Coronary Artery Disease
Conditions
Brief summary
The purpose of this study is to determine the optimal cooling strategies to alleviate cardiovascular strain of coronary artery disease individuals during a simulated North American and Australian heatwave.
Detailed description
Globally, heatwaves are occurring more frequently, are of greater intensity and longer in duration. The devastating health impacts of extreme heat are increasingly recognized, particularly in vulnerable populations, such as adults with coronary artery disease (CAD). While the most effective cooling strategy during a heatwave is the use of air conditioning (AC), economical concerns can limit AC use among vulnerable populations. In addition, widespread AC use places a significant burden on the electrical grid, causing brown-outs and black-outs during periods of extreme heat. Electric fans offer a cooling strategy with a 50-fold lower power requirement and cost compared to AC. However, the efficacy of fan use during heat waves remains contentious. The primary objective of this study is to identify the optimal cooling strategy to alleviate cardiovascular strain of CAD patients exposed to typical North American heatwave conditions (38°C with 60% relative humidity). The secondary objective is to identify the optimal cooling strategy to alleviate cardiovascular strain of CAD patients exposed to typical Australian heatwave conditions (46°C with 10% relative humidity).
Interventions
OTHERNo intervention
The participant will rest in a seated position.
OTHERFan
A fan placed in front of the participant will provide an airflow of 4 m/s throughout the exposure.
OTHERSkin Wetting
Tap water (\ 18°C) will be applied every 5 minutes to the face, neck, upper and lower arms and upper and lower legs using a spray bottle.
OTHERFan + Skin wetting
A fan placed in front of the participant will provide an airflow of 4 m/s throughout the exposure. In addition, tap water (\ 18°C) will be applied every 5 minutes to the face, neck, upper and lower arms and upper and lower legs using a spray bottle.
Sponsors
National Health and Medical Research Council, Australia
Montreal Heart Institute
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
50 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* History of angiographic coronary disease (≥70% arterial diameter narrowing of at least one major epicardial coronary artery) and/or prior coronary revascularization and/or documented prior acute coronary syndrome and/or stable angina and/or perfusion defect during exercise testing. * No CAD-related hospitalisations or changes in cardiac medications or change in pattern of angina for at least 3 months prior to enrolment
Exclusion criteria
* Body mass index ≥35 kg/m2. * Currently undertaking estrogen therapy. * Evidence of current fluid and electrolyte disorders, anemia, abnormal thyroid function, arrhythmias, diabetes, renal disease, liver disease, cerebrovascular disease, significant pulmonary disease, endocrine abnormalities, significant cognitive impairment, psychiatric disorder, substance abuse, degenerative neurological condition or any other medical condition deemed to pose risk during the proposed experiments. * Uncontrolled hypertension (\>180/110 mmHg). * Recent (\<3 months) coronary bypass surgery. * Ejection fraction \<40% and/or clinical evidence/history of heart failure. * Significant valvular heart disease * Resting ECG abnormalities interfering with observation of ST segment changes during testing.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rate pressure product | Change from baseline to the end of the 3 hour exposure | Rate pressure product, in beats per minute per mmHg |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Body core temperature | Change from baseline to the end of the 3 hour exposure | In degrees Celcius |
Other
| Measure | Time frame | Description |
|---|---|---|
| Skin temperature | Change from baseline to the end of the 3 hour exposure | In degrees Celcius |
| Sweat loss | Change from baseline to the end of the 3 hour exposure | In kilograms |
| Local sweat rate | Measured continously during the 3 hour exposure | In mg per minute per cm2 |
| Skin blood flow | Measured continously during the 3 hour exposure. | In arbitrary perfusion units |
Countries
Canada
Outcome results
None listed