PURPOSE: Patients with hypertrophic obstructive cardiomyopathy (HOCM), a genetic disorder resulting in idiopathic myocardial thickening, can present the anesthesiologist with significant management difficulties. This report reviews the physiology of this important disease process and describes the use of paravertebral nerve blocks (PVB) in the management of a patient with HOCM who presented for partial mastectomy with axillary lymph node dissection. CLINICAL FEATURES: A 72-yr-old female presented for breast cancer surgery with a significant past medical history of HOCM diagnosed during hospitalization for non-small cell lung cancer. PVB were performed at thoracic levels 1-6 and 5 mL of 0.5% ropivacaine and epinephrine 1:400,000 was injected at each level. Intraoperatively the patient required no other medication for analgesia and was comfortable and conversant during the two-hour procedure. She remained pain free following the operation and did not require any opioid medication until the following day. CONCLUSIONS: PVB provide excellent analgesia and are a useful alternative anesthetic when faced with the HOCM patient requiring major breast surgery.