From the Research
Early ECG changes in non-bilious vomiting due to gastric outlet obstruction primarily reflect electrolyte disturbances, especially hypokalemia and metabolic alkalosis, which can lead to T wave sagging, among other changes. The most common ECG changes associated with hypokalemia include flattened or inverted T waves, the appearance of U waves, ST segment depression, and prolonged QT intervals 1. These abnormalities occur because persistent vomiting leads to significant loss of gastric acid and potassium, creating a hypochloremic, hypokalemic metabolic alkalosis. Key points to consider in the ECG changes due to gastric outlet obstruction include:
- Potassium depletion particularly affects cardiac conduction, altering repolarization patterns visible on ECG.
- In severe cases, hypokalemia (K+ < 3.0 mEq/L) may cause prominent U waves that merge with T waves, creating a "camel hump" appearance.
- Additionally, patients may develop sinus bradycardia or tachycardia depending on their volume status and autonomic response.
- These ECG changes are generally reversible with correction of fluid and electrolyte imbalances, which should be addressed promptly alongside treatment of the underlying gastric outlet obstruction 2, 3. Given the options provided, T wave sagging (D) is a possible early ECG change, although the most specific changes are typically related to hypokalemia, as described. It's crucial to address the underlying cause of gastric outlet obstruction and correct electrolyte imbalances to prevent further complications and improve patient outcomes.