Hello! Welcome and thank you for asking on HCM! Regarding your concern, I would explain that your symptoms seem to be related to anxiety and psychological withdrawal syndrome. It is known that anxiety is associated with ectopic heart beats and arrhythmia. But, a cardiac disorder can not be excluded by this symptomatology. I would like to know your age and if you have any family history for any cardiac disease. I recommend consulting with your GP for a careful physical examination, a resting ECG, a chest x ray and some lab tests like : complete blood count, fasting glucose, kidney and liver function tests, blood electrolytes, thyroid hormone levels). If suspicions for a cardiac arrhythmia or lung disorder are raised, you need to perform an ambulatory 24 hour ECG monitoring and respiratory function tests. If all the above tests result normal, the most probable diagnosis would be anxiety related to smoking withdrawal syndrome. In such a case, I would recommend consulting with a psychiatrist to consider the possibility of starting anxiolytic drugs or an antidepressant to prevent these episodes. Hope to have been of help! Greetings! Dr. Iliri