Hyperventilation facilitates radiation treatment of cardiac arrhythmias

Hyperventilate to better monitor heart rate. Previously used by the medical profession for the diagnosis of ischemic heart disease, this technique is proving to be an effective treatment for cardiac arrhythmias, when the heartbeat becomes irregular.

The study, conducted at the University of Birmingham (UK) and published in the journal Frontiers in Physiology, says the technique of hyperventilating conscious, untreated patients through an oxygen mask can go a long way in treating irregular heartbeats. According to researchers, if people with heart conditions are asked to safely hold their breath for more than 5 minutes, it can help treat irregular heartbeats.

We speak of hyperventilation when we ask a person to exaggerate his way of breathing by pushing it to the maximum, both at the level of inspiration and expiration. This technique has the consequence of changing the proportions of gases contained in our blood, by increasing the supply of oxygen to the detriment of carbon dioxide. The team knows that hyperventilation can cause hypocapnia, which is a decrease in blood pressure accompanied by a drop in carbon dioxide in the blood. This reaction in turn results in a temporary constriction of the coronary arteries.

Disappearance of angina pectoris

For this study, the research team called on 18 volunteers, all non-smokers and in good health, aged between 20 and 30 years. At the same time, they also tested 10 men between the ages of 43 and 72, all of whom had previously suffered from angina and currently had severe coronary disease awaiting bypass surgery. Angina pectoris, also called angina, is one of the characteristic symptoms of coronary artery disease, which occurs when the heart does not have enough oxygen, and which causes severe pain in the chest, with the feeling of a heart “caught in a vice”.

Equipped with respiratory masks and surrounded by a medical team, the researchers asked the subjects to hold their breath for five minutes. By practicing holding their breath for as long as possible before exhaling and starting again, subjects put themselves in a situation of hyperventilation.

In “normal” subjects, this hyperventilation caused hypocapnia, which was accompanied by a significant drop in carbon dioxide in the blood and an increase in the average heart rate. However, the researchers found that hypocapnia did not cause any particular changes to their heart.

On the other hand, the same test taken by subjects suffering from coronary artery disease gave surprising results. The drop in carbon dioxide in the blood had no effect on their heart rate or blood pressure. Better still, during the hypocapnia phase, none of the participants suffered from any respiratory discomfort or angina pectoris, whereas the latter occurs when the heart is under oxygenated.

The study’s lead author, Dr Michael Parkes, a researcher at the University of Birmingham’s School of Sport, Exercise and Rehabilitation Sciences, explains that initially the research team wanted to find out if this effect could be exploited as an “early warning system” to diagnose coronary heart disease.

Promising results

For the research team, further work is needed in this area to clinically establish it as a potential treatment, they confirm with this study that mechanical hyperventilation and hypocapnia are well tolerated and may be safe for patients. suffering from angina pectoris.

This new finding demonstrates that stopping breathing for more than five minutes can support an emerging new technique in which radiation therapy, instead of radiofrequency or freezing, can be used for cardiac ablation. The procedure in which people with arrhythmias undergo targeted radiation therapy, applied from outside the chest, to destroy tissue allowing incorrect electrical signals to cause abnormal heart rhythms, holds promise.

According to Michael Parkes, breathing is problematic since each of them causes the heart to move in the chest. “There is still little awareness of the simplicity, availability and safety of non-invasive mechanical hyperventilation”. The next step is to test this technique in patients with cardiac arrhythmias to see if they too can hold their breath long enough to apply radiation therapy.