Not able to pass param to ng-inlude using ng-init

I am adding a template to my page using ng-include, but I want the header to have text that I want to pass from the parent controller. Data within the template is available through a separate listener. Heading is a value specified outside of it.

<div ng-include="'throughput.html'" ng-init="heading = 'CPU Throughput'">

This is my template controller

export class ThroughputController {
    heading: any;

    constructor(private $q: angular.IQService, private $scope: angular.IScope) {
        let vm = this;

When my template's controller is initiated I'm not getting the value of heading in there. It is undefined. I am able to write this same code in javascript and it all works. But my application is using TS and I'm new to TS and I don't know what I am missing. Any help is greatly appreciated. We using AngularJS 1.6.