Transcranial magnetic stimulation (TMS) is quickly making a name for itself in the scientific community as a revolutionary psychiatric treatment, most commonly used for depression.

Because it stimulates brain cells through magnetic pulses, TMS is a non-drug, non-invasive treatment with minimal side effects, making it ideal for patients who have not had success with antidepressants in the past.

TMS was approved by the FDA to treat depression in 2008, and many patients are already enjoying its benefits. However, recent scientific evidence indicating a connection between heart rate and depression suggests that neuro-cardiac-guided-TMS could be an even more effective version of TMS in the near future.

Continue reading to find out:

• How depression can affect heart rate
• What neuro-cardiac-guided TMS is
• Why using this method would improve TMS

Depression and heart rate

While medical professionals have yet to reach an official consensus on whether depression affects heart rate, certain studies have suggested that patients who have been diagnosed with depression are more likely to have lower heart rate variability. This means they have less variation in the lengths of time between heart beats.

Heart rate variability is key to your body’s automatic ability to react to different stimuli in the appropriate ways. This function is largely controlled by the nervous system, which is partly responsible for the regulation of heart rate, blood pressure, breathing, and digestion. Because it jeopardizes your body’s internal balance, low heart rate variability poses a threat to your overall health.

In a 2002 study study, researchers found that patients with major depressive disorder were more likely to have higher resting heart rates and lower heart rate variability than control patients without the disorder. The researchers concluded that there is “a direct correlation to be assumed between the degree of severity of depressive symptoms and modulation of cardiovagal activity; the more severe the depressive symptoms, the lower is the cardiovagal activity.”

The American Heart Association released a 2018 report that detailed a study in which researchers found participants “who scored highest on a clinical screening test for depression as well as those taking anti-depressant medication had more than a 30 percent higher risk for developing atrial fibrillation than people with normal test scores and those not taking medications for depression.”

Atrial fibrillation, or an irregular heart beat, affects around 2.7 millions Americans is one of the most common heart rhythm disorders. It can lead to blood clots and stroke, especially if left untreated.

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Thus, people who suffer a cardiac episode, such as a heart attack, are at a higher risk for developing depression. Similarly, a person with depression who has a heart attack has a lower chance of recovering (from the heart attack) and higher risk of dying from a heart-related death than a person without depression.

This link is speculated to be caused by the nervous or endocrine systems.

Neuro-Cardiac-Guided TMS

What is it?

Neuro-cardiac-guided (NCG) TMS uses the patient’s heart rate to increase the accuracy of the magnetic pulses emitted by the TMS machine.

By monitoring the heartbeat, the TMS technician would be able to tell if the magnetic pulses are reaching the intended area of the brain or not. If the right part of the brain is being stimulated, the heart rate should decelerate. The absence of deceleration would indicate that the technicians needs to adjust the TMS coil’s positioning.

How does it work?

The brain and the heart are in constant communication with each other. By exchanging signals, the two organs can coordinate their respective responses, an example being stress making your heart beat faster. In other words, heart activity affects brain function and vice versa.

NCG-TMS is not the first treatment to use brain-heart synergy to its advantage. For instance, patients are sometimes prescribed blood pressure medication for anxiety because it slows the heart rate, which produces a calming effect.

According to Scott West, M.D., the “NCG process suggests that the heart is connected to the same network involved in depression. Several studies have shown that these brain structures are indeed connected to the heart.”

Because NCG-TMS is still in early stages of development, the treatment method is not yet available to the public. However, at this point in its trial period, evidence so far is encouraging.

The Research Institute Brainclinics in the Netherlands is one facility among many currently investigating NCG-TMS. Results from a 2017 study  indicated that the 10-20 different sites in the brain that are optimal for receiving TMS treatment responded to the stimulation with decelerated heart rate, proving NCG-TMS as a valid localization method.

Why NCG-TMS improves TMS

TMS targets the part of the brain responsible for producing the symptoms of depression. This exact area is located in a slightly different position in every person’s head.

Currently, there are several methods commonly used to determine that the TMS coil is in the correct place on the patient’s head. While these methods produce positive results, they rely quite heavily on estimates and general assumptions based on prior research.

NCG-TMS is a way doctors could individualize the TMS process so that the impact of the magnetic pulses are as direct and precise as possible. This would ensure that the patient receives accurate treatment, which means TMS would be even more effective than it already is now.

Additionally, the NCG method may predict whether TMS will produce positive results in the patient. Unlike antidepressants, which can take up to six weeks to yield results, TMS usually creates a noticeable difference in the patient’s mood after the first couple of sessions. Even better, with NCG, a doctor could potentially see that a patient is chemically incompatible with TMS during his or her initial visit.

After the study at the Research Institute Brainclinics, lead researchers Martijn Arns and Tabitha Iseger concluded “those subjects that do not demonstrate a heart rate deceleration during sessions will not clinically respond to the rTMS treatment.”

As stated, this theory is still only a hypothesis. But if true, it would save a patients a significant of time and energy that otherwise would have been spent waiting for the treatment to take effect.

A Bright Path Ahead for TMS

As science continue to advance, TMS is likely to grow in both success and popularity. Though potential improvements like NCG-TMS are still developing, existing TMS technology is accessible, effective, and covered by most insurances.

TMS is most commonly prescribed for treatment-resistant depression, or depression that has proved unresponsive to treatment with medication and therapy, which are traditional methods for dealing with depression.

Generally painless with few side effects, TMS is also an alternative to patients who have experienced abnormal or severe side effects to antidepressants.  

The future holds great promise for TMS, but that doesn’t make its present any less exciting.