Cardiac Manifestations Following Suspected Cobra ( Naja samarensis ) Bites in Eastern Visayas, Philippines: A Case Series

Abstract

Naja samarensis , a World Health Organization Category 1 venomous snake endemic to the Philippines, causes neurotoxic envenomation, but cardiac complications are rarely documented. Case 1 is a 71-y-old hypertensive male who presented with altered consciousness, ptosis, and dysarthria. Following antivenom administration, he developed supraventricular tachycardia (180 beats/min) requiring adenosine. He recovered after 16 ampules of purified cobra antivenom and was discharged on Day 5. Case 2 is a 66-y-old hypertensive male who presented with neurotoxic symptoms and atrial fibrillation (180 beats/min). Following administration of Taradoc, he acutely deteriorated with hypotension and recurrent atrial fibrillation (200 beats/min), requiring another cardioversion. He subsequently developed progressive pulmonary edema and respiratory failure, leading to death. Case 3 is a 50-y-old female who presented with neurotoxic symptoms, chest heaviness, and elevated troponin (2 ng·mL –1 ). Electrocardiogram revealed ST elevation, suggesting myocardial injury. Following neostigmine administration, neurotoxic symptoms improved, although dyspnea on exertion persisted. Species identification was based on the reported snake appearance (black and yellow coloration), geographic distribution of venomous snakes in Eastern Visayas, and clinical presentation consistent with neurotoxic cobra envenomation. No snake specimens were physically available for species verification in any of the 3 cases. N samarensis envenomation may be associated with life-threatening cardiac complications, including tachyarrhythmia and myocardial injury. Management priorities include the use of antivenoms with established efficacy, differentiation of venom-induced myocardial injury from acute coronary syndrome, and continuous electrocardiographic monitoring with cardiac biomarker assessment.