Severe palmar and/or axillary hyperhidrosis can be socially and psychologically very disturbing. We present a case of a patient who suffered from a 43 s asystolic cardiac arrest the night following a second contralateral thoracoscopic T(2)-T(3) sympathectomy for severe axillary and truncal hyperhidrosis. The cardiovascular effects of cervico-dorsal sympathectomy will be reviewed. Evaluation required to prevent such a serious cardiac complication will also be discussed.