Hi doctor! Doctor let me ask if the heart disorder is dangerous?

Lately, I've been feeling tired and anxious. The heart rate is fast, sometimes slow, irregular, sometimes interrupted, lost rhythm. This symptom often occurs 30 minutes after eating or during intense activity. I feel very worried. When I went to the doctor, the doctor said that I had a neurological disorder, but I was hospitalized and took some medicine to return home. I do not see any specific treatment regimen for definitive treatment. So the doctor asked me to ask if my heart disorder is not completely treated with drugs, what should I do?

I'm 20 years old this year, I often have a fast heartbeat and a feeling of anxiety, I'm more tired than before, but when I go to the doctor and echocardiogram, I don't get sick, the doctor said my heart I'm healthy. I have researched on the web that my condition is a neurological disorder, can I ask if it is correct, doctor and how to treat cardiac neurological disorders for 20-year-olds? Thank you doctor.