# addHeartbeatWithTimeInterval(sinceSeriesStartDate:precededByGap:completion:) Adds a heartbeat to the series. ``` func addHeartbeatWithTimeInterval(sinceSeriesStartDate timeIntervalSinceStart: TimeInterval, precededByGap: Bool, completion: @escaping @Sendable (Bool, (any Error)?) -> Void) ``` ## Parameters `timeIntervalSinceStart` The time of the heartbeat, measured from the series builder’s start date. This must be a positive value. `precededByGap` A Boolean value that indicates whether this heartbeat was immediately preceded by a gap in the data, indicating that one or more heartbeats may be missing. `completion` The completion handler called by the builder after it attempts to add the heartbeat to the series. The completion handler takes the following parameters: - `success`: A Boolean value that indicates whether the builder successfully added the heartbeat. - `error`: If the `success` parameter is , this contains an object that describes the error; otherwise, `nil`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)