Postoperative supraventricular arrhythmias are common in patients after thoracoscopic lobectomy. Inadequate pain control has long been recognised as a significant risk factor for arrhythmias. The performance of ultrasound-guided (USG) thoracic paravertebral block (PVB) is increasing as an ideal technique for postoperative analgesia.We conducted this study to evaluate whether a single-shot USG thoracic PVB would result in fewer postoperative supraventricular tachycardias (SVT) than intercostal nerve blocks (ICNBs) after thoracoscopic pulmonary resection.A randomised controlled study.A single university hospital.Sixty-eight patients undergoing thoracoscopic lobectomy were randomised into two equal groups of 34.For postoperative pain control, all patients received a total of 0.3 ml kg of a mixture containing 0.5% ropivacaine and 1/200 000 epinephrine after placement of needles for either a single thoracic PVB or two individual ICNBs, both guided by ultrasound. Data were obtained during the first 48 postoperative hours.The primary outcome was the incidence of SVT after thoracoscopic pulmonary resection.During the first 48 postoperative hours, the incidences of SVT and atrial fibrillation were lower in the USG thoracic PVB group (14.7 vs. 46.9%, P = 0.004 and 3.0 vs. 18.8%, P = 0.037, respectively). The requirement for β-receptor blockade was more frequent in the ICNBs group than in the PVB group (5.9 vs. 25%, P = 0.033).After placement of the needle using ultrasound guidance, a single-shot thoracic PVB is a well tolerated and effective technique to reduce the incidences of postoperative SVT and atrial fibrillation in patients undergoing thoracoscopic pulmonary resection.http://www.chictr.org/cn/, registration number: ChiCTR-IOR-17010952.