G177 – Ventricular pacing and mapping
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
G177 is classified as a major invasive procedure. As such, it qualifies for after-hours procedure premiums. These premiums (E409, E410 for non-Emergency Department physicians, and E412, E413 for Emergency Department physicians) are applicable when the service is rendered on a non-elective basis or if an elective procedure is delayed by an intervening surgical emergency and commences during specified after-hours periods, as detailed on page of the Schedule.
When to Use
- Use G177 when performing ventricular mapping and pacing as part of a complex electrophysiology study or ablation procedure.
- Use G177 for ventricular tachycardia mapping procedures where intracardiac catheter placement and stimulation are required to identify the circuit.
Common Pitfalls
- Billing G177 alongside G176 for the same session is generally considered unbundling unless distinct, separate procedures are documented.
- Claiming after-hours premiums (E409-E413) for elective cases that were not delayed by an intervening surgical emergency will result in automatic rejection.
- Failing to append Z423 when using advanced nonfluoroscopic mapping systems or when the procedure duration exceeds four hours, as this is a separate billable add-on.
Billing Tips
- Always ensure the procedure start time is clearly recorded in the chart to justify the use of E409 or E410 premiums.
- If using an advanced 3D mapping system, ensure Z423 is submitted on the same claim to capture the additional complexity fee.
Effective: April 1, 2025
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Procedure
Diagnostic and Therapeutic Procedures
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