WordPress at a glance
filter is not described

heartbeat_send filter-hook . WP 3.6.0

Filters the Heartbeat response sent.

Usage

add_filter( 'heartbeat_send', 'filter_function_name_2742', 10, 2 );
function filter_function_name_2742( $response, $screen_id ){
	// filter...

	return $response;
}
$response(array)
The Heartbeat response.
$screen_id(string)
The screen ID.

Changelog

Since 3.6.0 Introduced.

Where the hook is called

wp_ajax_heartbeat()
heartbeat_send
wp-admin/includes/ajax-actions.php 3410
$response = apply_filters( 'heartbeat_send', $response, $screen_id );

Where in WP core the hook is used WordPress

wp-admin/includes/ajax-actions.php 425
add_filter( 'heartbeat_send', 'wp_auth_check' );