You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Disease", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Naloxone", ...], "Disease" : ["Hypotensive", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

A case of ventricular tachycardia related to caffeine pretreatment. Suboptimal seizure duration is commonly encountered in electroconvulsive therapy practice, especially in older patients with higher seizure thresholds. Intravenous caffeine is commonly used to improve seizure duration and quality in such patients and is generally well tolerated aside from occasional reports of relatively benign ventricular ectopy. We describe a patient with no previous history of cardiac disease or arrhythmia who developed sustained bigeminy and 2 brief runs of ventricular tachycardia after caffeine administration. Although intravenous caffeine is generally well tolerated, the clinician should be aware of the potential for unpredictable and serious ventricular arrhythmias.
{"Chemical": ["caffeine"], "Disease": ["ventricular ectopy", "cardiac disease", "arrhythmia", "seizure", "ventricular arrhythmias", "ventricular tachycardia"]}