Leg crossing improves orthostatic tolerance in healthy subjects: a placebo-controlled crossover study

C T Paul Krediet, Johannes J van Lieshout, Lysander W J Bogert, Rogier V Immink, Yu-Sok Kim, Wouter Wieling

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Vasovagal syncope is the most common cause of transient loss of consciousness, and recurrent vasovagal fainting has a profound impact on quality of life. Physical countermaneuvers are applied as a means of tertiary prevention but have so far only proven useful at the onset of a faint. This placebo-controlled crossover study tested the hypothesis that leg crossing increases orthostatic tolerance. Nine naïve healthy subjects [6 females, median age 25 yr (range 20-41 yr), mean body mass index 23 (SD 2)] were subjected to passive head-up tilt combined with a graded lower body negative pressure challenge (20, 40, and 60 mmHg) determining orthostatic tolerance thrice, in randomized order: 1) control, 2) with leg crossing, and 3) with oral placebo. Blood pressure (Finometer), heart rate, and changes in thoracic blood volume (impedance), stroke volume, and cardiac output (Modelflow) were followed during orthostatic stress. Primary outcome was time to presyncope (systolic blood pressure </=85 mmHg, heart rate >/=140 beats/min). With leg crossing, orthostatic tolerance increased from 26 +/- 2 to 34 +/- 2 min (placebo 23 +/- 3 min, P < 0.001). During leg crossing, mean arterial pressure (81 vs. 81 mmHg) and cardiac output (95 vs. 94% supine) remained unchanged; heart rate increase was lower (13 vs. 18 beats/min, P < 0.05); stroke volume was higher (79 vs. 74% supine, P < 0.05); and there was a trend toward lower thoracic impedance. Leg crossing increases orthostatic tolerance in healthy human subjects. As a measure of prevention, it is a worthwhile addition to the management of vasovagal syncope.

Original languageEnglish
Pages (from-to)H1768-72
JournalAmerican Journal of Physiology. Heart and Circulatory Physiology
Volume291
Issue number4
DOIs
Publication statusPublished - Oct 2006

Cite this

Krediet, C T Paul ; van Lieshout, Johannes J ; Bogert, Lysander W J ; Immink, Rogier V ; Kim, Yu-Sok ; Wieling, Wouter. / Leg crossing improves orthostatic tolerance in healthy subjects : a placebo-controlled crossover study. In: American Journal of Physiology. Heart and Circulatory Physiology. 2006 ; Vol. 291, No. 4. pp. H1768-72.
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abstract = "Vasovagal syncope is the most common cause of transient loss of consciousness, and recurrent vasovagal fainting has a profound impact on quality of life. Physical countermaneuvers are applied as a means of tertiary prevention but have so far only proven useful at the onset of a faint. This placebo-controlled crossover study tested the hypothesis that leg crossing increases orthostatic tolerance. Nine na{\"i}ve healthy subjects [6 females, median age 25 yr (range 20-41 yr), mean body mass index 23 (SD 2)] were subjected to passive head-up tilt combined with a graded lower body negative pressure challenge (20, 40, and 60 mmHg) determining orthostatic tolerance thrice, in randomized order: 1) control, 2) with leg crossing, and 3) with oral placebo. Blood pressure (Finometer), heart rate, and changes in thoracic blood volume (impedance), stroke volume, and cardiac output (Modelflow) were followed during orthostatic stress. Primary outcome was time to presyncope (systolic blood pressure /=140 beats/min). With leg crossing, orthostatic tolerance increased from 26 +/- 2 to 34 +/- 2 min (placebo 23 +/- 3 min, P < 0.001). During leg crossing, mean arterial pressure (81 vs. 81 mmHg) and cardiac output (95 vs. 94{\%} supine) remained unchanged; heart rate increase was lower (13 vs. 18 beats/min, P < 0.05); stroke volume was higher (79 vs. 74{\%} supine, P < 0.05); and there was a trend toward lower thoracic impedance. Leg crossing increases orthostatic tolerance in healthy human subjects. As a measure of prevention, it is a worthwhile addition to the management of vasovagal syncope.",
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Leg crossing improves orthostatic tolerance in healthy subjects : a placebo-controlled crossover study. / Krediet, C T Paul; van Lieshout, Johannes J; Bogert, Lysander W J; Immink, Rogier V; Kim, Yu-Sok; Wieling, Wouter.

In: American Journal of Physiology. Heart and Circulatory Physiology, Vol. 291, No. 4, 10.2006, p. H1768-72.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Leg crossing improves orthostatic tolerance in healthy subjects

T2 - a placebo-controlled crossover study

AU - Krediet, C T Paul

AU - van Lieshout, Johannes J

AU - Bogert, Lysander W J

AU - Immink, Rogier V

AU - Kim, Yu-Sok

AU - Wieling, Wouter

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AB - Vasovagal syncope is the most common cause of transient loss of consciousness, and recurrent vasovagal fainting has a profound impact on quality of life. Physical countermaneuvers are applied as a means of tertiary prevention but have so far only proven useful at the onset of a faint. This placebo-controlled crossover study tested the hypothesis that leg crossing increases orthostatic tolerance. Nine naïve healthy subjects [6 females, median age 25 yr (range 20-41 yr), mean body mass index 23 (SD 2)] were subjected to passive head-up tilt combined with a graded lower body negative pressure challenge (20, 40, and 60 mmHg) determining orthostatic tolerance thrice, in randomized order: 1) control, 2) with leg crossing, and 3) with oral placebo. Blood pressure (Finometer), heart rate, and changes in thoracic blood volume (impedance), stroke volume, and cardiac output (Modelflow) were followed during orthostatic stress. Primary outcome was time to presyncope (systolic blood pressure /=140 beats/min). With leg crossing, orthostatic tolerance increased from 26 +/- 2 to 34 +/- 2 min (placebo 23 +/- 3 min, P < 0.001). During leg crossing, mean arterial pressure (81 vs. 81 mmHg) and cardiac output (95 vs. 94% supine) remained unchanged; heart rate increase was lower (13 vs. 18 beats/min, P < 0.05); stroke volume was higher (79 vs. 74% supine, P < 0.05); and there was a trend toward lower thoracic impedance. Leg crossing increases orthostatic tolerance in healthy human subjects. As a measure of prevention, it is a worthwhile addition to the management of vasovagal syncope.

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KW - Cross-Over Studies

KW - Dizziness/physiopathology

KW - Female

KW - Heart Rate/physiology

KW - Hemodynamics/physiology

KW - Humans

KW - Leg/blood supply

KW - Lower Body Negative Pressure

KW - Male

KW - Posture

KW - Regional Blood Flow/physiology

KW - Stroke Volume/physiology

KW - Syncope, Vasovagal/physiopathology

KW - Tilt-Table Test

U2 - 10.1152/ajpheart.00287.2006

DO - 10.1152/ajpheart.00287.2006

M3 - Article

VL - 291

SP - H1768-72

JO - American Journal of Physiology. Heart and Circulatory Physiology

JF - American Journal of Physiology. Heart and Circulatory Physiology

SN - 0363-6135

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ER -