Lower body muscle preactivation and tensing mitigate symptoms of initial orthostatic hypotension in young females

Sheikh, N.; Ranada, Shaun; Lloyd, Matthew G.; McCarthy, Dallan; Kogut, Karolina; Bourne, Kate; Jorge, Juliana Grael; Lei, Lucy Y.; Sheldon, Robert S.; Exner, Derek V.; Phillips, Aaron A.; Runté, Mary; Raj, Satish R.

doi:10.1016/j.hrthm.2021.12.030

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…Few studies have employed these methods, suggesting underdiagnosis of IOH is likely in patients with PASC. This is important as there are targeted non-pharmacological treatments that can help patients with IOH 14 , 24 , 33 . The POTS hemodynamic criterion was met in 30% of patients with PASC, which is consistent with prior reports 14 , 34 , but higher than the prevalence seen in the general population (0.2%) 25 , and specifically within females aged 20-40 years.…”

Section: Discussionmentioning

confidence: 99%

“…Despite a strong overall female predominance, we found that individuals meeting the cardiovascular criteria for IOH was equally prevalent among males and females. IOH can be a common cause of syncope in individuals with unexplained syncope 33 , 37 , suggesting both males and females are at an equal risk of experiencing a syncopal episode related to PASC.…”

Section: Discussionmentioning

confidence: 99%

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Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

Hira

Baker

Siddiqui

et al. 2023

Canadian Journal of Cardiology

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

Hira

Baker

Siddiqui

et al. 2023

Canadian Journal of Cardiology

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“…6 To our knowledge, there is no literature exploring how the sympathetic nervous system (SNS) affects IOH. In an earlier study, we showed that active muscle precontraction blunts the SBP drop and prevents IOH symptoms 7 ; however, it is unclear whether this was the result of increased sympathetic activity or muscle contraction.…”

mentioning

confidence: 94%

Mitigating Initial Orthostatic Hypotension: Mechanistic Roles of Muscle Contraction Versus Sympathetic Activation

et al. 2022

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Background: Initial orthostatic hypotension (IOH) is defined by a large drop in blood pressure (BP) within 15 s of standing. IOH often presents during an active stand, but not with a passive tilt, suggesting that a muscle activation reflex involving lower body muscles plays an important role. To our knowledge, there is no literature exploring how sympathetic activation affects IOH. We hypothesized involuntary muscle contractions before standing would significantly reduce the drop in BP seen in IOH while increasing sympathetic activity would not. Methods: Study participants performed 4 sit-to-stand maneuvers including a mental stress test (serial 7 mental arithmetic stress test), cold pressor test, electrical stimulation, and no intervention. Continuous heart rate and beat-to-beat BP were measured. Cardiac output and systemic vascular resistance were estimated from these waveforms. Data are presented as mean±SD. Results: A total of 23 female IOH participants (31±8 years) completed the study. The drops in systolic BP following the serial 7 mental arithmetic stress test (−26±12 mm Hg; P =0.004), cold pressor test (−20±15 mm Hg; P <0.001), and electrical stimulation (−28±12 mm Hg; P =0.01) were significantly reduced compared with no intervention (−34±11 mm Hg). The drops in systemic vascular resistance following the serial 7 mental arithmetic stress test (−391±206 dyne×s/cm 5 ; P =0.006) and cold pressor test (−386±179 dyne×s/cm 5 ; P =0.011) were significantly reduced compared with no intervention (−488±173 dyne×s/cm 5 ). Cardiac output was significantly increased upon standing (7±2 L/min) compared with during the sit (6±1 L/min; P <0.001) for electrical stimulation. Conclusion: Sympathetic activation mitigates the BP response in IOH, while involuntary muscle contraction mitigates the BP response and reduces symptoms. Active muscle contractions may induce both of these mechanisms of action in their pretreatment of IOH. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03970551.

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Autonomic Manifestations of Long-COVID Syndrome

Hira,

Karalasingham,

Baker

et al. 2023

Curr Neurol Neurosci Rep

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Lower body muscle preactivation and tensing mitigate symptoms of initial orthostatic hypotension in young females

Cited by 4 publications

References 10 publications

Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

Objective Hemodynamic Cardiovascular Autonomic Abnormalities in Post-Acute Sequelae of COVID-19

Mitigating Initial Orthostatic Hypotension: Mechanistic Roles of Muscle Contraction Versus Sympathetic Activation

Autonomic Manifestations of Long-COVID Syndrome

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