June 13, 2011

A case of bradycardia - biliary disease or acute coronary syndrome?

A middle-aged man comes to the ED with one day history of severe pain in the upper abdomen. He is feeling increasingly uncomfortable and has nausea without vomiting. He appreciates his pain as VAS 7-8. On physical examination he is tender on palpation in the epigastrium, physical examination is otherwise completely normal. You get an ECG with no signs of ischemia but you observe sinus bradycardia at 37 beats per minute.

The lab results unfortunately return a hemolyzed Troponin-T but the LFT (liver functional tests) show ALP=3.2, GGT=8.8, ALT=1.4 and AST=2.3 (slightly elevated, suggesting cholestasis). Could the pain have a cardiac etiology?

Flu in Oakland 1918 Inferior MI and diseases of the upper gastrointestinal tract (gallbladder, stomach/esophagus especially) can present in very similar ways. Besides epigastric pain, patients commonly describe bloating and reflux-like symptoms due to vagal stimulation and gastric distension. Vagus stimulation explains why up to 40% of patients with inferior MI have sinus bradycardia (Bezold-Jarisch reflex). 1st to 3rd degree AV block is also common but how the mechanism of the AV node inhibition is not known.AST was for many years ago the only known cardiac marker. In the 1954 protocols for MI an elevated AST defined an acute coronary syndrome. Which in those days required hospitalization for bed rest mainly! It is a sensitive marker but highly nonspecific. LITFL (as usual) has an excellent article about the use LFTs, especially for the 'cut the crap' based approach of the emergeny physician
http://lifeinthefastlane.com/education/investigations-tests/liver-function-tests

All pain and physical stress, especially from stomach and intestines can potentially stimulate the vagus nerve and thereby cause bradycardia. The classical scenario is the elderly patient with gastroenteritis that comes to the ED after a syncope. The relationship between bradycardia and acute cholecystitis has actually been described previously and even given a special name, Cope's sign:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1795584/

Bradycardia in the case described above turned out to be caused by an underlying acute cholecystitis, the patient had an infusion and was admitted for emergency surgery. A new Troponin T was taken and turned out to be normal. A new ECG revealed normal sinus rythm.