From ab2516826c4b3492f1246db978791207ad7f66d7 Mon Sep 17 00:00:00 2001
From: Stefan Appelhoff <stefan.appelhoff@mailbox.org>
Date: Mon, 23 Sep 2024 22:33:23 +0200
Subject: [PATCH] DOC: clean up ECG ICA docstrs (#12866)

---
 mne/preprocessing/ecg.py |  8 +++-----
 mne/preprocessing/ica.py | 13 ++++++-------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/mne/preprocessing/ecg.py b/mne/preprocessing/ecg.py
index 1c808867312..d8b220ed8ee 100644
--- a/mne/preprocessing/ecg.py
+++ b/mne/preprocessing/ecg.py
@@ -185,8 +185,8 @@ def find_ecg_events(
     %(filter_length_ecg)s
     return_ecg : bool
         Return the ECG data. This is especially useful if no ECG channel
-        is present in the input data, so one will be synthesized. Defaults to
-        ``False``.
+        is present in the input data, so one will be synthesized (only works if MEG
+        channels are present in the data). Defaults to ``False``.
     %(reject_by_annotation_all)s
 
         .. versionadded:: 0.18
@@ -325,8 +325,6 @@ def _get_ecg_channel_index(ch_name, inst):
 
     if len(ecg_idx) == 0:
         return None
-        # raise RuntimeError('No ECG channel found. Please specify ch_name '
-        #                    'parameter e.g. MEG 1531')
 
     if len(ecg_idx) > 1:
         warn(
@@ -487,7 +485,7 @@ def _make_ecg(inst, start, stop, reject_by_annotation=False, verbose=None):
     """Create ECG signal from cross channel average."""
     if not any(c in inst for c in ["mag", "grad"]):
         raise ValueError(
-            "Generating an artificial ECG channel can only be done for MEG data"
+            "Generating an artificial ECG channel can only be done for MEG data."
         )
     for ch in ["mag", "grad"]:
         if ch in inst:
diff --git a/mne/preprocessing/ica.py b/mne/preprocessing/ica.py
index d1b0e1b0456..d00d854fb4d 100644
--- a/mne/preprocessing/ica.py
+++ b/mne/preprocessing/ica.py
@@ -1616,17 +1616,16 @@ def find_bads_ecg(
         Cross-trial phase statistics :footcite:`DammersEtAl2008` or Pearson
         correlation can be used for detection.
 
-        .. note:: If no ECG channel is available, routine attempts to create
-                  an artificial ECG based on cross-channel averaging.
+        .. note:: If no ECG channel is available, an artificial ECG channel will be
+                  created based on cross-channel averaging of ``"mag"`` or ``"grad"``
+                  channels. If neither of these channel types are available in
+                  ``inst``, artificial ECG channel creation is impossible.
 
         Parameters
         ----------
         inst : instance of Raw, Epochs or Evoked
             Object to compute sources from.
-        ch_name : str
-            The name of the channel to use for ECG peak detection.
-            The argument is mandatory if the dataset contains no ECG
-            channels.
+        %(ch_name_ecg)s
         threshold : float | 'auto'
             Value above which a feature is classified as outlier. See Notes.
 
@@ -1696,7 +1695,7 @@ def find_bads_ecg(
         idx_ecg = _get_ecg_channel_index(ch_name, inst)
 
         if idx_ecg is None:
-            ecg, times = _make_ecg(
+            ecg, _ = _make_ecg(
                 inst, start, stop, reject_by_annotation=reject_by_annotation
             )
         else: