A clinical trial showed that a nasal spray that patients administer at home, without a physician, successfully and safely treated recurrent episodes of a condition that causes rapid abnormal heart rhythms. The study provides real-world evidence that a wide range of patients can safely and effectively use the experimental drug, called etripamil, to treat recurrent paroxysmal supraventricular tachycardia (PSVT) episodes at home, potentially sparing them the need for repeated hospital trips for more invasive treatments.