GA pilot reported turning to the incorrect heading due to misunderstanding ATC instructions.

Attributes
ACN	1560355
Time
Date	201807
Local Time Of Day	1201-1800
Place
Locale Reference	ATL.Airport
State Reference	GA
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	SR22
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct Vectors
Flight Plan	IFR
Person 1
Function	Captain Single Pilot Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 21 Flight Crew Total 1120 Flight Crew Type 787
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

I was traveling direct and under ATC. I was descending from 7000 feet to 4000 feet in IMC to avoid weather buildups. During the descent ATC contacted and I understood told me to turn west to 290 degrees. I started the turn and the controller continued to say turn but they were very excited; repeating the instruction. I kept reporting back that I was turning 290. I began and completed my turn to 290 as I was descending to 4000 feet. I thought that I understood their instructions correctly as I was just west of class 'B' airspace and it made sense to me to turn away from it. If there was any aircraft near it did not show up on my TCAS so it would have been a few miles away and not in direct conflict. I later found out the controller was saying turn left to 090. The 'to' caused me to understand 290. I did not hear the '0'. The controller was very busy and hard to understand; was very excited and talked very fast.

Original NASA ASRS Text

Title: GA pilot reported turning to the incorrect heading due to misunderstanding ATC instructions.

Narrative: I was traveling direct and under ATC. I was descending from 7000 feet to 4000 feet in IMC to avoid weather buildups. During the descent ATC contacted and I understood told me to turn west to 290 degrees. I started the turn and the controller continued to say turn but they were very excited; repeating the instruction. I kept reporting back that I was turning 290. I began and completed my turn to 290 as I was descending to 4000 feet. I thought that I understood their instructions correctly as I was just west of Class 'B' airspace and it made sense to me to turn away from it. If there was any aircraft near it did not show up on my TCAS so it would have been a few miles away and not in direct conflict. I later found out the controller was saying turn left to 090. The 'to' caused me to understand 290. I did not hear the '0'. The controller was very busy and hard to understand; was very excited and talked very fast.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.