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: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. 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:

Plasma norepinephrine and mortality . Plasma norepinephrine levels , which reflect sympathetic nervous system activity , are almost universally elevated in patients with left ventricular dysfunction . This elevation occurs in patients with overt , symptomatic heart failure ( HF ) and in patients with asymptomatic left ventricular dysfunction . Evidence suggests that the elevation in plasma norepinephrine levels can be at least partly attributed to an increase in sympathetic nervous system activity . It has become evident that elevated plasma norepinephrine levels are directly related to prognosis ; patients with levels > 900 pg/ml have a poor prognosis and shortened life expectancy . However , plasma norepinephrine levels bear little relationship to physiologic and clinical variables observed in HF , including ejection fraction and exercise capacity . Data from the V-HeFT II show that at 2-year follow-up , a progressive rise of plasma norepinephrine was observed in both treatment arms , suggesting that disease progresses despite treatment with either an angiotensin-converting enzyme inhibitor , enalapril , or vasodilator therapy with hydralazine/isosorbide dinitrate . It is possible that interventions aimed at the progressive neurohormonal activation that occurs in HF may improve the course of illness . Further study is needed to test this hypothesis .
{"Intervention": ["enalapril", "hydralazine/isosorbide dinitrate"], "Outcome": ["ejection fraction", "exercise capacity", "rise of plasma norepinephrine", "plasma norepinephrine levels"], "Participant": ["patients with left ventricular dysfunction ."]}