This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
In acute pulmonary embolism, the most frequent ECG finding is 
Select and explain. 
A. S1Q3T3 pattern, B. P. pulmonale, C. Sinus tachycardia, D. Right axis detion
C: Sinus tachycardia
Answer: C: Sinus tachycardia 
Explanation: The most frequently cited abnormality in pulmonary embolism is sinus tachycardia.Apa from that,it also shows S1Q3T3 sign-an S wave in lead I,a Q wave in lead III,and an inveed T wave in lead III.This finding is relatively specific. S1Q3T3 pattern in ECG of pulmonary embolism is also termed as Mc Ginn White Sign. Reference:Harrison's medicine-18th edition,page no:2172.