###Human: What are the emergency symptoms of SVT? ###Assistant: Hello. The episode that you described is probably an SVT episode. The warning signs are the same which you had such as sudden palpitations, dizziness, shortness of breath and chest pain, and lastly, it can lead to syncope. However, these are not directly life-threatening. This can be an SVT like PSV (paroxysmal supraventricular tachycardia) 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. Usually, ECG is normal as it is generally done in between the events. ECG done during episodes will show abnormality. You will need 24-hour Holter monitoring which will correlate your symptoms with heart rate and rhythm. To abort such incidents, you should try to cough hard. Till the time your evaluation is complete, you can ask your local doctor for tablet Metoprolol or Ciplar LA 20 mg (Propranolol) once a day. Another option is of electrophysiological study which is an 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 doubts.