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Microscopic Topography of Atrioventricular Conduction System–A Feature of Potential Clinical Significance
Author(s) -
Sahni Daisy,
Randhawa Arpan,
Gupta Tulika,
Aggarwal Anjali
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb1
Subject(s) - medicine , tricuspid valve , anatomy , electrical conduction system of the heart , atrioventricular node , cardiology , mitral valve , electrocardiography , tachycardia
Objectives Proximity of atrioventricular (AV) conduction system to tricuspid, mitral and aortic valves renders it susceptible to injury leading to disturbances in patients undergoing valve operations and radiofrequency catheter ablations. Hence, the knowledge of topography of AV conduction system and its relations with surrounding cardiac structures is indispensible. Methods In 20 cases, a tissue block of 3×4 cm at AV septal junction was excised which included the borders of Koch's triangle. The block was divided into three equal segments by parallel vertical incisions made perpendicular to insertion of septal leaflet of tricuspid valve. Each segment was processed for Hematoxylin & Eosin and Gomori stain. Results The upper pole of compact AV node was at the level of mitral valve leaflet in 50% cases. Lower pole of AV node was vertically above tricuspid septal leaflet and at the level of muscular IV septum in 100% and 66.7% cases respectively. The subendocardial depth of upper and lower pole of AV node was 1.45±0.6 mm and 0.92±0.3 mm respectively. Minimum subendocardial depth (0.68±0.2mm) was seen at the center of compact AV node. Penetrating bundle of His was seen at the level of tricuspid septal leaflet just deep to it, while Branching bundle of His was 1.98±1.5 mm below the tricuspid septal leaflet. AV nodal extensions began at the level of mitral valve leaflet while its inferior extension ended 2.92±1.3 mm above tricuspid septal leaflet. Conclusion Prior knowledge of distances of AV conduction system from the surrounding landmarks might help in surgical incision planning, safe suture placement and successful device insertion. Support or Funding Information From Director PGIMER, Chandigarh, India.