To stream ANT+ sensor data live to Matlab should be possible in theory, but it s complicated.
An alternative could be the Garmin HRM Dual and live stream of BLE heart rate.
Garmin HRM Dual™ has ANT+®-Standard (2,4 GHz) und BLUETOOTH® 5.0 (BLE) support. There is an example in MATLAB wich should work with BLUETOOTH® 5.0 (BLE). You need probably the latest release of MATLAB (R2020a). I don t post here any links anymore to the MATLAB example “Modeling of BLE Devices with Heart Rate Profile which shows the modeling of Bluetooth® Low Energy devices with Heart Rate Profile using the Communications Toolbox™ Library for the Bluetooth® Protocol”, to avoid being warned for spreading SPAM. Garmin HRM Dual™ owners wanted who test whether the device is working with the MATLAB example code.