Hello, This can be a cardiac arrhythmia like psvt or atrial fibrillation, in which heart rate suddenly goes up and also suddenly decreases which gives feeling of palpitations. Usually ecg is normal as it is usually done in between the episodes. ECG done during episodes will show abnormality. You will need 24 hour holter monitoring. So visit nearby cardiologist for these investigation. ln order to abort such episodes you should try to cough hard. Is there any stress or anxiety associated. Till the time your evaluation is complete, you can ask your local doctor for tab ciplar LA 20 mg once a day which will control the palpitations. If none of the above is successful then last option is of electrophysiological studies which is invasive test which can diagnose and treat the arrhythmia permanently in most of the cases. Hope this helps you and get back if you have any other doubts.