Crochetage sign

Notch near the apex of the R wave of inferior leads seen in a large proportion of patients with an ostium secundum atrial septal defect (ASD), the most common form of ASD

Inferior leads demonstrating Crochetage sign. Source: BMJ
  • First described in 1958 by Toscano et al, the electrophysiological mechanism behind this ECG change remains unknown
  • A 1996 retrospective case study observed this pattern in at least one inferior lead of 73% of patients with a secundum ASD, and 36% of patients with ventricular septal defect (VSD), compared with 7% of the general population
  • Specificity for the diagnosis of ASD increased to 92-100% when associated with an incomplete RBBB pattern, or when present in all three inferior leads
  • In ASD, the incidence of Crochetage sign increases with larger anatomic defect or greater left-to-right shunt
  • A 2018 case control study found 28% of patients with ASD had this characteristic R wave notching in all three inferior leads compared to just 2% of age matched controls

ECG features of secundum ASD


ECG Examples of Crochetage sign

Example 1
Sarma A. Crochetage sign. IJCCM
  • Right axis deviation
  • Incomplete RBBB pattern
  • Crochetage sign in leads II, III and aVF

This patient was found to have a 20mm ostium secundum ASD. There was resolution of crochetage sign following operative repair


Example 2
  • Right axis deviation
  • Crochetage sign in leads II, III and aVF

References


Advanced Reading

Online

Textbooks


LITFL Further Reading

ECG LIBRARY 700

ECG LIBRARY

Electrocardiogram

MBBS (UWA) CCPU Emergency Medicine Advanced Trainee based in Melbourne, Australia. Co-author of the LITFL ECG Library. Likes Ultrasound, Echo, ECGs, and anything and everything with caffeine. Part of the 2021 ANZCEN Clinician Educator Incubator Programme | @rob_buttner | ECG Library |

Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

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