Progressive Care Nursing Certification (PCCN) Practice Exam

What is the most common ECG change observed in patients with pulmonary embolism?

1. Q waves in AVR and Lead I

2. tachycardia

3. bradycardia and ST segment depression

4. high degree AV blocks

The correct answer is: tachycardia

Tachycardia is indeed the most common ECG change observed in patients with pulmonary embolism. This occurs as a physiological response to the decreased oxygenation and potential strain placed on the right side of the heart when a blood clot blocks a pulmonary artery. The body compensates for this decrease in oxygen delivery and impaired pulmonary blood flow by increasing heart rate to maintain cardiac output and improve perfusion to vital organs. In the setting of pulmonary embolism, the heart attempts to accelerate its rate to counteract the effects of the blockage. Consequently, sinus tachycardia can be a key indicator of this condition and is often the earliest and most frequently observed change on an ECG. Other ECG changes associated with pulmonary embolism can occur, but tachycardia remains the hallmark finding. Understanding this helps in quickly recognizing a potential pulmonary embolism, allowing for timely intervention and treatment.