An electrocardiographic series of flecainide toxicity

Anti-arrhythmic drugs (AADs) uniquely affect the various electrolyte channels in the heart and can slow conduction, increase refractoriness, and/or decrease automaticity with the goal of preventing tachyarrhythmias. Due to these properties, these same drugs are by nature pro-arrhythmic. Vaughan-Williams classification Ic AADs belong to a class of medications that inhibit sodium channels, leading to decreased conduction velocity of myocytes and Purkinje fibers as well as to decreased automaticity of pacemaker cells. When present in toxic amounts, this leads to classic changes on the electrocardiogram (ECG) that are harbingers of potentially lethal arrhythmias. Presented is a clinical series of ECGs that occurred in a patient who presented with flecainide toxicity.

Atrial Flutter With Exercise-Induced 1:1 Atrioventricular Conduction

Typical atrial flutter is a common atrial tachyarrhythmia. Symptoms are typically related to the rate of ventricular response. Although atrial flutter with 1:1 atrioventricular conduction is rare, it is important to recognize because it may precipitate rapid hemodynamic compromise. The authors present a case of exercise-induced 1:1 atrioventricular conduction in a patient with typical atrial flutter.

Acute hydrogen sulfide poisoning in a dairy farmer

INTRODUCTION. Hydrogen sulfide is a lipid-soluble gas produced in occupational settings and from decaying organic matter. We present a 36-year-old man who developed acute respiratory arrest from hydrogen sulfide poisoning while performing work as a dairy farmer.

CASE REPORT

The subject entered a poorly ventilated tank containing degrading eggs and, within seconds, collapsed. Coworkers were able to extract him within minutes but he was apneic. He was intubated by emergency medical services and subsequently managed with supportive care in the intensive care unit. Upon admission, a powerful rotten egg scent was noted and a hydrogen sulfide poisoning was suspected. Serum analysis for the presence of thiosulfate confirmed the diagnosis. Nitrite therapy was not administered as the subject arrived outside of the therapeutic window of effectiveness and showed evidence of excellent oxygenation. His examinations following arrival were consistent with an anoxic brain injury which slowly improved several months after the incident with intensive neuro-rehabilitation.

DISCUSSION

Hydrogen sulfide is a mitochondrial toxin and inhibits cytochrome-aa(3) and prevents cellular aerobic metabolism. Therapies for toxic exposures include removal from the contaminated environment, ventilation with 100% oxygen, and nitrite therapy if administered immediately after exposure. Hyperbaric oxygen (HBO) therapy has anecdotal support and remains controversial.

CONCLUSION

Hydrogen sulfide is a significant occupational health hazard. Education, personal protective equipment, and early treatment are important in improving outcomes.

Rare case of fatal yellow fever vaccine-associated viscerotropic disease

This report describes a case of yellow fever vaccine-associated viscerotropic disease (YEL-AVD) that occurred after vaccination in a 22-year-old female. Our patient presented with a clinical syndrome of fever, headache, nausea, and vomiting, which quickly progressed to multiorgan failure and ultimately death on hospital day 4. YEL-AVD is an extremely rare condition reported only a few times in the literature. The yellow fever vaccine is a known stimulus of systemic inflammation in the body. A mild subclinical viremia develops, which results in a persistent and robust T-helper-cell-dependent antibody response with long-lasting immune protection. The very rare patient may have an aberrant response to the 17D vaccine strain, causing the multiple organ system failure seen in YEL-AVD. Predisposing host factors that contribute to YEL-AVD are not yet known. Treatment for YEL-AVD is supportive. To the authors' knowledge, this patient was the first to have YEL-AVD as a result of standard US military vaccination protocols.