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 .
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.
- Acute ascites with polyserositis
- Gross obesity with APD
- Posterior fat pad ( Necrosis ?)
- Thickened pericardium
- Minimal posterior pericardial effusion
- Diaphragmatic pleurits
- Esophageal spasm
- Fundal air trapping and ballooning after a heavy meal !
- Acute duodenal ulcer perforation ( With gas under diapharam causing q waves)
- Acute cholecystits
- Diphragmatic hernia
- Achalasia cardia
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 .