title: Valsalva Maneuver in Pulmonary Arterial Hypertension: Susceptibility to Syncope and Autonomic Dysfunction.
abstract: Patients with pulmonary arterial hypertension (PAH) are routinely instructed to avoid performing the Valsalva maneuver for fear of syncope or sudden cardiac death. The mechanism of this action has not been elucidated. We conducted a case-control trial of nine patients with PAH and 15 healthy control subjects to determine if systemic hemodynamic changes during the Valsalva maneuver in these patients invoke greater susceptibility to syncope than healthy control subjects. Metrics commonly employed in autonomic testing were used to assess the degree of autonomic failure.
  
  
  
  Common Valsalva parameters, including adrenergic baroreflex sensitivity, pressure recovery time, systolic BP (SBP) recovery, diastolic BP (DBP) recovery, mean arterial pressure recovery, and the Valsalva ratio, were calculated. Mann-Whitney U tests were used to compare continuous variables. The primary end point was adrenergic baroreflex sensitivity.
  
  
  
  Patients with PAH had lower adrenergic baroreflex sensitivity (9.7 ± 4.6 mm Hg/s vs 18.8 ± 9.2 mm Hg/s; P = .005), longer pressure recovery time (3.6 ± 2.5 s vs 1.7 ± 0.8 s; P = .008), similar SBP recovery (-13 ± 11 mm Hg vs -12 ± 23 mm Hg; P = .640), less DBP recovery (-1 ± 12 mm Hg vs 13 ± 14 mmHg; P = .025), less mean arterial pressure recovery (-5 ± 11 mm Hg vs 5 ± 17 mm Hg; P = .048), and a decreased Valsalva ratio (1.25 ± 0.11 vs 1.60 ± 0.22; P < .001) compared with healthy control subjects.
  
  
  
  Compared with healthy control subjects, patients with PAH are more susceptible to syncope during the Valsalva maneuver because of autonomic dysfunction causing cerebral hypoperfusion. These study patients with PAH exhibited a degree of susceptibility to syncope similar to a spectrum of patients with intermediate autonomic failure who typically experience a SBP drop of 10 to 30 mm Hg with standing.
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN; Division of Cardiovascular Medicine, Department of Medicine, University of Louisville, Louisville, KY.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Mar
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: Victor
authors.initials: V
authors.lastname: Nwazue
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: Bonnie K
authors.initials: BK
authors.lastname: Black
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN; Department of Pharmacology, Vanderbilt University, Nashville, TN.
authors.forename: Italo
authors.initials: I
authors.lastname: Biaggioni
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN.
authors.forename: André
authors.initials: A
authors.lastname: Diedrich
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: Sachin Y
authors.initials: SY
authors.lastname: Paranjape
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: James E
authors.initials: JE
authors.lastname: Loyd
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: Anna R
authors.initials: AR
authors.lastname: Hemnes
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN.
authors.forename: Ivan M
authors.initials: IM
authors.lastname: Robbins
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN; Department of Pharmacology, Vanderbilt University, Nashville, TN; Department of Neurology, Vanderbilt University, Nashville, TN.
authors.forename: David
authors.initials: D
authors.lastname: Robertson
authors.affiliation: Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN; Department of Pharmacology, Vanderbilt University, Nashville, TN; Department of Cardiac Science, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Satish R
authors.initials: SR
authors.lastname: Raj
authors.affiliation: Department of Pediatrics, Vanderbilt University, Nashville, TN. Electronic address: eric.austin@vanderbilt.edu.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Austin
mesh_terms: D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000503:physiopathology*; D017704:Baroreflex; D001794:Blood Pressure; D016022:Case-Control Studies; D065627:Familial Primary Pulmonary Hypertension / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology; D008297:Male; D013575:Syncope / Q000503:physiopathology*; D014636:Valsalva Maneuver
keywords: autonomic function; autonomic nervous; pulmonary arterial hypertension; syncope
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