Unusual ECG, ventricular extra systole following shortly after each sinus beat?

Hi
Stumpled upon this ECG yeasterday, has anyone seen something like it?

33 year old woman, no known diseases, now presenting with an extrauterine pregnancy (not sure for how long she had been pregnant, but she was in no way acute ill), no palpitations, no chest paid, no seizure or fainting. she tells that she had an ECG taken some years ago, with no abnormalitys. 
St.c 1. and 2. heart sound with no abnormality =pp, followed by some murmur-like sound, not = any clear perifer puls.
Took several ecg's over a period of 15min, all the same pattern

To me it looks like each sinus beat is followed shortly after by a ventricular extra systole.
I can see no psysiological explanation for this?
Is this a common?

Source: Doc2Doc BMJ Cardiology - July 10, 2014 Category: Cardiology Authors: Munthen Source Type: forums