Health Equity and Access for Returning Troops and Servicemembers Act or the HEARTS Act This bill extends TRICARE eligibility to certain former members of the Armed Forces regardless of whether they enroll (as required under current law) in Medicare's supplementary medical insurance program. Specifically, the bill applies to former members who are: (1) younger than 65 years of age, (2) medically retired from the Armed Forces, and (3) entitled to Medicare hospital insurance benefits on the basis of their former entitlement to disability insurance benefits under the Social Security Act. Furthermore, these former members shall not be subject to late-enrollment penalties under Medicare's supplemental medical insurance program. The Department of Defense must coordinate with the Department of Health and Human Services to: (1) identify former members to which the bill applies, (2) counsel those former members on the effects of declining to enroll in Medicare's supplemental medical insurance program, and (3) report to Congress on specified issues related to the bill's implementation.