<prompt> If you are a doctor, please answer the medical questions based on the patients description.My left side of my chest just started pulsating for just about 10-20 sec stopped for a few seconds then started again then stopped. I have a 3cm hole between the left and right ventrical of my heart so one chamber where the blood flows pushes into the other. I ve had it checked out within the last year and everything is good. My heart hasn t gotten bigger and the doctor said since I haven t had any problems its not wise to sew it up. Just wondering if this has anything to do with the pulsating? I have no pain, just curious because you can see my chest pulsate when im lying down.  <response>: What you described is a ventricular septal defect as you say, all if fine during last consultation. Now here I would like to say much transient arrhythmia heart rhythm problem s are known to occur with VSD, doing an ECG at the time of such episode and if on daily basis its happening a 24 hour holder, if still rarer a loop recorder for a week, will help us know what is the type of such disturbance and if anything found can be treated with a small dose of medication. Regards 