Yes, 心臓診断 is free to download, however it contains in-app purchases or subscription offerings.
Not enough reviews to make a reliable assessment. The app needs more user feedback.
心臓診断 has several in-app purchases/subscriptions, the average in-app price is ¥375.00.
To get estimated revenue of 心臓診断 app and other AppStore insights you can sign up to AppTail Mobile Analytics Platform.