inter nodal pathway | Dr.S.Venkatesan MD

Posts Tagged ‘inter nodal pathway’

Unfolding the secrets of Inter nodal pathways !

Posted in Atrial fibrillation, cardiac physiology, tagged atrial conduction physiology, electrophysiology of atrial conduction, inter nodal conduction, inter nodal pathway, sa node to av node connection, thorel bachman wenkeback pathways on December 24, 2013| Leave a Comment »

Image source and courtesy http://www.heart-consult.com

Answer

I am afraid the 4th response is closer to truth .Readers may share their thoughts. If there are three distinct pathways spreading widely connecting the two spacious chambers and converging again with precision at the compact AV node , it is a marvel .

Further , If these pathways are real , we must experience different types of inter nodal re-entrant tachycardias.Of-course ,we do come across few macro re-entrant tachycardia in the form of atypical atrial flutters They need a close watch .Tracking these arrhythmia may throw light on existence of these pathways.

However, the presence of nodal approaches with preferential inputs to AV node from different parts of atria would indeed suggest existence of such pathways !

Further study

What does sophisticated carto and other electro anatomic mapping say about these inter nodal pathways ?

Reference

An excellent article from imperial college London

Atrial anatomy and inter nodal pathway thorel bachman wenkeback

Heterogeneous three-dimensional anatomical and electrophysiological model of human atria . Seemann G, Höper C, Sachse FB, et al. Institute of Biomedical Engineering, University Karlsruhe (TH), Kaiserstrasse 12, 76128 Karlsruhe, Germany. Transact A Math Phys Eng Sci 2006 Jun 15; 364(1843) :1465-81.

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ECG suggests LAE . . . Echo reveals an absolutely normal Left atrium . . . what is your comment ?

Posted in Cardiology - Electrophysiology -Pacemaker, cardiology -ECG, Infrequently asked questions in cardiology (iFAQs), tagged inter atrial block, inter nodal pathway, lae in ecg, lae vs inter atrial block, left atrial enlargement in ecg on February 8, 2013| Leave a Comment »

This is an ECG of a 42 year old man .He was reported as Left atrial enlargement (LAE) and was referred for echocardiography . His echo was normal . LA measured 2.5 X 3.1 cm .The consultant called back the echo lab , to verify the left atrial dimension .He thought he was very sure of LAE .It took considerable time to convince him about the credibility of the echocardiographer . He was right after all . . . still . . . ECG was also looked convincing for LAE !

Is this phenomenon of wide P wave with normal atrial dimension common ?

Yes it is . It underscores poor sensitivity of ECG in the diagnosis of LAE .The P wave abnormality in the above patient is due to Inter atrial block (IAB ) . This widens the p wave .

What are the types of Inter atrial block ?

P wave widening is not synonymous with LAE .(Here P waves widened due to sluggish inter nodal pathway and inter atrial pathway .It is something like QRS widening in bundle branch blocks )

Final message

IAB is an important differential diagnosis for LAE . The significance of which is not entirely clear . It is possible IAB precede LA enlargement .It can even trigger AF due to inhomogeneity.

Even though IAB was reported in 1950s (Puech P* ) , it was rarely considered important With increasing incidence of atrial arrhythmia in aging population , IAB is expected to come into the lime- light again . The sophisticated electro anatomical mapping can unravel the mysteries surrounding this entity .

Reference