Your heart suddenly races and then stops on its own: what is it, and is there a permanent solution?

Being aware of your heartbeat, that is, feeling that your heart is beating harder, faster or more irregularly than usual, is called palpitations. According to the AFib Matters page that the ESC and EHRA prepared for patients, this feeling may come and go. Textbooks usually describe supraventricular tachycardia as occurring in attacks that start suddenly and end suddenly; this is confirmed by a doctor.

But not every fast heartbeat is SVT. AFib Matters also lists excitement, infection, caffeine, extra (ectopic) beats and other arrhythmias as causes. That is why a diagnosis cannot be made from the feeling alone: a recording of the heart, that is, an ECG, shows which rhythm it is.

The main goal is to record the rhythm while the attack is happening, or at least to collect accurate information about the attack. Counting your pulse by hand may make you suspect an irregular rhythm, but according to AFib Matters it cannot reliably confirm it, especially when the heart is beating fast.

Write down when the attack started and ended, how long it lasted, what you were doing and what other sensations came with it: the doctor will need the duration, triggers and accompanying symptoms. If possible, ask your doctor about getting an ECG during an attack.

Sometimes it can, but not always. The REVERT study published in the Lancet in 2015 (Appelboam and colleagues; based on a review in ACEP Now) tested the modified Valsalva maneuver: at the end of the strain, the person lies back and their legs are raised. After one minute, the rhythm returned to normal in 43 % of cases, compared with 17 % with the standard technique.

There are three important caveats. First, the study used a device that measures pressure (a manometer) and an adjustable bed, so you cannot count on the same result at home. Second, the rating “first choice” is the study authors' own, not the level of an approved guideline. Third, the technique does not work for everyone.

Use this technique only after a doctor has confirmed supraventricular tachycardia and taught it to you; do not use it at all if you have chest pain or feel close to fainting.

According to the 2019 ESC guideline on supraventricular tachycardia (as summarized by the ACC), for arrhythmias with a re-entry mechanism and for most focal arrhythmias, ablation should be offered as the first option after a detailed discussion of the risks and benefits. Ablation is a procedure performed with a catheter. Re-entry and focal are terms doctors use to tell types of rhythm disorder apart; which type you have will be shown by testing.

The guideline recommends ablation also when focal tachycardia that starts in the atrium keeps coming back, especially if it continues without stopping or if it has caused tachycardia-induced cardiomyopathy (a disease of the heart muscle). The word “permanent” here is not a promise: results and risks differ from person to person, and you make the decision together with your doctor.

According to AFib Matters, a resting ECG can detect palpitations that are constant, but if attacks come and go, what matters most is a strip recorded during symptoms. That is why an event recorder, which is switched on during an attack, may be used, or, if attacks are very rare, a small monitor placed under the skin (an implantable loop recorder). The doctor chooses which one you need based on how often the attacks happen.

Bring to the appointment:

• an attack diary: the time, how long it lasted, what you were doing, accompanying symptoms;
• a list of the medicines and supplements you take;
• previous ECG and other test results, if you have them.