Use the arduino print line function, like you are printing debugging data to the Arduino development GUI.
Set up the arduino interface to write your serial output to a known serial port, and test it.
Set up your labview VISA interface to read from that same port.
Connect Arduino and look in control panel, and check that you can see the arduino as a device, connected to the correct port.
Run your Arduino program and labview at the same time. (That is to say, after you have uploaded the program to arduino, and tested it with Arduino development GUI, shut down the development GUI and just plug your Arduino into the USB port, and power up the Arduino. Your program will start running. You could put a couple of LEDs on the arduino board to indicate program status, like "Green LED on means all OK.")
Arduino will pump data to the serial port as your program executes. Labview reads from the port.
(You can't see this until your labview program captures the data and then displays it for you, assuming you put something in your VI to show "bytes received" or whatever)
You'll have to manage setting up your VI to check for "bytes available at port" flushing the buffer etc.
Arduino will simply keep sending data to the port, as your program demands.
