Coexistence of occupational exposure to lead and sleep apnea syndrome as a cause of hypertension and arrhythmias. A case report - Poręba, Rafał; Andrzejak, Ryszard; Derkacz, Arkadiusz; Poręba, Małgorzata; Beck, Bogusław; Steinmetz-Beck, Aleksandra; Broszko-Dziedzic, Katarzyna (Nofer Institute of Occupational Medicine)