Sgarbossa and pacemakers

18 Dec

quick refresher’s HERE and HERE

WHAT’S THE BIG IDEA WITH PACEMAKERS?

–ventricularly paced ECGs are tough to interpret for MI, because the signal starts somewhere other than the SA node/AV node/Purkinje fiber expressway, giving it a wide QRS complex pattern similar to a bundle-branch block

WHAT IF YOU USE SOMETHING THAT WORKS IN LBBB FOR PACED ECGs?

Study by Maloy et al:

57 study patients, retrospective review

  • ventricularly paced ECG
  • elevated cardiac markers <12hrs after ED ECG
  • diagnosis of AMI

99 control patients

  • ventricular-paced ECG
  • negative cardiac markers

A blinded board certified cardiologist reviewed all ECGs for Sgarbossa criteria.

RESULTS:

“ST-segment elevation of 1 mm concordant with the QRS complex”

  • no ECG fit this criterion;

“ST-segment depression of 1 mm in lead V1, V2, or V3,”

  • sensitivity was 19% (95% CI 11-31%),
  • specificity 81% (95% CI 72-87%),
  • likelihood ratio of 1.06 (0.63-1.64);

For “ST-segment elevation >5mm discordant with the QRS complex,”

  • sensitivity was 10% (95% CI 5-21%),
  • specificity 99% (95% CI 93-99%), 
  • likelihood ratio of 5.2 (1.3 – 21).

 

BOTTOM LINE:

 “the most clinically useful Sgarbossa criterion in identifying AMI was ST-segment elevation >5mm discordant with the QRS complex. This characteristic may prove helpful in identifying patients who may ultimately benefit from early aggressive AMI treatment strategies.”

translation: if you see discordant ST elevation >5mm in a paced rhythm, worry about an MI.

interesting that the least useful rule in LBBB might be the most useful in paced rhythms.

 

 

References: article, nice review on pacers at lifeinthefastlane; picture

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One Response to “Sgarbossa and pacemakers”

Trackbacks/Pingbacks

  1. Sgarbossa revisited – MI in LBBB | DAILYEM - September 25, 2013

    […] WHAT IF ITS PACED? […]

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