Site hosted by Angelfire.com: Build your free website today!

Case #29

Your next patient is waiting in the ER. It is a 64 year old male with Chief complaint of Shortness of Breath. He has past medical history of Pulmonary Silicosis, DM and Diverticulosis. He has baseline dyspnea on exertion but recently has become more short of breath. He admits to fever, cough and sputum production for 3 days. On physical exam he has diffuse dry crackles in all lung fields and and the PMI in found at the Lower Left Sternal Border. The CXR shows a diffuse interstitial pattern and a RML consolidation. The labs are significant for an elevated WBC and no other significant findings. You start antibiotics. To complete the History and Physical you get an EKG. What is your interpretation of this EKG and how do you explain it?

Click here for better Image of EKG

 

With the history in mind this EKG is an example of a patient with likely long standing Pulmonary Hypertension due to his Interstitial Lung disease leading to Right Ventricular Hypertrophy and Right Atrial Enlargement.

Going with the systematic approach you will find that this is Sinus Rhythm @ around 80. The p wave morphology is classic for Right Atrial enlargement which is a tall upright pwave in v1 (greater than 1.5 mm and Tall p waves in II, II and AVF > 2.5 mm) The best way to remember the atrial abnormalities is that in v1 it should be biphasic. The first half accounts for Right atrial depolarization and is positive, and the second half accounts for Left atrial depolarization which is usually negative. So if you see an all positive p wave in v1, it should tip you off to Right atrial abnormality and if it is all negative that it should tip you off to left atrial abnormality. So in this case the p in v1 is all upright leading to the diagnosis.

The P-R interval is right on the cusp of being abnormal but it is not. (.19 sec).

The next diagnosis has to do with the QRS pattern. The axis is (+)150 degrees which is a right axis deviation. So how do we account for this. The first tip off is the precordial leads. The major vector in v1 is positive with a large R wave. Usually the major vector should be negative in v1. Also V2 actually looks like it is out of place because v3 resembles v1 and likely represents lead misplacement not reversal. So continuing on, the qrs width is also normal. So the R wave can not be explained with a conduction delay like RBBB which usually changes the vector to positive in v1. The next thing to think about is Right ventricular infarction but there is no clinical findings / lab findings and ST elevation./depressions that would suggest RV infarct. The next one to consider is RVH, which this actually is. Putting the precordial qrs characteristics along with the limb lead characteristics we can say that this pattern fits for RVH.

So to diagnose RVH we have a large R in v1, the R to S in ration in v1 is > 1(meaning the major vector is positive), the qrs duration is normal (meaning there is no RBBB to account for these findings), there is presence of Right atrial abnormality further supporting the diagnosis, there is right axis deviation > 100 degrees. The only other diagnosis that may be considered in this case is Left Posterior fascicular block (right axis / small q in II,III, AvF/ rS in I, AvL). But the key is that there are no precordial changes in LPFB so hence the only thing this can be is RVH.