres/m2), but not in the other subgroups. PRA (plasma renin activity) was decreased in low-flow POTS compared with controls (0.49±0.12 compared with 0.90±0.18 ng of Ang I·ml−1·h−1 respectively), whereas plasma Ang II was increased (89±20 compared with 32±4 ng/l), but not in the other subgroups. PRA correlated with aldosterone (r=+0.71) in all subjects. PRA correlated negatively with blood volume (r=−0.72) in normal- and high-flow POTS, but positively (r=+0.65) in low-flow POTS. PRA correlated positively with Ang II (r=+0.76) in normal- and high-flow POTS, but negatively (r=−0.83) in low-flow POTS. Blood volume was negatively correlated with Ang II (r=−0.66) in normal- and high-flow POTS and in five low-flow POTS patients. The remaining five low-flow POTS patients had reduced blood volume and increased Ang II which was not correlated with blood volume. The data suggest that plasma Ang II is increased in low-flow POTS patients with hypovolaemia, which may contribute to local blood flow dysregulation and reduced NO bioavailability.

scholarly journals Regional blood volume and peripheral blood flow in postural tachycardia syndrome

2004 ◽  
Vol 287 (3) ◽  
pp. H1319-H1327 ◽  
Author(s):  
Julian M. Stewart ◽  
Leslie D. Montgomery
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Supine Position ◽  
Peripheral Blood ◽  
Postural Tachycardia Syndrome ◽  
Peripheral Blood Flow ◽  
Control Subjects ◽  
Postural Tachycardia ◽  
Regional Blood Volume ◽  
Upright Tilt

Variants of postural tachycardia syndrome (POTS) are associated with increased [“high-flow” POTS (HFP)], decreased [“low-flow” POTS (LFP)], and normal [“normal-flow” POTS (NFP)] blood flow measured in the lower extremities while subjects were in the supine position. We propose that postural tachycardia is related to thoracic hypovolemia during orthostasis but that the patterns of peripheral blood flow relate to different mechanisms for thoracic hypovolemia. We studied 37 POTS patients aged 14–21 yr: 14 LFP, 15 NFP, and 8 HFP patients and 12 healthy control subjects. Peripheral blood flow was measured in the supine position by venous occlusion strain-gauge plethysmography of the forearm and calf to subgroup patients. Using indocyanine green techniques, we showed decreased cardiac index (CI) and increased total peripheral resistance (TPR) in LFP, increased CI and decreased TPR in HFP, and unchanged CI and TPR in NFP while subjects were supine compared with control subjects. Blood volume tended to be decreased in LFP compared with control subjects. We used impedance plethysmography to assess regional blood volume redistribution during upright tilt. Thoracic blood volume decreased, whereas splanchnic, pelvic, and leg blood volumes increased, for all subjects during orthostasis but were markedly lower than control for all POTS groups. Splanchnic volume was increased in NFP and LFP. Pelvic blood volume was increased in HFP only. Calf volume was increased above control in HFP and LFP. The results support the hypothesis of (at least) three pathophysiologic variants of POTS distinguished by peripheral blood flow related to characteristic changes in regional circulations. The data demonstrate enhanced thoracic hypovolemia during upright tilt and confirm that POTS is related to inadequate cardiac venous return during orthostasis.

Improved cardiac output and peripheral blood flow after correcting neonatal hyperviscosity

1985 ◽  
Vol 110 (3) ◽  
pp. 707
Author(s):  
Sydney Swetnam ◽  
Dale Alverson ◽  
Steven M. Yabek ◽  
Pam Angelus ◽  
Connie Bakstrom ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Peripheral Blood ◽  
Peripheral Blood Flow

Cardiac Output Changes in Newborns With Hyperbilirubinemia Treated With Phototherapy

PEDIATRICS ◽  
1985 ◽  
Vol 76 (6) ◽  
pp. 918-921
Author(s):  
Frans J. Walther ◽  
Paul Y. K. Wu ◽  
Bijan Siassi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Skin Blood Flow ◽  
Peripheral Blood ◽  
Cardiovascular Effects ◽  
Tissue Perfusion ◽  
Peripheral Blood Flow ◽  
Limb Blood Flow ◽  
Term Infants

Phototherapy is known to increase peripheral blood flow in neonates, but information on the associated cardiovascular effects is not available. Using pulsed Doppler echocardiography we evaluated cardiac output and stroke volume in 12 preterm and 13 term neonates during and after phototherapy. We concomitantly measured arterial limb blood flow by strain gauge plethysmography and skin blood flow by photoplethysmography. Cardiac output decreased by 6% due to reduced stroke volume during phototherapy, whereas total limb blood flow and skin blood flow increased by 38% and 41%, respectively. Peripheral blood flow increments tended to be higher in the preterm than in the term infants. The reduced stroke volume during phototherapy may be an expression of reduced activity of the newborn during phototherapy. For healthy neonates the reduction in cardiac output is minimal, but for sick infants with reduced cardiac output, this reduction may further aggravate the decrease in tissue perfusion.

PS 11-71 INFLUENCE OF BMI ON CARDIAC OUTPUT AND PERIPHERAL BLOOD FLOW IN YOUNG ADULT MALES

2016 ◽  
Vol 34 (Supplement 1) ◽  
pp. e352
Author(s):  
Shitij Arora ◽  
Sumit Garg ◽  
Jawahar Lal Agarwal
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Young Adult ◽  
Peripheral Blood ◽  
Peripheral Blood Flow ◽  
Adult Males ◽  
Young Adult Males

MATHEMATICAL MODELING OF STROKE VOLUME FROM THE PERIPHERAL BLOOD FLOW FOR NON INVASIVE PLETHYSMOGRAPHIC MEASUREMENT OF CARDIAC OUTPUT AND ITS VALIDATION

2017 ◽  
Vol 29 (06) ◽  
pp. 1750041
Author(s):  
Pranali Choudhari ◽  
M. S. Panse
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Peripheral Blood ◽  
Clinical Medicine ◽  
Patient Specific ◽  
Peripheral Blood Flow ◽  
Lung Water ◽  
Non Invasive ◽  
Multiple Variable

The ability to accurately measure Cardiac Output (CO) is important in clinical medicine as it helps in improving diagnosis of abnormalities and appropriate disease management. In spite of being an important vital parameter, it is still missing from the screens of the bedside monitors employed today. This could be due to the invasiveness of the method or the discomfort in the measurement. Invasive methods are most accurate but can be best suited for the intensive care units (ICUs) and surgeries, but for bedside measurement these methods add an unnecessary risk to the life of the patient. The existing non-invasive method employed for CO measurement is the thoracic bioimpedance method, which is risky for patients with cardiovascular diseases and inaccurate for patients with extra vascular lung water. This paper presents a novel method of CO measurement from the peripheral blood flow, which fairly overcomes the disadvantages of the existing method. The impedance pulse has been acquired across the wrist, instead of the thorax. A new stroke volume equation has been modeled by carrying out the finite element simulation of the blood flow and multiple variable regression to incorporate the patient specific factors. The stroke volume thus obtained has been validated for 57 subjects.

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