diff --git a/.github/workflows/pr-review-merge-scheduler.yml b/.github/workflows/pr-review-merge-scheduler.yml
index e4d6b8737a..849ae8a9f1 100644
--- a/.github/workflows/pr-review-merge-scheduler.yml
+++ b/.github/workflows/pr-review-merge-scheduler.yml
@@ -73,7 +73,23 @@ on:
         default: ""
         type: string
   schedule:
-    - cron: "*/30 * * * *"
+    # scan-pr-queue's own repository-local heartbeat. org-queue-sweep below
+    # explicitly excludes ContextualWisdomLab/.github from its target list
+    # (a PR in THIS repository, including one editing the governance
+    # workflows themselves, is never covered by the org-wide sweep), so this
+    # is the only periodic fallback for this repository's own PR queue. It
+    # also plugs a real event-coverage gap shared by every repository:
+    # required checks such as Security Scan and SAST Semgrep have no
+    # workflow_run listener anywhere in this file, so a PR where either is
+    # the last required check to go green has no event-driven re-wake at
+    # all. Offset by 30 minutes from org-queue-sweep's "0 * * * *" tick so
+    # the two heartbeats do not collide. Lengthened from */30 to hourly for
+    # the same Actions-capacity reason, and by the same lever, as the
+    # org-queue-sweep hourly cadence below (see
+    # docs/doctoring/actions-queue-saturation-hourly-sweep.md, #1630) — do
+    # NOT remove it outright; that would leave this repository's own queue
+    # with zero fallback heartbeat.
+    - cron: "30 * * * *"
     # Hourly org-wide sweep cadence for the org-queue-sweep job below. Target
     # repositories only receive scheduler runs on PR events, review/security
     # workflow completion, and protected-branch pushes; a PR whose approval or
diff --git a/tests/test_actions_queue_saturation_scheduler_cadence.py b/tests/test_actions_queue_saturation_scheduler_cadence.py
index fbf8f45547..fa5ce36370 100644
--- a/tests/test_actions_queue_saturation_scheduler_cadence.py
+++ b/tests/test_actions_queue_saturation_scheduler_cadence.py
@@ -31,3 +31,23 @@ def test_repository_scheduler_keeps_event_driven_wakes() -> None:
     assert "pull_request_review:" in workflow
     assert "workflow_run:" in workflow
     assert "repository_dispatch:" in workflow
+
+
+def test_scan_pr_queue_heartbeat_is_hourly_and_offset_not_removed() -> None:
+    """scan-pr-queue's own repository-local heartbeat must not be dropped.
+
+    org-queue-sweep excludes ContextualWisdomLab/.github from its target
+    list by name, so scan-pr-queue's own cron is the sole periodic fallback
+    for this repository's PR queue (and for any required check, such as
+    Security Scan or SAST Semgrep, with no workflow_run listener anywhere in
+    this file). It must be lengthened to hourly for the same capacity reason
+    as org-queue-sweep, not deleted, and offset from org-queue-sweep's
+    "0 * * * *" tick so the two heartbeats do not collide.
+    """
+    workflow = WORKFLOW.read_text(encoding="utf-8")
+    assert '- cron: "30 * * * *"' in workflow
+    assert '*/30 * * * *' not in workflow
+    schedule_block = workflow.split("  schedule:", 1)[1].split(
+        "  repository_dispatch:", 1
+    )[0]
+    assert schedule_block.count('- cron:') == 2
diff --git a/tests/test_required_workflow_queue_contract.py b/tests/test_required_workflow_queue_contract.py
index 056e47a678..a1cb4d77fe 100644
--- a/tests/test_required_workflow_queue_contract.py
+++ b/tests/test_required_workflow_queue_contract.py
@@ -988,8 +988,8 @@ def test_org_queue_sweep_covers_target_repositories_on_a_heartbeat() -> None:
     visible reason when it cannot mutate sibling repositories. The sweep runs
     hourly so an approval that lands after a PR's last event is
     auto-updated/merged promptly instead of idling indefinitely. Its cron has a
-    distinct concurrency key from the separate 30-minute scan, and the job has
-    enough runtime headroom to finish a complete organization walk.
+    distinct concurrency key from the separate scan-pr-queue heartbeat, and the
+    job has enough runtime headroom to finish a complete organization walk.
     """
     workflow = workflow_text("pr-review-merge-scheduler.yml")