Chronic postoperative pain is an entity that is usually neglected by anesthetists, but several studies show that the choice of anesthetic technique may interfere with this prevalence. Esmolol is a selective beta-blocker of ultra fast duration that has been studied as a perioperative venous adjuvant with antihyperalgesic and opioid sparing action. The investigators ventured the possibility of this anti-hyperalgesic effect attenuating the chronic pain syndrome post-mastectomy.

Inclusion Criteria:

- Patients previously submitted to the study Analgesic Effect of Intraoperative Esmolol in Mastectomies: a randomized placebo controlled trial

Exclusion Criteria:

• Patient aged less than 18 years and over 65 years;
• Patients who refuse to participate in the study;
• Patients with pulmonary disease;
• Patients with cardiac, renal or hepatic disease;
• Use of psychoactive drug;
• Patients with sinus bradycardia;
• Pregnant women;
• Patients with allergy to dipyrone, morphine;
• Patients with chronic pain prior to the surgical procedure;
• Patients with neurological disorders;
• Patients undergoing surgical resurfacing

Patients previously submitted to the study Analgesic Effect of Intraoperative Esmolol in Mastectomies: a randomized placebo controlled trial, will be submitted to a questionnaire of adapted from DNS4.