HALO: A Single Arm Prospective Investigation of the SJM™ Masters HP™ 15mm Rotatable Mechanical Heart Valve

The study is a single arm, prospective, non-randomized, multi-center clinical investigation.

The objective of this study is to evaluate the safety and effectiveness of the 15mm MHV in
subjects five years or less of age with a diseased, damaged, or malfunctioning mitral heart
valve. The objective will be evaluated by assessing valve-related adverse events, subject
survival, subject growth, and echocardiogram assessment of hemodynamic function through the
five year follow-up visit as long as the valve remains implanted.

Inclusion Criteria:

1. Subject requires mitral valve replacement.*

*Subjects undergoing concomitant procedures (e.g. valve repair) are eligible for this
study other than those noted in the exclusion criteria.

2. Subject's legally authorized representative gives written consent to participate in
the clinical study.

3. Subject is willing and able to return for data collection and follow-up for the
duration of the clinical study.

Exclusion Criteria:

1. Subject is > 5 years of age.

2. Subject has a contraindication to anticoagulant/antiplatelet medication.

3. Subject has a prosthetic valve(s) at a site other than the mitral valve prior to the
study procedure.*

*Subjects who have undergone a previous Ross procedure of the pulmonary valve are
eligible for this study.

4. Subject requires concomitant replacement of the tricuspid, pulmonary, or aortic valve.

5. Subject has active endocarditis.

6. Subject has active myocarditis.

7. Subject has an acute preoperative neurological deficit that has not returned to
baseline or stabilized ≥ 30 days prior to the study procedure.

8. Subject has had an acute cardiac adverse event that has not returned to baseline or
stabilized ≥ 48 hours prior to the study procedure.

9. Subject has a non-cardiac illness resulting in a life expectancy of < 1 year.

10. Subject has a known requirement for additional cardiac surgery within 12 months after
the study procedure.

11. Subject has been previously enrolled and implanted in this study.

12. Subject is participating in another study for an investigational drug and/or device.

13. Subject has any other medical condition that in the opinion of the Investigator will
interfere with the study results.

Eligibility criteria applicable to original IDE cohort.