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A study on the effect of hydrogen inhalation therapy to prevent the early return of atrial fibrillation in patients after heart ablation treatment.

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is being conducted to investigate the efficacy of inhaled hydrogen on preventing the early return of atrial fibrillation, a condition where the heart beats irregularly or too fast, following a medical procedure called ablation. Ablation is a method used to treat heart rhythm problems by neutralizing the tiny areas of heart tissue that trigger irregular heartbeats. The treatment involves breathing in a specific mixture of hydrogen and nitrogen through the nose.

Participants in this study will be assigned to receive either the inhaled gas or a placebo. The process involves monitoring the heart rhythm and the overall well-being of individuals for a period of three months to see if the treatment helps reduce the recurrence of the irregular heartbeat and improves how patients feel in their daily lives.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Hydrogen therapy administration

    The hydrogen gas mixture (consisting of 3.6% hydrogen and 96.4% nitrogen) is administered through the nose.

  2. Step 2

    Monitoring and assessments

    During the three-month period following the heart procedure (ablation), any episodes of atrial fibrillation, atrial flutter, or atrial tachycardia lasting at least 30 seconds are monitored to check for recurrence.

    The quality of life is assessed by comparing scores from the start of the study to the three-month mark using a specific scale called AFEQT.

    The number of hospital stays or medical procedures used to restore a normal heart rhythm, such as electrical or drug-induced cardioversions, is recorded.

    blood tests are performed to measure levels of inflammation markers (specifically gb, crpus, and il-6) within 24 hours before the heart procedure and between 24 and 48 hours after the procedure.

    Any side effects or adverse events are documented and graded.

    questionnaires regarding the acceptance of the hydrogen therapy are completed upon hospital admission and again when the hydrogen therapy is finished.

  3. Step 3

    Long-term follow-up

    The status of the heart rhythm is monitored for late recurrence, which refers to any issues occurring after the initial three months and up to 12 months after the heart procedure.

Who can join the trial?

7 criteria

  • You must be at least 18 years old.
  • You must have atrial fibrillation, which is an irregular and often rapid heart rhythm, that is either paroxysmal (comes and goes) or persistent (stays for a longer period), and the symptoms must have lasted for less than 6 months.
  • You must be a candidate for your first atrial fibrillation ablation, which is a medical procedure used to treat heart rhythm problems by creating small scars in the heart tissue to block irregular electrical signals. This can include procedures like cryoablation (using extreme cold) or electroporation (using electrical pulses).
  • You must be able to understand and agree to follow all the study procedures.
  • You must own a smartphone.
  • You must be enrolled in a social security program or have similar insurance coverage rights.
  • You must sign the informed consent form, which is a document that explains the study details and confirms your agreement to participate.

Who cannot join the trial?

13 criteria

  • Being older than 80 years of age.
  • Being a protected person, which includes pregnant women, women in labor, breastfeeding mothers, or people who are not legally able to give their own consent (such as minors or people under legal protection).
  • Being someone who is currently in a psychiatric care facility or someone who is currently in jail or under judicial supervision.
  • Being a person who is currently staying in a healthcare or social care facility for reasons other than participating in research.
  • Having a hierarchical relationship with the main doctor leading the study, meaning you work directly under them.
  • Having a left atrial diameter (the width of the upper left chamber of the heart) that is 50 millimeters or larger when measured by a TEE (a type of ultrasound where a probe is placed in the throat to look at the heart).
  • Having a history of AF ablation, which is a medical procedure used to treat an irregular heartbeat called atrial fibrillation.
  • Having previously undergone radiofrequency ablation, a specific method of treating heart rhythm problems using heat.
  • Being on long-term anti-inflammatory treatment, which refers to medicine taken for a long time to reduce swelling or irritation in the body.
  • Using gas administration equipment, such as CPAP or NIV (machines that help a person breathe by providing air pressure through a mask).
  • Being a woman of childbearing potential, meaning a woman who is capable of becoming pregnant.
  • Being unable to cooperate with the requirements of the study.
  • Currently being in an exclusion period from a different medical study.
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Investigated drugs

Hydrogen is a medicinal gas that is inhaled through the nose to see if it can help prevent the heart rhythm disorder from coming back after a procedure to fix it and to help improve how a person feels in their daily life.

What is already known about the treatment

Hydrogen gas mixture - This compressed gas is administered through the nose via inhalation to help treat heart rhythm issues. While currently being studied for its potential benefits, this treatment aims to protect heart cells by reducing harmful oxidative stress and inflammation at a molecular level. It is classified as a medicinal gas and is being investigated for its ability to prevent the return of irregular heartbeats after a specific heart procedure.

Investigated diseases

Atrial fibrillation - This is a condition characterized by an irregular and often rapid heart rate. It occurs when the upper chambers of the heart, called the atria, beat out of sync with the lower chambers. This irregular electrical activity can cause the heart to quiver instead of pumping effectively. Over time, the heart rhythm may become increasingly unstable. This condition can lead to various changes in how the heart functions during its pumping cycle.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-520131-33-00Protocol code38RC22.0404Estimated enrolment136 patientsSponsorCentre Hospitalier Universitaire Grenoble Alpes

sourced from the EU Clinical Trials Register and site verification

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