
    low enrollment
  
['pulmonary hypertension', 'cardiac mri <40']
['carvedilol']

        Inclusion Criteria:

          1. Subjects will be eligible to participate in the study if all of the following
             conditions exist:

          2. Age > 18 years

          3. WHO category 1 pulmonary arterial hypertension (Dana Point 2008)

          4. WHO functional class II-III

          5. RVEF by cardiac MRI < 40%

          6. Mean pulmonary artery pressure > 40 mm Hg

          7. Stable on PAH-specific therapy as defined by no change in PAH-specific treatment and
             functional class in the past 3 months. Patient can be on either mono or combination
             PAH-specific therapy

        Exclusion Criteria:

          -  1. Subjects will be excluded from participation in the study if any of the following
             conditions exist: 2. Significant persistent bradycardia (resting heart rate < 60 bpm)
             without a permanent pacemaker 3. Second or third degree AV block without a permanent
             pacemaker 4. Significant sinus tachycardia (resting heart rate > 100 bpm) 5. Use of
             anti-arrhythmic drugs 6. Hypotension defined as systolic blood pressure < 100 mmHg at
             the time of enrollment 7. Significant illness in the past 30 days requiring
             hospitalization 8. Acute decompensated right heart failure within past 30 days 9.
             Known allergy or intolerance to carvedilol or other β blockers 10. Cardiac index < 2
             l/min/m2 or right atrial pressure > 15 mm Hg 11. Asthma
      