ECG of the Week - 17th December 2012 - Interpretation

This ECG is from 46 yr old man presenting with several months of exertional dysponea and fatigue. At the time of review his BP was 110/60 mmHg.
Thoughts ? Differential diagnosis ?

Click to enlarge

Rate:

• Atrial Rate 83 bpm
• Ventricular rate 42 bpm

Rhythm:

• Regular
• No relationship between P waves : QRS complexes

Axis:

• Normal (~65 deg)

Intervals:

• PR - No relationship
• QRS - Normal (80ms)
• QT - 440ms (QTc Bazette ~ 390 ms)

Segments:

• Apparent ST elevation in V3 although likely to be secondary to p wave superimposition

Interpretation:

• Complete heart block with junctional escape rhythm.

Differential Diagnosis

• Ischaemia
• Medications
• Cardiotoxic agents
• Therapeutic
• Delibrate Self Harm
• Electrolye / Acid-base disturbance
• Aortic Valve Disease
• Congenital Cardiac Disease - Valvular or EP disturbance
• Sarcoidosis
• Myocarditis
• Thyroid Dysfunction - Hyper- or hypo-
• Case reports here, here, here, and here.

What happened to this patient ?

• Stress Echo - Nil evidence ischaemia with normal LVEF
• Cardiac MRI - Nil evidence sarcoidosis
• PET Scan - Nil evidence sarcoidosis
• Nil reversible / correctable cause found for CHB
• Dual chamber PPM Implanted (MRI Compatible)

Thanks to both Christopher and Vince DiGuilio for their comments on this ECG.

Don't forget to check out Christopher's works over at http://sixlettervariable.blogspot.com.au/ and if his Blogger profile is right, over here as well Paramedicine101. 

Check out Vince's Google+ ECG+ Community for more excellent ECG discussions, and check out his website The Medical Appraoch to EM. You can also follow Vince on twitter @MedicalApproach

Thanks to Dr Shakeeb Razak for sharing this interesting case.

References / Further Reading
 

Life in the Fast Lane

• Complete heart block here

Articles

• Kandolin R, Lehtonen J, Kupari M. Cardiac sarcoidosis and giant cell myocarditis as causes of atrioventricular block in young and middle-aged adults. Circ Arrhythm Electrophysiol. 2011 Jun;4(3):303-9. PMID: 21427276 Full text here

Textbook

• Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.