Create an AWS Step Functions workflow to monitor the CloudWatch alarm's state. Configure the Step Functions workflow to terminate with an error if the alarm is in the ALARM state. Introduce a new stage in the pipeline between each region's deployment stage, incorporating an action to trigger the Step Functions workflow.

Set up an AWS CodeDeploy application to deploy a CloudFormation template with automatic rollback. Integrate the CloudWatch alarm as the health check for the CodeDeploy application. Eliminate the CloudFormation actions from the pipeline. Add a CodeDeploy action to the pipeline stage for each region.

Establish a new pipeline stage for each region where the application is deployed. Configure a CloudWatch alarm action for this new stage to assess the CloudWatch alarm's state and terminate with an error if the alarm is in the ALARM state.

Configure the CloudWatch agent on the EC2 instances to send the application's status to the Route 53 health check. Introduce a new pipeline stage for each region where the application is deployed. Set up a CloudWatch alarm action to terminate with an error if the CloudWatch alarm is in the ALARM state.