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: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. 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:

The role of natriuretic peptides as biomarkers for guiding the management of chronic heart failure. The current standard treatment of chronic heart failure (HF) is based on clinical judgment, with the goal of achieving the maximally tolerated therapeutic program. The complexity of this approach may contribute to the well-established treatment gaps that exist in HF management; consequently, the risks for morbidity and mortality in this population remain extremely high. Alternative means are needed to improve the outcomes of patients with HF. Natriuretic peptides are biological markers for HF disease--its presence, severity, and prognosis--and show unique interactions with therapeutics known to have benefit in HF. Accordingly, interest has recently developed in "biomarker-guided" care for HF. This approach involves applying these assays to identify patients in need of therapy intensification and to provide an objective "monitor" of disease status. This review examines the biology of natriuretic peptides, discusses the rationale for their use in HF, and details the aggregate experience gained thus far in biomarker-guided care.
{"Chemical": []}