Landiolol is a ß-adrenergic receptor antagonist with a short elimination half-life which has recently been developed. 1,2 We and others have documented its efficacy as a ß-adrenergic receptor antagonist, when administered as an iv bolus.3,4 Here, we show that an elderly patient with paroxysmal atrial tachycardia was successfully treated with bolus landiolol iv.An 84-yr-old male patient (161 cm, 68 kg) was scheduled for repair of a right femoral fracture under spinal anesthesia. His preoperative electrocardiogram showed a complete right bundle-branch block, and he had a history of palpitations. Holter monitoring demonstrated frequent supraventricular arrhythmias, and these were successfully treated with the class Ia antiarrhythmic agent cibenzoline 150 mg·day -1 before surgery. Spinal anesthesia was performed using isobaric bupivacaine 15 mg at L3/4. Thirty minutes later, he abruptly became tachycardic (190 beats·min -1 ) and was treated with cibenzoline 70 mg iv over two minutes. Until that time, his blood pressure and heart rate had been stable (140-160/90-100 mmHg and 110-115 beats·min -1 , respectively). However, the tachycardia did not respond to this treatment. We subsequently administered three boluses of landiolol 5 mg iv (over ten seconds each). After a cumulated 15 mg iv dose of landiolol, his heart rate decreased to 95 beats·min -1 , normal sinus rhythm (Figure), without any hypotensive episode (blood pressure 135/90 mmHg). The remainder of the anesthetic was uneventful, whereas two hours after surgery, he again suffered a similar episode of tachycardia, for which cibenzoline 30 mg iv was ineffective. In this instance, iv volume replacement therapy including blood transfusion gradually restored normal heart rate.Bolus landiolol (0.1-0.3 mg·kg -1 iv) is effective to prevent tachycardia in response to tracheal intubation without affecting blood pressure.3 For our patient, we administered the higher dose of landiolol to treat the tachyarrhythmia. This drug was effective without inducing hypotension even in such an elderly patient. Importantly, the arrhythmia we managed was insensitive to a class Ia antiarrhythmic agent, indicating that landiolol can be used as an alternative when tachyarrhythmia is refractory to conventional therapy.