Effects of Viagra on Heart Function in Patients With Heart Failure
Condition: Heart Failure; Left Ventricular Dysfunction
MeSH terms: Heart Failure; Ventricular Dysfunction; Ventricular Dysfunction, Left
Intervention: sildenafil; Placebo
Intervention description: Changes in left ventricular filling pressure 1 hour after the administration of a single oral dose of sildenafil 50 mg.; Changes in left ventricular filling pressure 1 hour after oral administration of placebo
Intervention MeSH terms: Sildenafil Citrate
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Enrollment: 10.0
Sex: All
Minimum age: 25 Years
Maximum age: 75 Years
Healthy volunteers: No
Keywords: heart failure, left sided; ventricular dysfunction; diastolic dysfunction; sildenafil

Summary:

      Sildenafil (Viagra) is known to reduce pulmonary hypertension. Heart failure patients also
      have pulmonary hypertension and several recent reports have shown that sildenafil leads to an
      improvement in their exercise capacity. In these studies sildenafil caused a reduction in the
      pulmonary and systemic vascular resistances, improved pulmonary gas diffusion and perhaps
      increased cardiac output. It is uncertain if left ventricular filling pressures are reduced
      and whether there is improvement in left ventricular relaxation. The investigators
      hypothesize that in heart failure patients the improvement in exercise capacity associated
      with sildenafil is related to a significant reduction in left ventricular filling pressures.
      The investigators propose to study 20 patients with stable but moderately symptomatic heart
      failure. The study design is a randomized cross-over trial of the administration of a single
      dose of sildenafil 50 mg or a matching placebo. Exercise capacity will be determined before
      and after the oral administration of sildenafil 50 mg or placebo. Left ventricular filling
      pressures will be assessed by Doppler echocardiography and the serum level of B-type
      natriuretic peptide (BNP is known to increase with higher left ventricular filling
      pressures). After an initial echocardiogram and performing a 6 minute walk test, the patient
      will then be given either sildenafil or a matching placebo in a randomized double-blind
      fashion. One hr later a blood sample for serum BNP, the echocardiogram and the 6 minute walk
      test will be repeated.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Adults with Class III congestive heart failure and impaired left ventricular systolic
             function.

          -  A prior BNP level ≥ 200 pg/mL.

          -  Previously documented systolic pulmonary artery pressure >40 mmHg.

          -  Clinically stable for a minimum of 6 weeks.

          -  Able to give informed consent,

        Exclusion Criteria:

          -  Unable to give informed consent.

          -  Currently taking nitrates.

          -  A HF exacerbation within the past 6 weeks.

          -  Co-morbid conditions that could limit their walking.

          -  Have a resting systolic blood pressure < 110 mmHg