Intervention: Metoprolol Succinate
Trial phase: Phase 4
SMILES: COCCc1ccc(OCC(O)CNC(C)C)cc1.COCCc1ccc(OCC(O)CNC(C)C)cc1.O=C(O)CCC(=O)O
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 56
Group description: Idiopathic dilated cardiomyopathy patients randomized to metoprolol succinate titrated to a goal of 200 mg by mouth daily for 18 months

Metoprolol succinate
Eligibility criteria:
Inclusion Criteria:

Idiopathic dilated cardiomyopathy with New York Heart Association Class II-IV symptoms
No evidence of coronary artery disease by angiography within 2 years of randomization
If female, patient is (a) surgically sterile or (b) practices an accepted method of birth control and has negative serum pregnancy test
Patient has been on other conventional cardiac heart failure(CHF) therapy at least 3 weeks prior to baseline assessments (includes angiotensin converting enzyme inhibitors, digoxin, diuretics, and/or vasodilators)
Patient has left ventricular ejection fraction < 40% by radionuclide ventriculography within 60 days of randomization
Patient must demonstrate mental and physical ability and willingness to follow all study-specific instructions
Patient must voluntarily sign Institutional Review Board (IRB)-approved informed consent form prior to any study-specific procedure

Exclusion Criteria:

Patient has heart failure due to or associated with uncorrected primary valvular disease, uncorrected thyroid disease, obstructive/hypertrophic cardiomyopathy, pericardial disease, amyloidosis, active myocarditis, or malfunctioning artificial heart valve.
Patient is actively on heart transplant list or anticipated to be within 6 months of randomization

Patient is receiving any of the following medicines:

Calcium channel blockers
Theophylline
Tricyclic antidepressants
Monoamine oxidase inhibitors
β-agonists
β-adrenergic blocking agent (oral)
Any investigational cardiovascular medication or involvement in another investigational trial
Flecainide, encainide, propafenone, sotalol, disopyramide, or amiodarone
Patient has a contraindication to β-blockade (eg asthma)
Patient has another life-threatening disease with life expectancy < 2 years due to other illness
Patient has active hepatic, renal, hematologic, gastrointestinal, immunologic, endocrine, metabolic, or central nervous system disease which may adversely affect the safety and efficacy of the study drug or life span of the patient
Unstable decompensated heart failure (evidence of hypoperfusion, acute pulmonary edema, or hypotension with SBP < 80 mm Hg)
Patient is actively abusing ethanol or illicit drugs within 3 months of randomization
Patient has an automatic implantable cardiac defibrillator that has fired within 3 months of randomization
Patient has an asymptomatic waking, resting heart rate < 50 bpm or symptomatic bradycardia < 60 bpm.
Patient has uncontrolled insulin-dependent diabetes mellitus with a history of frequent hypoglycemia episodes
Patient has a high degree atrioventricular block (Mobitz Type II or complete heart block)
Patient is unable to tolerate magnetic resonance imaging procedures
Patient has demonstrated non-compliance with previous medical regimens