Takeaway

• Vagal manoeuvres often successfully terminate paroxysmal supraventricular tachycardia (SVT).
• Now, a new over-the-counter device that boosts vagal tone could help avoid some emergency department visits.

Why this matters

• Breath-holding, cold water to the face, and Valsalva manoeuvres can terminate stable SVT by inducing a vagal response but may be...