EKG of the Week – Week 7 ANSWERS

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Hey Guys,
     Solution to this week’s EKG of the week!  Really good info from life in the fast lane on EKG changes in patients with COPD and pulmonary disease (https://litfl.com/ecg-in-chronic-obstructive-pulmonary-disease/)
First of all, why do we see changes on an EKG at all with a patient with pulmonary disease?  Think back to medical school where someone posted a chest X-ray on a slide that looked like this:

You probably remember thinking, where’s the heart?  Well funny story, the heart is feeling that way too.  The lungs look like nothing on an X-ray, because they’re filled with air, but they’re actually putting a ton of pressure on the heart.  All that pressure causes compression of the heart. Also, the heart is attached to a few important structures, like the aorta and the pulmonary arteries which are fixed in the chest.  All that pressure from the lungs causes the heart to become rotated and the RV gets displaced anteriorly and the LV gets displaced posteriorly.  There is also a lot of air between the heart and the EKG lead, due to hypertrophy of the lungs, so you will see a low voltage QRS.  


Lot of text.  Take aways:

  • Low amp QRS due to increased distance between EKG lead and heart
  • R Axis due to compression and twisting of the heart 2/2 large lungs and immobile heart


Let’s talk about Cor Pulmonale for a second.  No, this isn’t a medicine lecture, but just understanding the basics can help us understand why we get super big P waves in patients with chronic lung disease.  

First of all, what is Cor Pulmonale?  “Cor pulmonale is defined as an alteration in the structure and function of the right ventricle (RV) of the heart caused by a primary disorder of the respiratory system. Pulmonary hypertension is often the common link between lung dysfunction and the heart in cor pulmonale” (https://emedicine.medscape.com/article/154062-overview). Think of it as RV hypertrophy 2/2 a lung problem.


Ok, so how do we get there?  Remember that patients with pulmonary disease have chronic hypoxia.  What does the lung do when it has hypoxia?  It shunts blood away from that area (hypoxic vasoconstriction).  The problem is that in these patients there isn’t a lot of good lung left, so the heart has to pump a lot of blood through a little bit of good lung, leading to, you guessed it, RV hypertrophy.

Again, lot of text.  Take aways: 

  • Hypoxia in the lung -> vasoCONSTRICTION
  • The heart has to work hard to pump a lot of blood to a little bit of good lung -> RV Hypertrophy


So to sum it up, what do we see on patient’s EKGs with Pulmonary disease?Prominent P waves in the inferior leadsFlattened or even inverted P waves in AvL and lead IDecreased QRS Amplitude (2/2 increased “stuff” between the heart and EKG leads)Slow R Wave progression (heart is rotated) Exaggerated atrial depolarization causing a “Sagging” of the PR and ST segments below the TP baseline:

Eventually patients can develop:

  • RBBB
  • MAT
  • But these are topics for another day.

So what were we seeing in our patient’s EKG?

  • Large P waves in the inferior leads
  • Flat P waves in AVL
  • Slow R Wave progression
  • R Axis deviation

So in conclusion, don’t smoke and have healthy lungs!

Published by sammcemed@gmail.com