Lead Misplacement or Dextrocardia

 What is the dx?

Difficulty level:⭐️⭐️

Digitize using #PMCardio

What is your ECG rhythm interpretation?

A.Dextrocardia

B Ectopic atrial rhythm

C.SR, old lateral wall MI

D Wrong lead placement

Situs Soltius with Dextrocardia

I thought this was just an ordinary or classic strip but looking at it I found some twist...

Starting with the easy ones -

THE QRS

In the precordial leads - the R waves are taller in V1 and becoming smaller as we go from V2 to V6 (reversal of R wave progression). So looks like the leads are reversed but not. Also it seems that heart is going away from the leads. This is dextrocardia.

There are also Q waves noted in V4-V6. This is due to the septal depolarization with a LEFT TO RIGHT direction.

In cardiac malposition, the ECG can be used to localized the ventricle based on (red arrow) septal depolarization (producing Q waves in the precordial leads) In this case, the LV is on the left side/ (confusing? LV on the left in dextrocardia).

The Q wave in I may be due to RVH.

THE P WAVES

The P waves seems to be coming from the normal direction (axis about 45) or upright in I and aVF. RA is on the right side (RA to the right of LA or situs solitus of the atria)

Thus this fits the pattern of:

Situs soltius with dextrocardia
RVH (Q waves in I)

(sorry cannot show here cxr of this case)

The characteristic features are:

Upright P waves in I, normal P wave pattern in aVR and aVL
Major precordial QRS voltage lies in the right hemithorax.

**** You do not see the classsic inversions because this is not dextrocardia with situs inversus or mirror-image dextrocardia.

Good read - http://circ.ahajournals.org/content/116/23/2726.full.pdf+html

Here is also a nice slide set presentation for cardiac malposition - http://www.slideshare.net/smcmedicinedept/ecg-cardiac-malpositions

Ectopic Atrial Rhythm in Dextrocardia

No clinical hx. What is your interpretation?

Image Case (Digitized using PMCardio App)

This is a regular narrow QRS complex rhythm with inverted P waves in I, inferior leads, V2-V6 and upright in aVR with PRI of around 0.16 seconds. There is low QRS voltage in V4-V6. The leads are in the correct location. This is dextrocardia (Image 2) with ectopic atrial rhythm. P waves that are in the superior direction (ectopic atrial pacemaker) can be seen in patients with polysplenia syndrome (noted on this patient).

Image 2 - Chest x-ray

Reference:

Park M. 2016. Park's Pediatric Cardiology Handbook. 5th ed. PA Elsevier

Surawicz B and Knilans TK. 2008. Chou’s Electrocardiography in Clinical Practice. 6th ed. PA. Saunders-Elseiver

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