Inspiratory resistance improves postural tachycardia: a randomized study.

Abstract

BACKGROUND:

The objective of this study was to determine the effect of inspiratory resistance through an impedance threshold device (ITD) on orthostatic tolerance in patients with postural tachycardia syndrome. We hypothesized that the ITD would result in a greater negative intrathoracic pressure to enhance cardiac venous return, improve stroke volume, and reduce heart rate in these patients.

METHODS AND RESULTS:

We compared the effect of a sham device (sham, no resistance) versus an ITD (increased inspiratory resistance) in 26 patients with postural tachycardia syndrome in a randomized, single-blind, crossover study. Hemodynamic assessments were performed at baseline while supine and during head-up tilt to 70° for 10 minutes. We did not find differences in baseline hemodynamic parameters between the ITD and the sham devices. After 10 minutes of head-up tilt, the heart rate was lower with the ITD versus sham device (102±4 versus 109±4 beat/min, respectively; P=0.003). The ITD also improved stroke volume compared with the sham device (35±2 versus 26±1 mL; P=0.006).

CONCLUSIONS:

These findings suggest that increasing negative intrathoracic pressure with ITD breathing improves heart rate control in patients with postural tachycardia syndrome during upright posture.

CLINICAL TRIAL REGISTRATION:

clinicaltrials.gov; Unique Identifier: NCT00962728.

• Authors: Alfredo Gamboa, Sachin Y Paranjape, Bonnie K Black, Amy C Arnold, Rocío Figueroa, Luis E Okamoto, Victor C Nwazue, Andre Diedrich, W Dale Plummer, William D Dupont, David Robertson, Satish R Raj
• Journal: Circulation. Arrhythmia and electrophysiology (Circ Arrhythm Electrophysiol) Vol. 8 Issue 3 Pg. 651-8 (Jun 2015) ISSN: 1941-3084 [Electronic] United States
• PMID: 25792354 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 American Heart Association, Inc.

Topics

• Adult
• Airway Resistance
• Cross-Over Studies
• Equipment Design
• Female
• Heart Rate
• Humans
• Inhalation
• Male
• Patient Positioning
• Postural Orthostatic Tachycardia Syndrome (diagnosis, physiopathology, therapy)
• Pressure
• Single-Blind Method
• Stroke Volume
• Suction (instrumentation)
• Supine Position
• Tennessee
• Tilt-Table Test
• Time Factors
• Treatment Outcome