Hello, This can be a anxiety, anemia or, cardiac arrhythmia like psvt or atrial fibrillation, in which heart rate suddenly goes up and also suddenly decreases. Blood pressure falls during these episodes and one has dizziness, fainting, blackouts, sometimes syncope. Ecg should be done and is normal as it is usually done in between the episodes. ECG done during episodes will show abnormality. You will need also 24 hour holter monitoring if ecg is not informative. So visit nearby cardiologist for these investigation. Also, hemoglobin and thyroid test should be done. ln order to abort such episodes you should try to cough hard. Is there any stress or anxiety associated, as it can also cause this. Till the time your evaluation is complete, you can ask your local doctor for tab ciplar LA 20 mg once a day. Do you have any upper abdominal pain, nausea, bloating, burping etc. if yes it could indicate gastritis and acidity.