It's currently not possible to disable heartbeats, if you set a heartbeat value of 0 on the client side it will use the server's suggested value instead of disabling it (sending 0 to the server in the TuneOk frame).

https://github.com/squaremo/amqp.node/blob/6ee18f27e31863f5256bc921a21f36ebf2ba5e74/lib/connection.js#L192-L198