Patient description: The patient is a 25-year-old man with type 1 diabetes confirmed with molecular analysis 7 years ago. He presents to the clinic with shortness of breath and fatigue during activities. He claims mild dyspnea after climbing 3 floors, no dyspnea at rest and no angina (New York Heart Association class 2). He is diagnosed with cardiomyopathy that will be treated with ACE inhibitors and Beta blockers. His takes 70/30 Insulin and vitamin D supplements. His past medical history is not significant for any other medical issues. His family history is positive for DM type 1 in his uncle and his grandfather. His lab study is as bellow: FBS: 100 mg/dl HbA1c: 6.5% Cholesterol: 190 mg/dl TG: 140 mg/dl LDL: 125 mg/dl HDL: 40 mg/dl

Clinical trial eligibility criteria: eligible ages (years): 50.0-999.0,  Heart Failure Age ≥ 50 years 2. Symptoms of dyspnea (NYHA class II-IV) without evidence of a non-cardiac or ischemic explanation for dyspnea 3. Ejection fraction (EF) ≥ 50% as determined on imaging study within 12 months of enrollment with no change in clinical status suggesting potential for deterioration in systolic function 4. Stable medical therapy for 30 days as defined by No addition or removal of ACE, Angiotensin receptor blockers (ARBs), beta-blockers, calcium channel blockers (CCBs) or aldosterone antagonists No change in dosage of ACE, ARBs, beta-blockers,CCBs or aldosterone antagonists of more than 100% 5. One of the following within the last 12 months Previous hospitalization for heart failure (HF) with radiographic evidence of pulmonary congestion (pulmonary venous hypertension, vascular congestion, interstitial edema, pleural effusion) or Catheterization documented elevated filling pressures at rest (LVEDP≥15 or PCWP≥20) or with exercise (PCWP≥25) or Elevated NT-proBNP (> 400 pg/ml) or BNP (> 200 pg/ml) or Echo evidence of diastolic dysfunction / elevated filling pressures (at least two) E/A > 1.5 + decrease in E/A of > 0.5 with valsalva Deceleration time ≤ 140 ms Pulmonary vein velocity in systole < diastole (PVs<PVd)sinus rhythm) E/e'≥15 Left atrial enlargement (≥ moderate) Pulmonary artery systolic pressure > 40 mmHg Evidence of left ventricular hypertrophy LV mass/BSA ≥ 96 (♀) or ≥ 116 (♂) g/m2 Relative wall thickness ≥ 0.43 (♂ or ♀) [(IVS+PW)/LVEDD] Posterior wall thickness ≥ 0.9 (♀) or 1.0 (♂) cm 6. No chronic nitrate therapy or infrequent (≤ 1x week) use of intermittent sublingual nitroglycerin within last 3 months 7. Ambulatory (not wheelchair / scooter / walker / cane dependent) 8. HF is the primary factor limiting activity as indicated by answering # 2 to the following question: My ability to be active is most limited by: 1. Joint, foot, leg, hip or back pain 2. Shortness of breath and/or fatigue and/or chest pain 3. Unsteadiness or dizziness 4. Lifestyle, weather, or I just don't like to be active 9. Body size allows wearing of the accelerometer belt as confirmed by ability to comfortably fasten the test belt provided for the screening process (belt designed to fit persons with BMI 20-40 Kg/m2 but belt may fit some persons outside this range) 10. Willingness to wear the accelerometer belt for the duration of the trial 11. Willingness to provide informed consent  Recent (< 3 months) hospitalization for HF 2. Hemoglobin < 8.0 g/dl 3. Glomerular filtration rate < 20 ml/min/1.73 m2 on most recent clinical laboratories 4. SBP < 110 mmHg or > 180 mmHg at consent 5. Diastolic blood pressure < 40 mmHg or > 100 mmHg at consent 6. Resting HR > 110 bpm at consent 7. Previous adverse reaction to nitrates necessitating withdrawal of therapy 8. Chronic therapy with phosphodiesterase type-5 inhibitors (intermittent use of phosphodiesterase type-5 inhibitors for erectile dysfunction is allowable if the patient is willing to hold for the duration of the trial) 9. Regularly (> 1x per week) swims or does water aerobics 10. Significant COPD thought to contribute to dyspnea 11. Ischemia thought to contribute to dyspnea 12. Documentation of previous EF < 50% 13. Acute coronary syndrome within 3 months defined by electrocardiographic changes and biomarkers of myocardial necrosis (e.g. troponin) in an appropriate clinical setting (chest discomfort or anginal equivalent) 14. Percutaneous coronary intervention, coronary artery bypass grafting or new biventricular pacing within past 3 months 15. Primary hypertrophic cardiomyopathy 16. Infiltrative cardiomyopathy (amyloid) 17. Constrictive pericarditis or tamponade 18. Active myocarditis 19. Complex congenital heart disease 20. Active collagen vascular disease 21. More than mild aortic or mitral stenosis 22. Intrinsic (prolapse, rheumatic) valve disease with moderate to severe or severe mitral, tricuspid or aortic regurgitation 23. Acute or chronic severe liver disease as evidenced by any of the following: encephalopathy, variceal bleeding, INR > 1.7 in the absence of anticoagulation treatment 24. Terminal illness (other than HF) with expected survival of less than 1 year 25. Enrollment or planned enrollment in another therapeutic clinical trial in the next 3 months 26. Inability to comply with planned study procedures 27. Pregnant women