Acute Exposure to High Altitude on Heart Rate and Ventilation During Exercise

Study Overview
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Brief Summary
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Randomized crossover trial in patients with Pulmonary Hypertension (PAH, CTEPH) to assess the acute response to High Altitude (Säntis; 2500m above sea level) on heart rate and Ventilation changes under exercise.

Detailed Description
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Low altitude baseline measurements will be performed in Zurich (460m asl) including Echocardiography, Right heart catheterization, 6MWT, pulmonary function test, clinical assessment and blood gas Analysis. Randomly assigned to the order of testing, the participants will be tested in Low Altitude (Zurich, 470m) and at High Altitude (2500m). During the exposure to High Altitude (2500m) and Low Altitude (Zurich; 470m) of up to 5 hours, the participants' heart rate and Ventilation will be compared under exercise.

Official Title
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Acute Exposure to Hypoxia in Precapillary Pulmonary Hypertension: Physiological and Clinical Effects at Rest and During Exercise

Conditions
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Pulmonary Hypertension

Intervention / Treatment
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* Other: Assessment at Low Altitude (470m above sea level)
* Other: Exposure to High Altitude (2500m above sea level)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed consent PH diagnosed according to internation Guidelines: mPAP ≥ 25 mmHg along with a PAWP ≤15 mmHg during right heart catheterization at the time of Initial diagnosis PH class 1 (PAH) or 4 (CTEPH) Stable condition, on the same medication for > 4 weeks Patient live permanently at an altitude < 1000m asl. Exclusion Criteria: Resting PaO2 ≤7.3 kPA corresponding to the requirement of long-term oxygen therapy > 16hour daily (nocturnal oxygen therapy alone is allowed) Severe daytime hypercapnia (pCO2 > 6.5 kPa) Susceptibility to high altitude related diseases (AMS, HAPE, etc.) based on previous experienced discomfort at altitudes. Exposure to an altitude >1500m for ≥3 nights during the last 4 weeks before the study participation Residence > 1000m above sea level Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, neurological or orthopedic problems with Walking disability Women who are pregnant or breast feeding

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Including a baseline assessment and assessments at Low alitude and High altitude
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Order A<br>The participants will be tested in Zurich (Low altitude: 470m above sea level) and consecutively at High Altitude(Säntis; 2500m above sea Level) | Other: Assessment at Low Altitude (470m above sea level)<br>* Assessment at Low Altitude (in Zurich; 470m above sea level) in order to compare this data with High altitude exposure<br>Other: Exposure to High Altitude (2500m above sea level)<br>* Exposure to High Altitude (Säntis; 2500m above sea level) for approximately 5 hours<br>|
| Experimental: Order B<br>The participants will be tested at High Altitude (Säntis; 2500m above sea level) and consecutively in Zurich (Low altitude; 470m above sea level). | Other: Assessment at Low Altitude (470m above sea level)<br>* Assessment at Low Altitude (in Zurich; 470m above sea level) in order to compare this data with High altitude exposure<br>Other: Exposure to High Altitude (2500m above sea level)<br>* Exposure to High Altitude (Säntis; 2500m above sea level) for approximately 5 hours<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate under exercise | Change in heart rate under exercise during the exposure to High Altitude (2500m above sea level) and Low Altitude (Zurich; 470m). | within 5 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ventilation under exercise | Change in Ventilation under exercise during the exposure to High Altitude | within 5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Altitude, Exercise, Ventilation, Heart rate