This retrospective, observational study was conducted on consecutive patients who presented with a venomous snakebite at the emergency department (ED) of Wonju Severance Christian Hospital, Wonju College of Medicine, Yonsei University, between May 2011 and October 2014. The study exclusion criteria applied were; an age of <18 years, end-stage renal disease, no admittance for treatment at our hospital, ED arrival >48 hrs after being bitten, and the absence of a measurable serum TnI level within 48 hrs of arrival at the ED.

Diagnostic criteria of venomous snakebite included the presence of one or more of the following: 1) a confirmed two fang wound; 2) a triangular head; 3) a venomous snake confirmed by patient's experience; and 4) abnormal physical and laboratory findings such as shock, tachypnea, bleeding, thrombocytopenia, disseminated intravascular coagulation (DIC), or diplopia despite insufficient other findings.6 When patients had systemic signs and symptoms or severe local symptoms associated with snakebite, antivenin was administered and, if symptoms persisted, antivenin was repeated.

The following information was obtained from medical records: age, gender, site of the bite, ED arrival times, underlying diseases, severity at ED & admission, initial systolic blood pressure, and initial symptoms and signs. A traditional snakebite severity grading scale was used (Table 1).7 Complications including hematologic (anemia,8 thrombocytopenia, prothrombin time/partial thromboplastin time prolongation, DIC,9 and bleeding) and neurologic complications (blurred vision or diplopia) occurring during hospitalization, and mortality were investigated.

Cardiac biochemical markers including hs-TnI were investigated in the ED. A hs-TnI (Siemens Healthcare Diagnostics Inc., Newark, DE, USA) was used to determine blood TnI levels (reference range: <0.046 ng/mL) and myocardial injury was defined as an elevation of hs-TnI within 48 hrs of arrival at the ED.

ACVEs were defined as the occurrence of at least one of the followings: 1) myocardial injury [based on hs-TnI elevation within 48 hrs of presentation or electrocardiogram (ECG) evidence of ischemic change, such as ST elevation, ST depression, or T wave inversion]; 2) shock (defined as hypotension requiring vasopressors); 3) ventricular dysrhythmia (ventricular tachycardia, ventricular fibrillation, torsades des pointes); and 4) cardiac arrest. We investigated ACVEs that developed within 48 hrs of treatment commencement because we wanted to minimize the possibility of ACVEs secondary to malfunctions of other organs or systems, such as, multiple organ failure.

This study was approved by the Institutional Review Board of Wonju College of Medicine, Yonsei University.

Categorical variables are presented as frequencies and percentages, and continuous variables are presented as mean and standard deviation or median and interquartile range after assessments for normality using the Shapiro-Wilk test. The chi-square test or Fisher's exact test was used to compare nominal variables, and the two-sample t-test or the Mann-Whitney U test was used to compare continuous variables. p values of <0.05 were considered statistically significant. The analysis was performed using IBM SPSS 20 Ver. (IBM, Armonk, NY, USA).

A total of 65 consecutive patients were found eligible for this study while 33 patients were excluded from the study due to the following exclusion criteria: age less than 18 years (7 patients), end-stage renal disease (1 patient), patients had not been admitted for treatment in our hospital or transfer out (4 patients), ED arrival more than 48 hrs after snakebite (4 patients), and the absence of serum hs-TnI level within 48 hrs of arrival at the ED (15 patients), and insufficient data (2 patients).

General characteristics are shown in Table 2. Forty six of the patients were male (70.8%) and the ages of the 65 study subjects ranged from 20 to 90 years with a median of 57 years. All patients were bitten in upper and lower extremities. There were 5 patients (7.7%) with cardiac diseases including coronary artery disease (unstable angina 1 patient and myocardial infarction 1 patient), valvular heart disease (aortic regurgitation 1 patient), hypertensive heart disease (hypertensive heart failure 1 patient), and arrhythmia (atrial fibrillation 1 patient). Most common grading of severity was grade II. The common symptoms and signs at initial presentation were pain (65 patients, 100%), edema (53 patients, 81.5%), discoloration (18 patients, 27.7%), and dizziness (9 patients, 13.8%). The most common hematologic complication during hospitalization was anemia (39 patients, 60%), and bleeding developed in 6 patients at puncture site (2 patients), gastrointestinal tract (3 patients), and brain (1 patient). DIC developed in 46.2% of patients. Out of neurologic complications, blurred vision was developed in 3.0%. Other complication was a rhabdomyolysis (13 patients, 20%) and there was no mortality (Table 2).

ACVEs occurred in 9 patients (13.8%); myocardial injury (9 patients, 13.8%) included hs-TnI elevation (7 patients, 10.8%) or ECG determined ischemic change (2 patients, 3.1%), and shock (2 patient, 3.1%). Neither ventricular dysrhythmia nor cardiac arrest was observed. Cardiac biochemical markers analysis revealed median initial levels of hs-TnI of 0.015 ng/mL. ECG showed a T wave inversion in 4 patients (6.2%). QT prolongation was observed in 25 patients (38.5%) (Table 2 and 3).

Underlying cardiac diseases were more common in the ACVEs group than in the non-myocardial injury group (p=0.017). Ho-wever, age, severity, and initial symptoms & signs were not significantly different between the two groups (Table 2).

Regarding complications during hospitalization, 3 patients (5.4%) in the non-ACVEs group and 3 patients (33.3%) in the ACVEs group developed bleeding (p=0.031). Blurred vision or diplopia developed in 2 patients in non-ACVEs group (Table 2).