Table 2.

Annotation scheme, definitions and examples.

Classes	Description	Examples
Causes or risk factors	Merges two overlapped subclasses: causes and risk factors, where causes refer to concepts or terms that can directly cause heart failure and risk factors are those factors associated with an increased risk of heart failure.	In industrialized countries, coronary artery disease (CAD) has become the predominant cause in men and women and is responsible for 60-75% of cause of heart failure. Hypertension contributes to the development of heart failure in 75% of patients.
Signs or symptoms	Groups medical signs and symptoms. In addition it includes the physical examination for which would usually result signs or symptoms.	The cardinal symptoms of heart failure are fatigue and shortness of breath. Nocturnal cough is a common manifestation of this process and a frequently overlooked symptom of heart failure.
Diagnostic tests or results	Includes phrases that describe procedures, panels, and measures that are done to a patient or a body fluid or sample in order to discover, rule out, or find more information about a medical problem.	A routine 12-lead ECG is recommended. A chest X-ray provides useful information about cardiac size and shape.
Treatment	Includes phrases that describe procedures, interventions, and substances given to a patient in an effort to resolve a medical problem.	Dietary restriction of sodium (2-3 g daily) is recommended in all patients with the clinical syndrome of heart failure and either preserved or depressed ejection fraction. Diuretics are the only pharmacologic agents that can adequately control fluid retention in advanced heart failure.