Wednesday, January 8, 2020

A young woman with epigastric pain. ECG Crochetage sign? What is the significance?

A former resident texted me this ECG, done for epigastric pain in an 18 year old.  The pain resolved immediately with treatment for acid reflux, and in the clinician's opinion was clearly GI in origin, but he wanted to know what the strange waves in the QRS were:
See the unusual notching in II, III, aVF, and V2-V4.
I had no idea what they were.  
They reminded me of the Delayed Activation Wave associated with circumflex acute MI.
See this case:
But they are clearly different from this.

I put it on Facebook EKG club and this is the response:

No one knew for certain what that was, but Ken Grauer suspected artifact (due to lead placement over an artery) or a Crochetage sign, which is strongly associated with atrial septal defect.  

I looked up Crochetage sign and it sure does look like it!

You can always rely on Ken.

I told my former resident:
The latter (Crochetage) is important because it is seen in atrial septal defect.  I not sure the cardiologist will know this.  You should make certain she gets an echo specifically looking for ASD (especially if still present on a repeat ECG).  Let the referral cardiologist know.  He will notify the patient but, unfortunately,  because she will follow up in a different system, he will not have follow up.

Crochetage sign

You can see many more images of the Crochetage sign here.

See the 5 articles below.

Crochetage”(notch) on R wave in inferior limb leads: a new independent electrocardiographic sign of atrial septal defect

'Crochetage'sign on ECG in secundum ASD: clinical significance

The Significance of Crochetage on the R wave of an Electrocardiogram for the Early Diagnosis of Pediatric Secundum Atrial Septal Defect

Electrocardiographic findings in patients with cryptogenic ischemic stroke and patent foramen ovale


An Electrocardiographic Criterion for Diagnosis of Patent Foramen Ovale Associated With Ischemic Stroke

MY Comment by KEN GRAUER, MD (1/8/2020):
My appreciation to Dr. Stephen Smith for the “callout” to me on this case. I’ll add the following to his comments:
  • For clarity — I’ve reproduced and labeled the ECG in this case in Figure-1.
  • I would LOVE to know whether further evaluation was done to determine IF this patient had a previously undetected ASD!
  • The reasons that I initially suspected that the notching might be artifact are: i) Although crochetage on ECG is described as being seen primarily (often exclusively) in the inferior leads (WHITE arrows in Figure-1) — at least 4 additional leads here show notching within the QRS complex (BLUE arrows) — with this notching in lead V3 looking especially unusual (ie, unphysiologic); and, ii) There is clear evidence of artifact elsewhere on this tracing! (within the BLUE circles in leads aVR and V4 — with this artifactual deflection also being seen in simultaneously occurring leads aVL & aVF; and in V5 & V6). NOTE: A special kind of artifact has been described in which geometric lines (ie, as in lead V3) are temporally related to the QRS complex, because the electrode lead is in contact with a pulsating artery. That said — against this being artifact, is that this notching is not seen in all leads in Figure-1. 

Figure-1: The ECG shown in this case. A common sampling of “crochetage” tools is seen at the bottom (See text).

Dr. Smith has added links to key references regarding the Crochetage Sign in ECG interpretation.
  • The term “crochetage” is French. The infinitive of the verb that means “to crochet” ( = crocheter in French) — and the initial literature on this subject came out of Paris in 1996 by Heller et al in JACC (The first reference provided by Dr. Smith above — and it looks to me like all authors except Joseph Heller in this 1996 article were French). NOTE: The term, “crochetage” in French is the noun ( = the act of crocheting) — but this word has also been translated into English as meaning, “lock-picking” (because lock-pickers often use a similar array of tools in their trade).
  • The study by Heller et al is noteworthy, because their conclusions hold true today, more than 20 years later. Their study was based on evaluation of 1,560 older children and adults — in which they searched for a Crochetage Pattern ( = a notch on the upstroke of the R wave in one or more of the inferior leads). Five different types of valvular heart disease were present among subjects in their study (about 1/3 had secundum atrial septal defect) — and about 1/3 of the patients were normal subjects.
  • There was a high (but far-from-perfect) correlation between the presence of crochetage in the patients with ASD (Atrial Septal Defect). Specificity for ASD greatly increased (≥92% in their study) when crochetage was seen in all 3 of the inferior leads  and/or when incomplete RBBB (IRBBB) was also present.
  • I don’t believe the mechanism for the crochetage “notch” on ECG with ASD is known. What has been observed — is that presence of crochetage showed good correlation to shunt severity. Of interest — early disappearance of crochetage was observed in ~1/3 of patients following surgical correction (though the IRBBB pattern persisted).

Finally — it should be pointed out that incomplete RBBB is a common ECG finding in patients with ASD. Typically with IRBBB — one sees a QRS complex that is not prolonged (ie, less than 0.11 second) + an rsR’ (or its equivalent) in lead V1 + terminal S waves in both leads I and V6.
  • In Figure-1 — the QRS is clearly not prolonged — and, there are narrow terminal s waves in both leads I and V6 (albeit the terminal s in V6 is tiny). Although we do not see a terminal R’ in lead V1 of Figure-1 — We do see a notch in the upstroke of the S wave in this lead. Another French term = forme fruste” IRBBB has been used to describe this pattern (ie, a “frustrated” form of IRBBB that falls short of full criteria — but which has similar clinical implications) — and that is how I would describe what we see in ECG #1. That said — I have NO idea why this S wave notch persists in lead V3, nor why we also see a notch at the peak of the R wave in lead V4 (BLUE arrows).

Our THANKS to Dr. Smith for presenting this case.
  • STEVE — Is there any way to get follow-up on this case?

ADDENDUM (5/8/2021): Although descriptions vary in the literature that I've seen — true crochetage is said to occur on the upstroke of the R wave in inferior leads, occurring within the first 80 msec. of the QRS. So in today's ECG — the notch (WHITE arrow) occurs near the apex of the QRS in lead III — which is consistent with crochetage. But as per the WHITE arrows in leads II and aVF — the notch occurs on the downstroke (instead of the upstroke) of the R wave in these leads. That said — many of the examples that I've seen posted on-line are also not on the "upstroke" of the R wave. 
  • BOTTOM Line: Listen extra carefully for signs of ASD (ie, fixed split S2) when you see an ECG similar to today's tracing — especially if incomplete RBBB (or its equivalent) is seen — and have a low threshold for getting an Echo if ASD is a consideration.


  1. Sad that follow up isn't possible, but that's part of it all I guess!

    1. It is unlikely we'll get followup, but I have asked for it!

  2. Steve and Ken...

    I think this sign is more consistent with crochetage though I would be reluctant to call it that unless it had a very classic appearance in ALL the inferior leads; a RBBB would make it even better. I do not think it has anything to do with electrode placement over an artery because the notch is located in the QRS and cardiac mechanical systole doesn't take place until the latter part of the ST segment and the T wave. A peripeheral pulse probably occurs even later than that. The calcium-induced calcium release which leads up to myofibril contraction doesn't occur until midway through Phase 2 (ST segment).

    If she was not aware of any history of secundum ASO defect then she should have a cardiological evaluation. Sometimes the patients ARE aware of these problems but you just have to drag it out of them. One of these days I'll tell you about my encounter with a young patient with a PDA during my very first night ever in the emergency department as an internal medicine resident.

    1. Thanks so much (as always!) for your insight Jerry. As I noted in the 3rd bullet of My Comment above — lack of similar notching at the same place in all 12 leads to me argued against artifact (despite other clear artifactual deflections on this tracing within the BLUE circles, and the simultaneously-obtained leads below them in Figure-1). I believe we agree that the diagnosis of an ASD secundum effect can’t be made on the basis of this ECG — but that further eval. is clearly indicated. THANKS again for your comment! — :)

  3. description of notch on R wave in the electrocardiogram of the patient with atrial septal defect was given by Alvarez et al in 1959.

  4. description of notch on R wave in the electrocardiogram of the patient with atrial septal defect was given by Alvarez et al in 1959.


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