Hi. I would advice you to kindly consult a cardiologist
so that maybe she can be put on a holter monitor
. This is a device that records the graphical representations of the heart beats for 24 hours. Only once we have the actual representations can we decide what might be the cause. An ECG gives us an idea of the heart activity for that specific period while a holter can give us an idea of the whole 24hrs. She might be suffering from ectopic beats. Hope her blood pressure is under control.