An Unusual AV Dissociation
At first glance this has the appearance of a 2nd degree type I AV block. See if you can identify what is unusual about it.
In a 2nd degree type I AV block (Wenckebach) the PR interval gets progressively longer until there is a non conducted P wave or dropped QRS complex. In most cases the P-P interval is regular. Often the block occurs at the level of the AV node and has a narrow QRS complex. The rhythm is usually benign and requires no immediate treatment
In a 2nd degree type II block the conducted P waves have a consistent PR interval but there are some non-conducted P waves present. The non conducted P waves may have a 2:1, 3:1 ratio. The level of the block is around the bundle of HIS.
With complete heart block the atria and ventricles each have an independent rhythm. The P waves are not associated with the QRS complexes. If the level of the block is higher in the His-purkenje system then the QRS complex will have a narrow appearance with a junctional escape mechanism. A block below that level will have a wider complex with a ventricular escape mechanism
In this strip, the rhythm has a Wenckebach-like pattern with progressive lengthening of the PR interval. The P waves are inverted suggesting a junctional focus. The QRS is widened. The negative QRS complexes in V1 suggest that this might be an existing left bundle branch block. There is not a dropped complex in this rhythm. Also notice that on the 2nd, 6th, 11th and 16th complexes there apprears to be a P wave in the ST segement of the QRS complex.
Unusual findings
Any comments?
In a 2nd degree type I AV block (Wenckebach) the PR interval gets progressively longer until there is a non conducted P wave or dropped QRS complex. In most cases the P-P interval is regular. Often the block occurs at the level of the AV node and has a narrow QRS complex. The rhythm is usually benign and requires no immediate treatment
In a 2nd degree type II block the conducted P waves have a consistent PR interval but there are some non-conducted P waves present. The non conducted P waves may have a 2:1, 3:1 ratio. The level of the block is around the bundle of HIS.
With complete heart block the atria and ventricles each have an independent rhythm. The P waves are not associated with the QRS complexes. If the level of the block is higher in the His-purkenje system then the QRS complex will have a narrow appearance with a junctional escape mechanism. A block below that level will have a wider complex with a ventricular escape mechanism
In this strip, the rhythm has a Wenckebach-like pattern with progressive lengthening of the PR interval. The P waves are inverted suggesting a junctional focus. The QRS is widened. The negative QRS complexes in V1 suggest that this might be an existing left bundle branch block. There is not a dropped complex in this rhythm. Also notice that on the 2nd, 6th, 11th and 16th complexes there apprears to be a P wave in the ST segement of the QRS complex.
Unusual findings
Any comments?
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