title: RV contractility and exercise-induced pulmonary hypertension in chronic mountain sickness: a stress echocardiographic and tissue Doppler imaging study.
abstract: OBJECTIVE
  The aim of this study was to evaluate right ventricular (RV) and left ventricular function and pulmonary circulation in chronic mountain sickness (CMS) patients with rest and stress echocardiography compared with healthy high-altitude (HA) dwellers.
  
  
  BACKGROUND
  CMS or Monge's disease is defined by excessive erythrocytosis (hemoglobin >21 g/dl in males, 19 g/dl in females) and severe hypoxemia. In some cases, a moderate or severe increase in pulmonary pressure is present, suggesting a similar pathogenesis of pulmonary hypertension.
  
  
  METHODS
  In La Paz (Bolivia, 3,600 m sea level), 46 CMS patients and 40 HA dwellers of similar age were evaluated at rest and during semisupine bicycle exercise. Pulmonary artery pressure (PAP), pulmonary vascular resistance, and cardiac function were estimated by Doppler echocardiography.
  
  
  RESULTS
  Compared with HA dwellers, CMS patients showed RV dilation at rest (RV mid diameter: 36 ± 5 mm vs. 32 ± 4 mm, CMS vs. HA, p = 0.001) and reduced RV fractional area change both at rest (35 ± 9% vs. 43 ± 9%, p = 0.002) and during exercise (36 ± 9% vs. 43 ± 8%, CMS vs. HA, p = 0.005). The RV systolic longitudinal function (RV-S') decreased in CMS patients, whereas it increased in the control patients (p < 0.0001) at peak stress. The RV end-systolic pressure-area relationship, a load independent surrogate of RV contractility, was similar in CMS patients and HA dwellers with a significant increase in systolic PAP and pulmonary vascular resistance in CMS patients (systolic PAP: 50 ± 12 mm Hg vs. 38 ± 8 mm Hg, CMS vs. HA, p < 0.0001; pulmonary vascular resistance: 2.9 ± 1 mm Hg/min/l vs. 2.2 ± 1 mm Hg/min/l, p = 0.03). Both groups showed comparable systolic and diastolic left ventricular function both at rest and during stress.
  
  
  CONCLUSIONS
  Comparable RV contractile reserve in CMS and HA suggests that the lower resting values of RV function in CMS may represent a physiological adaptation to chronic hypoxic conditions rather than impaired RV function. (Chronic Mountain Sickness, Systemic Vascular Function [CMS]; NCT01182792).
authors.affiliation: Institute of Clinical Physiology, CNR, Pisa, Italy. Electronic address: lorenza@ifc.cnr.it.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Pratali
authors.affiliation: University Hospital of Bern, Cardiology, Bern, Switzerland.
authors.forename: Yves
authors.initials: Y
authors.lastname: Allemann
authors.affiliation: University Hospital of Bern, Cardiology, Bern, Switzerland.
authors.forename: Stefano F
authors.initials: SF
authors.lastname: Rimoldi
authors.affiliation: Institute of Clinical Physiology, CNR, Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Faita
authors.affiliation: University Hospital of Bern, Cardiology, Bern, Switzerland.
authors.forename: Damian
authors.initials: D
authors.lastname: Hutter
authors.affiliation: University Hospital of Bern, Cardiology, Bern, Switzerland.
authors.forename: Emrush
authors.initials: E
authors.lastname: Rexhaj
authors.affiliation: Division of Cardiology, Kantonsspital St. Gallen, St. Gallen, Switzerland.
authors.forename: Roman
authors.initials: R
authors.lastname: Brenner
authors.affiliation: Neurovascular Research Laboratory, Faculty of Health, Science and Sport, University of Glamorgan, Pontypridd, United Kingdom.
authors.forename: Damian M
authors.initials: DM
authors.lastname: Bailey
authors.affiliation: Department of Internal Medicine and Botnar Center for Clinical Research, Lausanne, Switzerland.
authors.forename: Claudio
authors.initials: C
authors.lastname: Sartori
authors.affiliation: Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
authors.forename: Carlos Salinas
authors.initials: CS
authors.lastname: Salmon
authors.affiliation: Instituto Boliviano de Biologia de Altura, La Paz, Bolivia.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Villena
authors.affiliation: University Hospital of Bern, Cardiology, Bern, Switzerland; Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Arica, Chile.
authors.forename: Urs
authors.initials: U
authors.lastname: Scherrer
authors.affiliation: Institute of Clinical Physiology, CNR, Pisa, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Picano
authors.affiliation: Institute of Clinical Physiology, CNR, Pisa, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Sicari
mesh_terms: D000064:Acclimatization; D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000000981:diagnostic imaging* / Q000503:physiopathology; D062186:Arterial Pressure; D001838:Bolivia; D002908:Chronic Disease; D015150:Echocardiography, Doppler; D025401:Echocardiography, Stress; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D011652:Pulmonary Circulation; D013557:Switzerland; D014655:Vascular Resistance; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
keywords: CMS; E; E/e′; HA; Hb; LV; PAP; RV; RV-ESPAR; RV-S′; TDI; chronic mountain sickness; exercise echocardiography; e′; hemoglobin; high altitude; left ventricular; peak early diastolic tissue Doppler imaging velocity of the mitral annulus; peak velocity of early mitral inflow; pulmonary arterial pressure; ratio of early (e′) and late (a′) diastolic tissue Doppler imaging tricuspid peak annular velocities; ratio of peak velocity of early mitral inflow to mitral annular early diastolic peak velocity; right ventricular; right ventricular end-systolic pressure-area relationship; right ventricular function; systolic pulmonary hypertension; tissue Doppler imaging; tissue Doppler imaging peak systolic velocity of the lateral tricuspid valve annulus; tric e′/a′