BELIEVE Study: Nesiritide and Post Myocardial Infarction Left Ventricular Modeling

During the 72 hours of intravenous (IV) nesiritide infusion, if the systolic blood pressure decreases to less than 90 mmHg for 5 minutes, the coronary care unit (CCU) sx will be notified and if the systolic blood pressure has not increased to > or equal to 90 mmHg within 45 minutes, the nesiritide infusion will be stopped. All patients will receive other medical therapy as determined appropriate by the physician except for angiotensin converting enzyme inhibitor (ACEI), which will be started 24 hours after IV nesiritide. Lisinopril will be started 24 hours after the start of IV nesiritide at an initial dose of 2.5 mg and to be titrated up by the participants' physician according to their clinical status. The window for the lisinopril doses would be +/- 1 hour.

Patients with any signs or symptoms of post revascularization ischemia will be discontinued from the study.

Blood for the measurement of renin, angiotensin II (Ang II), aldosterone (Aldo), endothelin (ET)-1, norepinephrine, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), cGMP, C reactive protein, tumor necrosis factor (TNF)-alpha, matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP)-2 will be drawn before the initiation of IV nesiritide, six hours into the infusion before the initiation of ACEI and just before completion of the 72 hour infusion. The window for the blood draw for the six hour time point would be +/- 1 hour and the 72 hour time point would be +/-1 hour or just prior to discharge but not less than 66 hours.

MUGA will be performed within 24 hours after the initiation of the IV nesiritide to assess systolic and diastolic volumes and LV ejection fraction (EF).

Follow up at 4 weeks:

All patients, whether they complete the entire 72 hours of the nesiritide infusion or not, will return 1 month later for a repeat MUGA and blood draw for the neurohumoral profiling and pregnancy test if required by nuclear cardiology. The visit window for the one month return would be 30 to 40 days.