A 65- yr old man presented to the emergency room with a one day history of rapid heart pounding and fatigue.He has had no complaints of chest pain, dyspnea, or syncope.He had an uncoplicated myocardial infarction 8 yrs ago and has had no angina since that time.He has history of borderline high blood presure and elevated cholestrol; he had smoked 1 pack of cigarette per day but stopped smoking after his heart attack.No thyriod symptoms has been reported.

examination:

revealed awell-devoloped man not in acute distress,not cyanosed pale or jundiced.His blood pressure was 140/90.A rapid irregular pulse of 160 was noted with a pulsus deficit of 20 beats.The respiratory rate was 10 per min.The JVP was normal.Cardiac palpation and auscultation showed that ther was no cardiac enlargment.Heart sounds are normal,no murmers.Chest was clear.Other examinations were entirly normal.

1-what is the diffrential diagnosis of irregular irregular pulse?

2-What is the most likely dignosis.?why.?how you will confurm that.?

3-what are the causes of this abnormal rhythm??

4-what extra cardiac sound that never present with this abnormal rhythm?.

5-what line of investigation you may do for such a patient?

6-what is the line of manegment in this pateint

7-?do you think D/C shock is an optin for this patient??