Angiotensin-Neprilysin Inhibition in Diastolic Dysfunction After AMI

Inclusion Criteria: 1. Documented ST segment elevation or non ST- myocardial infarction according to current guidelines 2. Complete revascularization 3. Age ≥50 years 4. LVEF ≥45% on echocardiography performed within 72 hours of the MI. 5. Diastolic dysfunction defined as: Ratio of early diastolic peak mitral inflow velocity (E) to early mitral annulus diastolic velocity (e') ratio \> 8 and at least moderate LA dilatation (LA volume index\>34 mL/m2). 6. Signed informed consent Exclusion Criteria: 1. Intolerance towards study medication 2. Permanent atrial fibrillation, 3. Known history of cardiomyopathy, 4. More than mild valvular heart disease, 5. Severe obstructive or restrictive pulmonary disease, 6. Inability to perform exercise testing, 7. Inadequate acoustic windows on echocardiography, 8. Ongoing treatment with an angiotensin converting enzyme inhibitor at randomization. 9. Class I indication for an angiotensin converting enzyme inhibitor 10. Symptomatic hypotension, a systolic blood pressure of less than 100 mm Hg at screening 11. An estimated glomerular filtration rate (eGFR) below 30 ml per minute per 1.73 m2 of body-surface area at any time, 12. A serum potassium level of more than 5.2 mmol per liter at screening, 13. A history of hereditary or idiopathic angioedema or unacceptable side effects during receipt of angiotensin converting enzyme inhibitor or angiotensin receptor blocker 14. Inability to provide informed consent 15. Concomitant use of drugs containing aliskiren in patients with diabetes mellitus. 16. Severe reduced liver function, biliary cirrhosis or cholestasis (Child-Pugh class C) 17. Pregnant or nursing(lactating) women(see section 8.2.1 for details) 18. Fertile women unless they are using a highly effective method of contraception(see section 8.2.2 for details)