Research presented at EACVI 2023, a scientific congress of the European Society of Cardiology (ESC), found that hyperbaric oxygen therapy enhances the heart’s ability to contract correctly. Study author Professor Marina Leitman of the Sackler School of Medicine, Tel Aviv University and Shamir Medical Centre, Be’er Ya’akov, Israel, said, “The study suggests that hyperbaric oxygen therapy can be beneficial in patients with long Covid.”
They added, “We used a sensitive measure of cardiac function which is not routinely performed in all centres. More studies are needed to determine which patients will benefit the most, but it may be that all long Covid patients should have an assessment of global longitudinal strain and be offered hyperbaric oxygen therapy if heart function is reduced.”
While most Covid-19 sufferers fully recover, 10-20 per cent of patients develop long Covid, also called post-Covid conditions or syndrome. Symptoms include shortness of breath, fatigue, cough, chest pain, rapid or irregular heartbeats, body aches, rashes, loss of taste or smell, nausea, vomiting, diarrhea, headache, dizziness, insomnia, brain fog, depression and anxiety.
Patients with post-Covid syndrome may also develop cardiac dysfunction and are at increased risk of cardiovascular disorders. The randomised controlled double-blind trial evaluated the effect of hyperbaric oxygen therapy (HBOT) on the cardiac function of long Covid patients. HBOT involves inhalation of 100 per cent pure oxygen at high pressure to increase delivery to the body’s tissues, which is particularly beneficial for tissues that are starved of oxygen due to injury or inflammation. HBOT is an established treatment for non-healing wounds, decompression sickness in divers, carbon monoxide poisoning, radiation injury and certain types of infections.
The study enrolled 60 post-Covid syndrome patients with ongoing symptoms for at least three months after having mild to moderate symptomatic Covid-19 confirmed by a PCR test. Both hospitalised and non-hospitalised patients were included. Severe Covid cases were excluded. Patients were randomised to HBOT or a sham procedure in a 1:1 ratio. Each patient had five sessions per week over eight weeks, for a total of 40 sessions. The HBOT group received 100% oxygen through a mask at a pressure of 2 atmospheres for 90 minutes, with 5-minute air breaks every 20 minutes. The sham group breathed 21% oxygen by mask at 1 atmosphere for 90 minutes. All participants underwent echocardiography at baseline (before the first session) and 1 to 3 weeks after the last session.
Echocardiography was used to assess left ventricular global longitudinal strain (GLS), measuring the heart's ability to contract and relax lengthwise. It indicates how well the heart functions and can help detect early signs of heart disease. A healthy heart will have a GLS value of around -20%, meaning the heart muscle can properly contract and relax in the longitudinal direction. Reduced GLS is an early marker that the heart cannot contract and relax effectively.
Professor Leitman said, “It was notable that almost half of long Covid patients had impaired cardiac function at baseline according to GLS despite all participants having a normal ejection fraction, which is the standard method for measuring the heart's ability to contract. This means that ejection fraction is not sensitive enough to identify long Covid patients with reduced heart function.”