This is a Phase 3, prospective, open-label, multicenter study to assess the efficacy of NH002-enhanced echocardiography in subjects with suboptimal echocardiograms to opacify the left ventricular chamber and to improve the left ventricular endocardial border delineation compared with unenhanced echocardiography. The study also aims to investigate the safety and tolerability of NH002.

Inclusion Criteria:

1. 18 years of age or older
2. Ability to understand and the willingness to provide written informed consent
3. Having or suspected of having cardiac disease
4. Undergone a transthoracic echo within 30 days prior to NH002 dose administration, resulting in suboptimal LVEBD, as defined by 2 or more segments of 6 segments of the ventricular border that cannot be visualized reliably in any of the standard apical 4-, 2-, and 3-chamber views during the resting non-contrast ultrasound examination

Exclusion Criteria:

Subjects will be excluded from the study if one or more of the following exclusion criteria are applicable:

1. Any evidence of other severe or unstable cardiopulmonary and/or systemic hemodynamic conditions deemed unsuitable for the study by the investigator(s) prior to NH002 dose administration, including, but not limited to:

   1. ongoing or recent acute coronary syndrome within 6 months.
   2. uncontrolled serious ventricular arrhythmias.
   3. decompensated or inadequately controlled congestive heart failure (New York Heart Association Class IV).
   4. atrial fibrillation or current uncontrolled cardiac arrhythmias causing symptoms or hemodynamic compromise.
   5. uncontrolled hypertension (i.e., resting systolic blood pressure >200 mmHg or diastolic blood pressure >110 mmHg or arterial hypotension [defined as systolic blood pressure ≤ 90 mmHg]).
   6. acute aortic dissection.

2. Known or suspected hypersensitivity to one or more of the ingredients of NH002, perflutren, Definity®, or other echocardiographic contrast agents

3. Known or suspected hypersensitivity to polyethylene glycol, prior reactions to common polyethylene glycol-containing products such as colonoscopy bowel preparations, and certain laxatives (e.g., Miralax)

4. Received an investigational compound within 30 days before enrolling in the study

5. Received any contrast agent either intravascularly or orally within 48 hours prior to NH002 dose administration

6. Pregnant or lactating female. Exclude the possibility of pregnancy:

   1. testing on-site at the institution (serum or urine β-human chorionic gonadotropin) within 24 hours prior to the start of NH002 dose administration, and
   2. history of using an adequate and medically approved method of contraception to avoid pregnancy for at least 1 month prior to NH002 dose administration and willing to continue using the same method for the duration of the study, or
   3. surgical history (e.g., tubal ligation or hysterectomy), or
   4. postmenopausal with a minimum of 1 year without menses.

7. Serious medical or psychiatric illness/condition likely, in the judgment of the investigator, to interfere with compliance to protocol treatment/research