Can TENS unit cause a heart attack?
Transcutaneous Electrical Nerve Stimulation (TENS) is a method commonly used in pain therapy. There is no evidence that the use of TENS can cause heart attacks in a healthy individual. However, there are concerns about the interaction between TENS therapy and cardiac pacemakers.
TENS units have been reported to interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs) [1, 2, 3, 4]. The electric impulses from the TENS can be sensed by these devices as abnormal heart rhythms. In a situation like that, the cardiac devices can trigger an improper shock or change the cardiac pacing [1, 2, 5].
In a study of 107 patients with ICDs who underwent TENS therapy, interference was detected in nearly 16% of them. Most of the ICDs interpreted the TENS electric stimulation as premature ventricular beats. However, in nearly 2% of the interference, the signals were read as ventricular tachycardiac, triggering shock delivery [3].
It has to be noted that at no point does TENS therapy in patients with cardiac devices lead to a heart attack.
Some studies indicate quite the contrary. There are suggestions that the TENS unit can be beneficial for the heart. For instance, one study found that TENS has the potential to be a non-invasive and early treatment for heart failure [6]. Also, in another study, TENS was found to improve lactate metabolism in patients with severe angina pectoris [7].
Regardless of the potential that TENS therapy can have in the treatment of heart conditions, any use of this technique in patients with cardiac disease should be consulted with a doctor [8, 9].
What is a TENS unit?
A TENS unit is a transcutaneous electrical nerve stimulation device. It emits small, targeted electric impulses. These impulses are used to relieve pain as a non-pharmacological therapy. It can be used, especially in chronic pain conditions [9].
The TENS unit is composed of electrode pads connected to a battery and a control center box. The small computer in the control box allows you to adjust the specific frequency of the electric currents [8].
The electric impulses emitted by the TENS unit are low-voltage currents that can range from 10 Hz to 50 Hz. They are locally sent into the painful regions via electrode pads [9].
TENS devices can be used in hospitals, outpatient centers, and domestic settings. It is helpful in the management of high pain sensitivity [9].
The TENS device has a rehabilitation character, not a curative one. It brings short-term relief but does not heal the cause [8].
What are the risk factors and side effects of the TENS unit?
Transcutaneous electrical nerve stimulation is generally considered safe. However, like all therapies, it can have risks and potential side effects.
A common adverse effect of TENS therapy is local irritation of the skin or burns. These side effects occur on the adherence spots of the electrodes and come from too high electrical currents [10, 9].
TENS therapy is a risk factor for anyone who has an electrically susceptible device inside or on the skin. Medical devices like cardiac defibrillators and pacemakers are at the highest risk of serious complications. However, infusion pumps can also be affected by the electric currents from the TENS unit [1, 2].
Some individuals with dermatological conditions are at risk of allergic dermatitis after contact with the pads with the electrodes [9].
The effect of the small electric currents on fetuses has not been explored. Therefore, pregnant women should not use TENS therapy for the time of the gravidity [10, 9]. There could be a potential risk that the currents could interfere with fetal development.
Lastly, TENS therapy can cause small, not dangerous, symptoms in the muscles. The electric stimulation can cause tingling, twitching, or muscle spasms [11].