In this note, we study the output synchronization problem of networked passive systems with event-driven communication, in which the information exchange among the coupled agents are event-based rather than pre-scheduled periodically. We propose a setup for the interconnected agents to achieve output synchronization with event-driven communication in the presence of constant communication delays. The results presented here are important extensions of applying event-driven communication to control of multi-agent systems, especially when it is difficult to derive a common upper bound on the admissible network induced delays, or when the network induced delays between coupled agents are larger than the inter-event time implicitly determined by the event-triggering condition.