ECG Change seen in Pulmonary embolism is:
**Core Concept:** Pulmonary embolism (PE) is a life-threatening condition caused by the blockage of a pulmonary artery by a blood clot. In electrocardiogram (ECG), PE can lead to changes in cardiac output, heart rate, and myocardial ischemia, which can manifest as specific ECG abnormalities.
**Why the Correct Answer is Right:** In a patient with pulmonary embolism, the ECG changes are generally due to the following mechanisms:
1. **Increased cardiac output (Option D):** As the heart works harder to pump blood through the blocked pulmonary artery, it leads to an increase in heart rate and cardiac output. This results in an elevated QRS duration, which is seen in the ECG as widened QRS complex.
2. **Myocardial ischemia (Option C):** Due to reduced blood flow to the heart muscle, ischemia occurs, causing changes in the ECG. The ECG shows ST-segment elevation and T-wave inversion, which are indicative of myocardial ischemia.
**Why Each Wrong Option is Incorrect:**
1. **Decreased cardiac output (Option B):** This is an incorrect answer because pulmonary embolism leads to increased heart rate and cardiac output, as mentioned above, not a decrease.
2. **Atrial fibrillation (Option A):** While atrial fibrillation is a potential complication of PE, the ECG changes described in the options are not specific to atrial fibrillation and are also seen in other conditions, making it less likely as an answer compared to the correct options.
**Clinical Pearl:**
A key clinical pearl to remember while interpreting ECGs is the "Rule of Six" – if you see six or more pathognomonic ECG changes (ST-segment elevation, T-wave inversion, or QRS prolongation), the diagnosis of PE should be considered. This helps in prompt recognition and management of a potentially life-threatening condition.
**Correct Answer:** D (widened QRS complex) and C (ST-segment elevation and T-wave inversion) are the correct answers as they represent the specific ECG changes seen in pulmonary embolism due to increased cardiac output and myocardial ischemia. The other options (A and B) are incorrect and represent different ECG changes seen in other conditions, making them less likely in a patient with pulmonary embolism.