Heart disease includes many types, such as chronic heart failure, acute myocardial infarction, rheumatic heart disease, arrhythmias, and more. If it is chronic heart failure with NYHA class II, it means the patient's physical activity is slightly limited, there are no symptoms at rest, but symptoms of heart failure may appear under normal activities. How serious NYHA class II chronic heart failure is needs to be analyzed based on the specific issue because this classification is quite subjective. Other factors, such as the patient’s echocardiographic ejection fraction, the end-diastolic diameter of the left ventricle, the underlying disease of the patient, the value of B-type natriuretic peptides, etc., need to be considered in a comprehensive analysis to judge the severity of the patient's condition.