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NCT Number: NCT06961929

IEEM-Heat and Heart Failure

We will test the hypothesis that increasing skin wetness, and thus evaporative cooling, will attenuate the increase in core body temperature and accompanying cardiac stress during heat wave conditions in individuals with congestive heart failure. Secondly, we propose that wearing a water-saturated T-shirt will also be beneficial to attenuate the increase in core body temperature and accompanying cardiac stress during heat wave conditions in individuals with congestive heart failure. To accomplish these objectives, individuals with congestive heart failure and otherwise healthy control individuals will be exposed to the simulated heat wave condition (hot and dry) with the following cooling modalities: A) control trial (no limb immersion or skin wetting), B) skin wetting only trial, and C) water-saturated T-shirt trial in a randomized crossover fashion. Thermoregulatory and cardiovascular responses will be evaluated throughout these simulated heat wave exposures.

Primary outcomes variables will be skin and core temperatures, while secondary variables will include measures of cardiovascular stress, myocardial perfusion, heart rate, and echo-based measures of cardiac function.

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Key information

Conditions

Heart Failure Body Temperature Changes Cardiovascular Diseases Heart Diseases Heat Stress Disorders Hyperthermia Pathological Conditions, Signs and Symptoms Signs and Symptoms Wounds and Injuries

Age range

45 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

for healthy control participants:

  • Participants must be free of any significant underlying medical problems based upon a detailed medical history and physical exam, and normal resting electrocardiogram. Participants must be 45+ years.

Exclusion criteria

for healthy control participants:

  • Known heart disease; other chronic medical conditions requiring regular medical therapy including cancer, diabetes, neurological diseases, and uncontrolled hypertension, lung disease, etc.; as well as serious abnormalities detected on routine screening. Current smokers, as well as individuals who regularly smoked within the past 12 months, will be excluded. Subjects who cannot be age and gender matched to an individual in the heart failure group will be excluded.

Inclusion criteria

for Participants with CHF:

  • The participant must have a diagnosis of congestive heart failure (e.g., heart failure with reduced ejection fraction), with the severity categorized as New York Heart Association (NYHA) class II or III. Participants must be 45+ years.

Exclusion criteria

for Participants with CHF:

-Patients who do not have confirmed diagnosis of NYHA class II or III heart failure will be excluded from the clinical group. Potential participants with cancer, diabetes, neurological disease, lung disease, and/or uncontrolled hypertension will be excluded. Potential participants with a left bundle branch block on ECG will be excluded. Patients on anticoagulant therapy will also be excluded. Current smokers, as well as individuals who regularly smoked within the past 12 months, will be excluded. Further exclusions will include severe valvular or congenital heart disease, acute myocarditis, NYHA Class IV heart failure, and/or manifest/provocable ischemic heart disease.

Treatment and study plan

Control Trial

Other

All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will not be given an experimental cooling modality.

Water-saturated T-shirt trial

Other

All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will also wear a T-shirt that has been saturated with water.

Skin-Wetting Trial

Other

All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will also be sprayed with water periodically.

Primary outcomes

  1. Change in Core Body Temperature while wearing a water-saturated T-shirt

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.

  2. Change in Core Body Temperature in Skin-Wetting Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.

  3. Change in Core Body Temperature in Control Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.

  4. Change in Skin Temperature in while wearing a water-saturated T-shirt

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.

  5. Change in Skin Temperature in Skin-Wetting Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.

  6. Change in Skin Temperature in Control Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.

Secondary outcomes

  1. Change in Heart Rate while wearing a water-saturated T-shirt

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.

  2. Change in Heart Rate in Skin-Wetting Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210minutes.)

    Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.

  3. Change in Heart Rate in Control Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210minutes.)

    Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.

  4. Rate Pressure Product while wearing a water-saturated T-shirt

    Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.

    Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.

  5. Rate Pressure Product in Skin-Wetting Trial

    Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.

    Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.

  6. Rate Pressure Product in Control Trial

    Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.

    Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.

  7. Change in Cardiac Output while wearing a water-saturated T-shirt

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.

  8. Change in Cardiac Output in Skin-Wetting Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.

  9. Cardiac Output in Control Trial

    Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)

    Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.

Study contacts

Contact information is provided by the study sponsor or research team.

Craig Crandall, PhD

CONTACT

[email protected]

214-345-4623

Rachel Cottle, PhD

CONTACT

[email protected]

214-345-4737

Sponsors and collaborators

Lead sponsor

University of Texas Southwestern Medical Center

Other

Registry information

Important dates

Study start
2025
Primary completion
2030
Study completion
2030
First posted
May 8, 2025
Registry last updated
May 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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