Hello, I don t think that the pneumothorax is responsible for the palpitations since they are still present now that the lung is fully expanded. The primary lung problem (that you took the biopsy for) may have to do also, or a possible cardiac origin. I suggest you do a cardiac sonography and a 24h ECG Holter monitoring to get more information for the palpitations and to choose the right treatment if it is needed. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Anila Skenderi, General & Family Physician