chemotherapy agents can exert toxic effects on the heart (examples include anthracycline, cyclophosphamide, 5-fluorouracil, and cisplatin). several toxins and venoms can also lead to heart muscle injury (scorpion venom, snake venom, and venom from jellyfish and centipedes). carbon monoxide poisoning or cyanide poisoning can also be accompanied by release of troponins due to hypoxic cardiotoxic effects. cardiac injury occurs in about one-third of severe co poisoning cases, and troponin screening is appropriate in these patients.