It is not the way you are thinking.
miller had calculated through some verses of Bible that the Return of Christ would happen in 1844.
Let me demonstrate something to you, so, you may know where this idea came from. (This is not to convince you, but to give you some info that you seem not to be aware of)
There is a prophecy in OT Bible about first coming of Messiah of Jews. It says Messiah shall be cut off in Seventy Weeks.
Now, counting from year 457 BC which is when the third command was issued for building the Temple, seventy weeks, it comes to year 33 AD. Here it is believed seventy weeks is 490 days, and each day is counted as a year as per some verse of Bible. Thus 490 years after 457 BC is a year that the Messiah is cut off. This is believed to match with the year that Jesus was put to death.
Now, there is another Prophecy in OT which is about the time of End or Return of Christ in 2300 days. If you count again from the same origin, year 457 BC, 2300 years, it comes to 1844 AD. This is how miller learned year 1844.
Now, in Persia, some Shia expected in the same year Manifestation of the Qaim, the Mahdi. Their expectation was calculated based on Prophecies in Islamic Traditions, and it was because in their traditions it was alluded that Mahdi comes 1000 years after Guidance of Islam. Thus since in Shia the last imam had passed away in year 260 AH, they believed in year 1260 AH, Mahdi comes. Now 1260 AH happens to be 1844 AD. So, no my friend. People of Persia did not pick up from Miller.