What ECG change is expected when the pericardial needle contacts the heart during pericardiocentesis?

What ECG change is expected when the pericardial needle contacts the heart during pericardiocentesis?

• A. ST elevation
• B. ST depression
• C. No change
• D. T wave inversion

Answer: (A)

When the needle actually touches the heart during pericardiocentesis, the myocardium sustains acute injury. This injury current creates a transmembrane potential difference between the injured region and healthy tissue, leading to a rise of the ST segment on the ECG — an immediate, direct sign of myocardial injury. If the needle is redirected and the pericardial space is entered safely, the injury ceases and the ST elevations may resolve. ST depression would point to subendocardial ischemia, T wave inversions are not the immediate reflection of a needle-induced myocardial puncture, and no change would imply no injury.

When the needle actually touches the heart during pericardiocentesis, the myocardium sustains acute injury. This injury current creates a transmembrane potential difference between the injured region and healthy tissue, leading to a rise of the ST segment on the ECG — an immediate, direct sign of myocardial injury. If the needle is redirected and the pericardial space is entered safely, the injury ceases and the ST elevations may resolve. ST depression would point to subendocardial ischemia, T wave inversions are not the immediate reflection of a needle-induced myocardial puncture, and no change would imply no injury.