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:

Comparison of the efficacy and safety of esmolol , a short-acting beta blocker , with placebo in the treatment of supraventricular tachyarrhythmias . The Esmolol vs Placebo Multicenter Study Group . The efficacy and safety of esmolol , a short-acting intravenous beta-adrenergic-blocking agent , and placebo were compared in patients with supraventricular tachyarrhythmias ( heart rate greater than 120 bpm ) in a multicenter , double-blind , partial-crossover study . Seventy-one patients were randomized to receive either esmolol ( n = 36 ) or placebo ( n = 35 ) as initial treatment . Therapeutic failures were crossed over to the other study medication . Therapeutic response was defined as greater than or equal to 20 % reduction in heart rate , heart rate less than 100 bpm , or conversion to normal sinus rhythm . The therapeutic response to esmolol during the initial treatment period ( 72 % ) was similar to that obtained when esmolol was given as a second agent . The average esmolol dosage producing a therapeutic response was 97.5 micrograms/kg/min . Four patients ( 6 % ) converted to normal sinus rhythm during esmolol infusion . In the majority of patients ( 80 % ) , therapeutic response was lost within 30 minutes following discontinuation of esmolol infusion , a finding indicative of rapid reversal of beta-adrenoceptor blockade . The most prevalent adverse effect during esmolol infusion was hypotension which occurred in eight patients ( 12 % ) . Hypotension and associated symptoms resolved within 30 minutes after discontinuation of esmolol infusion , which is consistent with the short duration of action of esmolol ( elimination half-life of 9.2 minutes ) .
{"Intervention": ["esmolol", "Placebo", "placebo", "Esmolol"], "Outcome": ["efficacy", "Hypotension and associated symptoms", "hypotension", "conversion to normal sinus rhythm", "The therapeutic response", "heart rate", "normal sinus rhythm", "adverse effect", "heart rate less than 100 bpm", "Therapeutic response", "safety", "therapeutic response"], "Participant": ["Seventy-one", "supraventricular tachyarrhythmias .", "supraventricular tachyarrhythmias"]}