The correct interpretation is atrial flutter with 2:1 conduction. In the absence of exercise, a tachycardia in a range of 130-150 beats/min with a regular rate should raise suspicion for atrial flutter. The presence of 2:1 conduction implies an atrial rate of 310 beats/min, within the range of an atrial macro-reentrant tachycardia.
There are two P waves for each QRS complex. One is hidden in the T wave in lead II, and the other occurs immediately before the QRS complex in leads II and aVF. Note that the P wave immediately preceding the QRS complex is not representative of a short PR interval with preexcitation, as seen in Wolff-Parkinson-White syndrome.
In this otherwise healthy male with no history of arrhythmia, the most likely cause of atrial flutter is alcohol consumption.
The patient was cardioverted to normal sinus rhythm and has had no further episodes.