Vagal Maneuvers to Treat Supraventricular Tachycardia
Vagal Maneuvers to Treat Supraventricular Tachycardia
by Greta Kviklyte
Life Saver, AMC
posted on Nov 27, 2021, at 4:42 am
Supraventricular tachycardia (SVT), sometimes called paroxysmal supraventricular tachycardia, refers to a group of conditions affecting the upper chambers of the heart (atria). These conditions occur due to faulty electrical signaling within the heart and cause the heart to beat unusually fast, for as little as a few seconds to as much as a few hours or days.
SVT is rarely fatal, but it can lead to signs and symptoms that are uncomfortable and distressing, including chest pain, shortness of breath, sweating, lightheadedness, dizziness, fainting (syncope) or near fainting, fatigue, pulsing sensations in the neck, and heart palpitations (the feeling that the heart is fluttering, pounding, murmuring, throbbing, or skipping a beat).
To help people manage SVT, doctors rely on multiple interventions including medications, procedures like ablation or electrocardioversion, and vagal maneuvers. One benefit of vagal maneuvers is that patients can learn how to perform these maneuvers on their own, which helps them manage their supraventricular tachycardia symptoms at home.
This blog post discusses what vagal maneuvers are, how they are used to help slow down a person’s heartbeat, and what safety considerations patients and medical providers should be aware of before using vagal maneuvers as part of the first-line treatment for tachycardia.
Did You Know?
The normal resting heartbeat of an adult is between 60 and 100 beats per minute. The normal resting heart rate of an infant (birth to about 3 months of age) ranges from 100 to 150 beats per minute. Between one and three years of age, a child’s resting heart rate should fall between 70 and 110 beats per minute.
By the time a child reaches age 12, their resting heart rate more closely resembles an adult’s, ranging from 55 to 85 beats per minute.
SVT is the most common kind of abnormal heart rhythm in children. But while abnormal heart rhythms can lead to cardiac events in children and infants, SVT is almost never life-threatening in kids or adults.
Understanding Vagal Maneuvers and Their Role in SVT
The vagus nerve (also known as the tenth cranial nerve or CN X) is an important part of the body’s parasympathetic nervous system, which is the “rest and digest” part of the nervous system that facilitates relaxation. The vagus nerve—which travels from the brainstem to the abdomen—helps control things like mood, digestion, and immune function. It also innervates heart muscle fibers and helps control the heart rate.
Vagal maneuvers are techniques intended to stimulate the vagus nerve, which can help slow down electrical activity in a structure in the heart called the atrioventricular (AV) node. To understand why vagal nerve activation is important for managing supraventricular tachycardia, it’s helpful to know a little more about the different types of SVT.
The most common type of SVT is called atrioventricular nodal reentrant tachycardia (AVNRT). AVRNT occurs when there is an extra electrical pathway (reentrant circuit) in or near the AV node that causes the heart to beat too fast.
Another type of SVT is called atrial tachycardia, which includes atrial flutter (the upper chambers of the heartbeat faster than the lower chambers) and atrial fibrillation (the upper chambers of the heartbeat fast and irregularly).
Common risk factors for SVT include family history, heavy smoking or alcohol use, excess caffeine, intense exercise, high stress, drug use, certain medications, pregnancy, advancing age, and underlying medical conditions like lung problems, obesity, thyroid diseases, or other heart valve diseases.
According to 2015 clinical guidelines from the American Heart Association, American College of Cardiology, and Heart Rhythm Society, SVT is common in both outpatient clinical practice and emergency medicine settings. These 2015 clinical guidelines also recommend vagal maneuvers as one of the first lines of treatment for people with SVT.
5 Vagal Maneuvers to Manage Supraventricular Tachycardia
In a 2014 review, Sohinki and Obel note that vagal maneuvers are effective at reversing SVT and returning the heart to a normal rate (sinus rhythm) about 25% of the time, on average. These maneuvers can be performed in a variety of ways. Five techniques are described here:
1. Valsalva Maneuver (Bearing Down)
Many people perform Valsalva maneuvers in daily life, such as when they are lifting something heavy or straining to defecate. Generally speaking, this technique involves a forceful attempt to breathe out even though the airway is closed.
To perform a Valsalva maneuver for SVT in the clinical setting, a patient should lay down in a semi-recumbent (partially reclined) position. They should forcefully exhale against resistance into a pressure measuring device called a manometer (or, alternatively, a large syringe) for about 15 seconds, generating a pressure of 40 mmHg.
Next, the patient lays flat and the provider passively raises the patient’s legs to about 45 degrees. After 15 seconds, the patient returns to the semi-recumbent position. During this maneuver, the patient’s heart rate, blood pressure, and other vital signs are monitored closely.
The Valsalva maneuver is expected to create a physiological response that can be broken down into four phases:
- Phase 1: forced exhalation against resistance increases pressure inside the chest, which temporarily increases pressure inside the aorta (the main artery that carries blood away from the heart); to compensate for this increased aortic pressure, the heart rate decreases
- Phase 2: the increased pressure inside the chest temporarily reduces the amount of blood flowing back to the heart (venous return) and therefore reduces the amount of blood pumped out by the heart (cardiac output); to compensate, the heart rate starts to increase again
- Phase 3: at the end of the forceful exhalation, the pressure inside the aorta decreases, further leading to a compensatory rise in heart rate
- Phase 4: having the patient lay flat with their legs raised increases the venous return to the heart, which again increases the aortic pressure and leads to a compensatory decrease in heart rate
If the Valsalva maneuver works correctly, a person’s heart should return to its normal resting rate once all four phases are complete.
The Valsalva maneuver has a similar effect to sustained forceful coughing. One benefit of coughing is that it is usually easier for patients to do.
3. Cold Stimulus to the Face
The diver’s reflex, recognized as early as the 1700s, is a physiological reflex in humans and other mammals that is triggered in response to holding the breath while submerged in cold water. This causes the heart rate to decrease and the pressure inside peripheral veins to increase, which decreases the amount of work the heart has to do and therefore helps conserve oxygen.
People experiencing SVT can simulate their diver’s reflex by submerging their face in a container of ice or ice-cold water or putting an ice-cold washcloth or icepack on their face. Each type of cold stimulus should last about 10 seconds.
4. Carotid Massage
Only a trained medical professional such as a doctor should perform a carotid massage, which is done while the patient’s neck is extended back and turned away from the side being massaged. This maneuver may help treat SVT by stimulating nerve endings in the carotid arteries that tell the heart to slow down.
To perform this technique, a doctor moves his or her fingers in a gentle circular motion over the carotid artery just beneath the jaw for about 10 seconds. Only one side of the neck should be massaged at a time.
Carotid massage can be used to both diagnose and treat SVT.
The gagging reflex
Gagging stimulates the vagus nerve and can stop an episode of SVT. A tongue depressor is briefly inserted into the patient’s mouth, touching the back of the throat, which causes the person to reflexively gag. The gag reflex stimulates the vagus nerve.
Precautions and Contraindications
While they are simple, non-invasive, and generally effective, vagal maneuvers are not without risk. Patients should never attempt vagal maneuvers without the supervision of a medical provider.
For example, carotid massage is contraindicated in anyone who has a history of ventricular fibrillation or ventricular tachycardia, or in anyone who has had a heart attack, stroke, or transient ischemic attack (TIA or mini-stroke) less than three months ago.
Valsalva maneuvers are contraindicated in patients who have SVT along with:
- An acute heart attack
- Unstable blood pressure (e.g., systolic blood pressure less than 90 mmHg)
- Aortic stenosis
- Carotid artery stenosis
- Certain eye disorders, including glaucoma or retinopathy
Vagal maneuvers may also lead to adverse events including, syncope or heart block (when the electrical signals to the heart are blocked).
One 2018 case report by Nakamori et al described the case of a 79-year-old male who developed atrial fibrillation after performing the Valsalva maneuver when he had SVT following heart surgery. Atrial fibrillation is widely considered the most dangerous type of SVT since it can lead to potentially fatal complications including heart failure, blood clots, and stroke. In this particular case, doctors used medication to help restore the patient’s normal heart rate, which returned within four hours.
Other Treatment and Prevention Options for SVT
As noted, current research suggests that the effectiveness of vagal maneuvers to treat SVT is about 25%, with a success rate ranging from as low as 6% to as high as 54%, depending on the study. What this suggests is that other interventions are often necessary to help terminate tachycardia and reestablish a normal heart rhythm.
These interventions may include:
- Medications, including adenosine and amiodarone
- Cardioversion, in which an electric current is delivered to the heart via patches or paddles on the chest, which helps “shock” the heart back into a normal rhythm
- Ablation, in which a doctor inserts a thin flexible tube called a catheter through a vein or artery (usually in the groin), then uses cold or heat sensors on the end of the catheter to create tiny scars in certain parts of the heart to block faulty electrical signals
In rare instances, some people who experience SVT are treated with a pacemaker. A pacemaker is a small device implanted beneath the skin near the collarbone that helps control a person’s heartbeat.
Individuals can also reduce their risk of SVT and prevent future episodes by making simple and healthy lifestyle changes. This includes:
- Understanding what causes tachycardia for them (identifying personal triggers)
- Not smoking
- Minimizing or eliminating alcohol and caffeine
- Managing stress levels
- Getting enough sleep
- Maintaining a healthy weight (a 2018 study published in The American Journal of Cardiology with more than 67,000 participants found that people who are obese were 40% more likely to develop atrial fibrillation than people who weren’t obese)
- Using medications only as prescribed and knowing which kinds of medications can lead to a rapid heart rate, including antidepressants, blood pressure medications, and even over-the-counter decongestants or cold medications
- Avoiding illegal drugs, including cocaine, ecstasy, or methamphetamines
- Managing other underlying health conditions with the help of a medical provider
Not only can these healthy lifestyle choices help reduce the risk of SVT, but they can also improve overall cardiovascular health.
SVT includes a group of conditions that can cause an abnormally fast heartbeat that can come and go or persist for hours or days. Associated SVT symptoms like lightheadedness, fatigue, and shortness of breath can be incredibly distressing—and can be caused by other health conditions, too. So, always speak with a doctor to get a proper diagnosis.
It’s important to remember that SVT is usually not life-threatening on its own, but certain subtypes of SVT (e.g., atrial fibrillation) may increase the risk of potentially fatal conditions like blood clots, heart attack, or stroke. To learn skills that could save a life, or to update or renew a CPR or First Aid certification conveniently and completely online check Advanced Medical Certification. Share your story of how CPR or First Aid training helped you.