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Second degree AV block with 2 to 1 conduction

2/18/2017

Can you tell whether Morbitz type I or II?

It is not always possible to determine the type of conduction disturbance producing a fixed ratio block, although clues may be present.
Mobitz I conduction is more likely to produce narrow QRS complexes, as the block is located at the level of the AV node. This type of fixed ratio block tends to improve with atropine and has an overall more benign prognosis.
Mobitz II conduction typically produces broad QRS complexes, as it usually occurs in the context of pre-existing LBBB or bifascicular block. This type of fixed ratio block tends to worsen with atropine and is more likely to progress to 3rd degree heart block or asystole.
However, this distinction is not infallible. In approximately 25% of cases of Mobitz II, the block is located in the Bundle of His, producing a narrow QRS complex. Furthermore, Mobitz I may occur in the presence of a pre-existing bundle branch block or interventricular conduction delay, producing a broad QRS complex.
The only way to be certain is to observe the patient for a period of time (e.g. watch the cardiac monitor, print a long rhythm strip, take serial ECGs) and observe what happens to the PR intervals. Often, periods of 2:1 or 3:1 block will be interspersed with more characteristic Wenckebach sequences or runs of Mobitz II.

Reference:
http://lifeinthefastlane.com/ecg-library/basics/fixed-ratio-blocks/

After observation under ECG monitor for a prolonged period of time, we found that this patient is likely to have a high grade AV block.

Returning travelers with fever

2/16/2017

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Medscape CDC Expert Commentary

http://www.medscape.com/viewarticle/875380

Leptospirosis conjunctival suffusion

Leptospirosis petechial rash

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BRUE

2/16/2017

http://pediatrics.aappublications.org/

BRUE replaces the old term ALTE

BRUE = Brief Resolved Unexplained Event

Mount Fuji sign

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CT scan: Tension pneumocephalus secondary to frontal sinus fracture.

https://radiopaedia.org/

https://radiopaedia.org/articles/mount-fuji-sign-1

Glottic impersonation

Observing the endotracheal tube (ETT) pass through the vocal cords is widely taught and promoted as a means to ensure correct ETT placement. However, in isolation, this may be an insufficient way to determine success. The accompanying image highlights why seeing the ETT go through the vocal cords may not be as “gold” a standard for confirmation of correct ETT placement as it was once thought and has now been usurped by waveform capnography or bronchoscopy.

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Second degree AV block with 2 to 1 conduction

Can you tell whether Morbitz type I or II?

After observation under ECG monitor for a prolonged period of time, we found that this patient is likely to have a high grade AV block.

Returning travelers with fever

Medscape CDC Expert Commentary

Leptospirosis conjunctival suffusion

Leptospirosis petechial rash

WHO Fact Sheets

BRUE

BRUE replaces the old term ALTE

Mount Fuji sign

Glottic impersonation

Glottic impersonation

AuthorTwitter: @jackcfchong[email protected]

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Twitter: @jackcfchong
[email protected]