Practices rarely switch systems on impulse. Among physicians who said their practice or employer changed EHRs in 2023, the most common reasons were that the old system could not exchange information with other EHRs (45%) and a plan to merge inpatient and outpatient systems (43%), according to Medscape’s 2023 Physicians and Electronic Health Records Report, published November 29, 2023, and based on 1,476 respondents. Those are sound reasons to move. They do not shorten the billing clean-up that follows, and this guide covers where cardiology claims tend to stall.

Why cardiology billing during an EHR migration carries extra risk

Three features set the specialty apart. Diagnostic services split into professional and technical pieces, and some into their own component codes. Several services are billed on a calendar instead of at the visit. And a single wrong code mapping repeats on every claim for that service until someone notices.

Medicare sets the outer deadline. Under 42 CFR 424.44, fee-for-service claims for services furnished on or after January 1, 2010 must be filed within one calendar year of the date of service, with narrow exceptions such as administrative error. Commercial contracts set their own limits, which can be shorter. Check each one rather than assuming twelve months.

Where charges get lost or miscoded

Test and imaging code mapping

Echocardiography shows the problem clearly. CPT 93306, the complete transthoracic echo, already includes spectral and color flow Doppler. The American Society of Echocardiography’s coding FAQs, written when 93306 replaced the older three-code echo set in 2009, state that 93320 and 93325 should not be reported with it. If the new charge master lets a technologist or coder add those Doppler lines anyway, the claim carries bundled services that payers can deny.

Stress testing needs a different check. CPT 93015 reports supervision, tracing, and interpretation with report in one code. Codes 93016, 93017 and 93018 report those pieces separately, which fits a setting where a hospital owns the treadmill, one cardiologist supervises and another reads the tracing. The American Medical Association’s CPT Assistant tells each physician to report only the components that physician provided. Because the split is built into the codes, a template that appends modifier 26 or TC to every diagnostic line will misdescribe these tests.

Services billed on a clock

Remote pacemaker monitoring is the clearest example. Abbott’s cardiac device monitoring quick reference guide lists 93294 (professional) and 93296 (technical) as reportable no more than once every 90 days, and not when the monitoring period is shorter than 30 days. Because the limit is counted in days, the date of the last billed service has to travel with the patient’s record. If it does not, the practice either bills early and takes a frequency denial or lets a window pass unbilled.

Global periods create the same exposure. The Medicare Physician Fee Schedule assigns a 90-day global period to pacemaker implant codes such as 33208, so routine post-operative care by the implanting physician is paid inside the procedure. Without the implant date, staff cannot tell a bundled wound check from a visit that can be billed.

Payer connections that fail quietly

A new billing module often puts a new submitter or vendor between the practice and its payers. The CMS Medicare Claims Processing Manual (chapter 24, section 30.2) calls for a new EDI enrollment form when a provider moves from direct submission to a clearinghouse or from one billing agent to another. Medicare contractors process vendor changes on their own forms; First Coast Service Options, for example, offers a “vendor change only” box for a practice that changes software and nothing else.

A missed enrollment also puts the filing deadline into play. First Coast’s Medicare guidance warns that rejected and unprocessable claims affect timely filing, which makes the clearinghouse rejection report required daily reading for the first weeks. Electronic remittance and funds-transfer enrollments deserve the same attention. Several commercial payers direct providers to CAQH EnrollHub for EFT registration, and a payment that arrives without a matching 835 remittance file has to be posted by hand.

Open authorizations need a home too. Carry each authorization number, approved units and expiration date into the new system as structured fields rather than a scanned note, so claim edits can read them.

Moving the data: what to ask the old vendor for

Federal certification rules give practices some leverage. Under 45 CFR 170.315(b)(10), certified health IT developers had to make an electronic health information export available by December 31, 2023, covering a single patient or an entire patient population. ONC’s Cures Act rulemaking framed the population export as a way for providers to switch health IT systems. ONC’s own guidance, in its HealthIT.gov article “Getting Ready for EHI Export: A Quick Guide,” adds a caution: a population export can require action or support from the developer, so it is not a one-click task.

Do not assume the export carries billing history. Ask the vendor in writing whether open balances, payment postings, adjustment codes and charge history are included, and in what format. Keep the old system available in read-only mode until the last pre-migration balance is resolved, because underpayment appeals on older dates of service still need the original charge detail.

A cutover plan that protects cash flow

Evidence on how much revenue a migration costs is mixed, and much of it covers first-time adoption at academic centers rather than a switch between vendors. A Weill Cornell analysis (International Journal of Medical Informatics, May 2010, volume 79, issue 7) found that providers added 9 visits per month after adopting Epic’s ambulatory EHR. A comparison of two departments in the American Journal of Orthopedics (May/June 2017) found no significant change in visit volume. Neither was cardiology-specific, and both looked at visits, charges or coding levels rather than payer rejections. Treat them as a reason not to assume a fixed percentage loss, and plan from your own data.

The Healthcare Financial Management Association’s MAP Keys define 29 revenue cycle measures in five groups, among them clean claim rate and days in A/R. Pull the six months before go-live to set your practice’s own baseline, then compare weekly by code family (echo, stress, device checks, procedures) instead of one practice-wide average. A mapping error in one family can hide inside a healthy overall number.

Key checks before go-live

Cardiology billing during an EHR migration comes down to a short list that can be verified in advance. Confirm that 93306 cannot be billed with Doppler add-on codes and that the 93015 to 93018 family has no automatic modifiers. Transfer the last billed date for every 90-day remote monitoring service and the implant date for every open 90-day global period. File new EDI enrollments where the CMS manual calls for them, since the one-year limit in 42 CFR 424.44 applies whether or not the new system is working yet. Get the export scope for open balances in writing. Track clean claim rate and days in A/R by service line against the six months before go-live.