POTS versus deconditioning: the same or different?

Joyner, Michael J.; Masuki, Shizue

doi:10.1007/s10286-008-0487-7

Cited by 79 publications

(68 citation statements)

References 19 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Panic attack 11 (6) Abbreviation: IQR ϭ interquartile range. a Data are n (%) unless otherwise indicated.…”

Section: Mitral Valve Prolapse 3 (2)mentioning

confidence: 99%

“…3 To a variable degree, orthostatic tachycardia has been shown to be reversible with a structured exercise program. [3][4][5][6] Some researchers advocate that POTS is a disorder of deconditioning alone and can be cured by reconditioning. However, a recent study reported that even though orthostatic tachycardia improves with regular exercise, patients' symptoms remain, 5 suggesting that deconditioning may be a secondary mechanism in patients with POTS.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Deconditioning in patients with orthostatic intolerance

et al. 2012

View full text Add to dashboard Cite

Objective: To study the frequency and degree of deconditioning, clinical features, and relationship between deconditioning and autonomic parameters in patients with orthostatic intolerance. Methods:We retrospectively studied all patients seen for orthostatic intolerance at Mayo Clinic between January 2006 and June 2011, who underwent both standardized autonomic and exercise testing.Results: A total of 184 patients (84 with postural orthostatic tachycardia syndrome [POTS] and 100 without orthostatic tachycardia) fulfilled the inclusion criteria. Of these, 89% were women, and median age was 27.5 years (interquartile range [IQR] 22-37 years). Symptom duration was 4 years (IQR 2-7.8). Of the patients, 90% had deconditioning (reduced maximum oxygen uptake [VO 2max %] Ͻ85%) during exercise. This finding was unrelated to age, gender, or duration of illness. The prevalence of deconditioning was similar between those with POTS (95%) and those with orthostatic intolerance (91%). VO 2max % had a weak correlation with a few autonomic and laboratory parameters but adequate predictors of VO 2max % could not be identified. Conclusion:Reduced VO 2max % consistent with deconditioning is present in almost all patients with orthostatic intolerance and may play a central role in pathophysiology. This finding provides a strong rationale for retraining in the treatment of orthostatic intolerance. None of the autonomic indices are reliable predictors of deconditioning. Neurology ® 2012;79:1435-1439 GLOSSARY BP ϭ blood pressure; DBP ϭ diastolic blood pressure; HR ϭ heart rate; HUT ϭ head-up tilt; II E ϭ early phase II; II L ϭ late phase II; MET ϭ metabolic equivalent; OI ϭ orthostatic intolerance; POTS ϭ postural orthostatic tachycardia syndrome; PP ϭ pulse pressure; RER ϭ respiratory exchange ratio; SBP ϭ systolic blood pressure; TST ϭ thermoregulatory sweat test; VM ϭ Valsalva maneuver; VO 2max ϭ maximum oxygen uptake; VR ϭ Valsalva ratio.The postural tachycardia syndrome (POTS) is a disorder of orthostatic intolerance mostly affecting young and middle-aged women. The pathophysiology of POTS and the role of deconditioning in this syndrome are poorly understood. 1 Recent evidence suggests that POTS is strongly associated with cardiovascular deconditioning. Cardiovascular changes attributable to deconditioning are similar to those seen after prolonged bedrest and space flight. We have emphasized a reduction in stroke volume, 2 whereas others have emphasized cardiac atrophy.3 To a variable degree, orthostatic tachycardia has been shown to be reversible with a structured exercise program.3-6 Some researchers advocate that POTS is a disorder of deconditioning alone and can be cured by reconditioning. However, a recent study reported that even though orthostatic tachycardia improves with regular exercise, patients' symptoms remain, 5 suggesting that deconditioning may be a secondary mechanism in patients with POTS. A comprehensive study formally assessing exercise capacity (the gold standard to assess for deconditioning) in a la...

show abstract

“…Panic attack 11 (6) Abbreviation: IQR ϭ interquartile range. a Data are n (%) unless otherwise indicated.…”

Section: Mitral Valve Prolapse 3 (2)mentioning

confidence: 99%

mentioning

confidence: 99%

Deconditioning in patients with orthostatic intolerance

et al. 2012

View full text Add to dashboard Cite

show abstract

“…1 Although the underlying cause of POTS remains unclear, several mechanisms have been proposed, including sympathetic activation, hypovolemia, and, more recently, deconditioning. [2][3][4] Indeed, endurance exercise training decreases standing heart rate (HR), restores blood volume, and improves orthostatic tolerance and associated symptoms in POTS. [5][6][7] Another frequently used treatment for POTS is nonselective b-adrenergic blockade with propranolol.…”

mentioning

confidence: 99%

Low-dose propranolol and exercise capacity in postural tachycardia syndrome

et al. 2013

View full text Add to dashboard Cite

Objective: To determine the effect of low-dose propranolol on maximal exercise capacity in patients with postural tachycardia syndrome (POTS). Methods:We compared the effect of placebo vs a single low dose of propranolol (20 mg) on peak oxygen consumption (VO 2 max), an established measure of exercise capacity, in 11 patients with POTS and 7 healthy subjects in a randomized, double-blind study. Subjects exercised on a semirecumbent bicycle, with increasing intervals of resistance to maximal effort.Results: Maximal exercise capacity was similar between groups following placebo. Low-dose propranolol improved VO 2 max in patients with POTS (24.5 6 0.7 placebo vs 27.6 6 1.0 mL/min/kg propranolol; p 5 0.024), but not healthy subjects. The increase in VO 2 max in POTS was associated with attenuated peak heart rate responses (142 6 8 propranolol vs 165 6 4 bpm placebo; p 5 0.005) and improved stroke volume (81 6 4 propranolol vs 67 6 3 mL placebo; p 5 0.013). In a separate cohort of POTS patients, neither high-dose propranolol (80 mg) nor metoprolol (100 mg) improved VO 2 max, despite similar lowering of heart rate.Conclusions: These findings suggest that nonselective b-blockade with propranolol, when used at the low doses frequently used for treatment of POTS, may provide a modest beneficial effect to improve heart rate control and exercise capacity. Classification of evidence:This study provides Class II evidence that a single low dose of propranolol (20 mg) as compared with placebo is useful in increasing maximum exercise capacity measured 1 hour after medication. Neurology â 2013;80:1927-1933 GLOSSARY BP 5 blood pressure; CI 5 confidence interval; CO 5 cardiac output; HF RRI 5 high-frequency R-R interval; HR 5 heat rate; LF RRI 5 low-frequency R-R interval; MAP 5 mean arterial pressure; POTS 5 postural tachycardia syndrome; SV 5 stroke volume; SVR 5 systemic vascular resistance; VO 2 max 5 peak oxygen consumption.Postural tachycardia syndrome (POTS) is a heterogeneous disorder characterized by sustained tachycardia ($30 bpm) upon standing, unrelated to medications or other medical conditions. 1 Although the underlying cause of POTS remains unclear, several mechanisms have been proposed, including sympathetic activation, hypovolemia, and, more recently, deconditioning.2-4 Indeed, endurance exercise training decreases standing heart rate (HR), restores blood volume, and improves orthostatic tolerance and associated symptoms in POTS. [5][6][7] Another frequently used treatment for POTS is nonselective b-adrenergic blockade with propranolol. 8,9 At low doses, propranolol reduces standing HR and improves orthostatic symptoms. 8,10,11 In contrast, higher doses can more effectively control tachycardia, but do not improve quality of life or orthostatic symptoms. 5,8 Because b-blockers impair exercise tolerance in healthy subjects, 12 this raises the concern that these drugs would counteract the beneficial effects of exercise training in POTS. We hypothesized, however, that by controlling tachycardia, b-blockers ...

show abstract

“…Importantly, when otherwise fit individuals undergo periods of experimental bedrest or space flight-induced deconditioning, the heart rate responses to orthostatic stress can also increase dramatically. 3,4,6 These observations raised the possibility that endurance exercise training might be an effective treatment for POTS.…”

mentioning

confidence: 99%

“…[3][4][5] The driving forces behind these questions were observations in POTS patients that included low exercise tolerance, high heart rate responses during submaximal exercise, and reduced stroke volume during exercise. These responses to exercise are all considered hallmarks of the untrained or deconditioned state.…”

mentioning

confidence: 99%