Heart suddenly racing? Doctors explain a 30-second technique that may help

It starts without warning. You might be climbing the stairs or relaxing on the sofa when suddenly your heart begins pounding at 160 beats a minute or more. The rhythm feels fast, steady, and completely out of your control.

For people with a particular heart rhythm disorder, doctors have long used a technique that requires no medication. But researchers in England discovered that adding one simple movement made it more than twice as effective.

In their clinical trial, 43% of patients returned to a normal heart rhythm, compared with just 17% using the original technique. However, doctors emphasize that it isn't suitable for every racing heartbeat.

What causes a heart to suddenly race?

One possible cause is supraventricular tachycardia (SVT), a condition in which abnormal electrical signals cause the heart to beat unusually fast.

Unlike the normal increase in heart rate during exercise, SVT can begin suddenly, even while someone is sitting quietly. Episodes may last a few minutes or sometimes several hours.

Doctors sometimes use a technique called the Valsalva maneuver to interrupt the abnormal rhythm. It involves straining against a closed airway, which stimulates the vagus nerve, a nerve involved in regulating heart rate.

The technique has been used for years, but it doesn't always work.

Researchers found that one extra step made a big difference

Between 2013 and 2014, researchers tested an improved version of the technique in 10 emergency departments across England.

The REVERT study, published in The Lancet in 2015, included 428 patients with stable SVT in its main analysis.

Half received the traditional Valsalva maneuver. The others performed the same strain but immediately lay flat while medical staff raised their legs.

The difference was striking.

Only 37 of the 214 patients in the traditional group returned to a normal rhythm within one minute. In the modified group, 93 of 214 patients did.

That meant a success rate of 43% instead of 17%, without adding medication.

How does the modified technique work?

According to a JAMA Network medical demonstration, the technique follows a specific sequence.

The patient starts in a half-sitting position and blows forcefully into an empty 10-milliliter syringe for 15 seconds, creating resistance equivalent to approximately 40 mmHg of pressure.

Immediately afterward, the patient lies flat while someone raises their legs to a 45-degree angle for another 15 seconds. The patient then returns to the half-sitting position.

Raising the legs helps blood return to the heart and strengthens the body's vagal response, which can interrupt certain abnormal electrical signals.

Although the maneuver is straightforward, it should only be attempted at home after an SVT diagnosis and instruction from a healthcare professional.

Not everyone should try this technique

A racing heart doesn't automatically mean SVT. Other conditions, including atrial fibrillation and potentially dangerous heart problems, can cause similar symptoms.

The original trial excluded people with certain medical conditions, including aortic stenosis, a recent heart attack, glaucoma, and retinopathy. Women in the third trimester of pregnancy and people unable to lie flat or raise their legs were also excluded.

Anyone experiencing a racing heartbeat for the first time should seek medical assessment rather than assuming this technique is appropriate.

When a racing heart means calling 911

According to the American Heart Association, a rapid heartbeat accompanied by chest pressure or pain, severe shortness of breath, fainting, or other heart attack warning signs needs immediate medical attention.

Call 911 in the United States, 999 in the UK, or 112 in much of Europe. Do not delay emergency care to attempt the maneuver.

People already diagnosed with SVT should also seek urgent help if an episode lasts longer than usual or produces concerning symptoms.

What if the episodes keep coming back?

The technique may stop an individual episode, but it doesn't cure the underlying condition.

For people experiencing frequent SVT attacks, doctors may recommend medication or a procedure called cardiac ablation.

According to Great Ormond Street Hospital, radiofrequency ablation successfully treats the abnormal electrical pathway in around 90% or more of cases.

The important first step is getting the correct diagnosis. Once doctors know what's causing the racing heartbeat, they can recommend the safest and most effective treatment.

Medical disclaimer: This article is for general information and does not replace professional medical advice. Do not attempt the modified Valsalva maneuver without a confirmed diagnosis and instructions from a qualified healthcare professional.