Dr.S.Venkatesan MD

The other day my fellow got a call  from surgical ward for emergency ECG opinion for a  suspected Inferior MI .It later turned out to be an acute cholecystitis.

One of the important  anatomical mis-perception  among physicians ,  is to consider  inferior, posterior  and diaphragmatic surface  of heart  as separate entities .They are all  closely linked.In fact, they  more often  mean  the same  anatomical zones !

Heart is a dynamic suspended organ within the middle mediastinum .It  can assume a vertical or horizontal position due to number of surrounding anatomical  and physiological factors. (Diaphragm, Lung , being  important ).The ratio of intra thoracic vs Intra abdominal  volume  &  pressure determine whether the posterior surface of the heart is going to face the back of chest  or simply sit and  rest on the diaphragm .We know a horizontal heart is likely to inscribe q waves  in inferior leads .

Courtesy : Basic image source from digitallab3d

The  diaphragm can be termed as an  anatomical causeway , that isolates   thorax  from the  abdominal  cavity .Close encounters between the organs separated by this delicate biological  membrane is  always possible .This is especially true for electrical signals  which show little  respect for anatomical barriers .

This is the reason there are too  many abdominal conditions that mimic  inferior MI during a painful  emergency (and vice versa  when inferior  MI mimics  acute abdomen .) In  our  department , we   have witnessed  the following conditions mimicking Infero-posterior ACS.

1. Acute ascites with polyserositis
2. Gross obesity with APD
3. Posterior fat pad ( Necrosis ?)
4. Thickened pericardium
5. Minimal posterior pericardial effusion
6. Diaphragmatic pleurits
7. Esophageal spasm
8. Fundal air  trapping and ballooning after a heavy meal !
9. Acute duodenal ulcer perforation ( With gas under diapharam causing q waves)
10. Acute cholecystits
11. Diphragmatic hernia
12. Achalasia cardia
13. Pancreatitis

Final message

Do not rush to make a diagnosis of inferior wall MI when  you encounter inferior q waves  with  or without ST /T changes , especially  when the symptoms are atypical .