The development of symptomatic heart failure is frequently preceded by a pre-clinical period of structural remodeling in the heart. The remodeling process driving this transition, however, remains poorly understood. The investigators hypothesize that imaging the diffusion of water in the heart with MRI will allow its microstructure to be resolved. The investigators further hypothesize that the characterization of microstructural changes in the heart will help elucidate the pathogenesis of heart failure and the transition from a compensated to a decompensated state. Patients with recent myocardial infarcts and left ventricular hypertrophy, who are at risk for the development of heart failure, will be enrolled. The participants will undergo serial diffusion tensor MRI (DTI) imaging of the heart to characterize changes in myocardial microstructure over time.

Inclusion Criteria:

• Healthy adults with no history of hypertension, diabetes or heart disease
• Patients with ST Elevation MI within last 6-10 weeks who are angina free, and have been seen by a cardiologist since discharge
• Patients with episode of heart failure within last 12 months and left ventricular hypertrophy, documented by echocardiogram or MRI.

Exclusion Criteria:

1. Presence of metallic foreign bodies/objects
2. Selected medical devices and implants
3. Pacemakers, implantable defibrillators, life vests
4. Coronary artery stent within last 6 weeks (unless the stent is a MRI-inert chromium-cobalt stent)
5. Known untreated ventricular arrhythmia such as sustained ventricular tachycardia within last 12 months
6. Atrial fibrillation that is not well rate controlled (heart rate >125)
7. Unstable angina within last 2 months that has not been fully evaluated by a cardiologist
8. Syncope within last 6 weeks
9. Hemodynamic instability (Systolic BP less than 100 or greater than 180)
10. Decompensated heart failure (inability to lie flat and perform a breath-hold).
11. Glomerular filtration rate (GFR) < 60 for those receiving gadolinium.
12. Labile GFR that is not stable/similar on last 2 measurements (for those receiving gadolinium).
13. Patients with GFR < 20 or on any form of dialysis.
14. Infiltrative cardiomyopathy (amyloid, sarcoid, hemachromatosis)
15. Recent surgery (within the last 3 months)
16. Prior stroke with large residual deficit
17. Presence of liver or respiratory failure
18. Pregnancy and nursing mothers
19. Claustrophobia
20. Known seizure disorder

IPD will not be shared