What actually happened
Cardiogram's App Store listing no longer resolves — a lookup against Apple's own catalogue returns no result, which is what a delisted app looks like. Reporting through 2025 described the company being acquired, the acquirer failing, the assets changing hands again and the remaining team going, with the service going dark late in the year.
We can state the first part as fact because it is checkable in thirty seconds. The corporate history we would treat as reported rather than confirmed. Either way the practical position is the same: you cannot install it.
Watch for a name collision. There is a separate, unrelated app called Cardiogram - HR Monitor by an individual developer, still on the App Store as a paid download. It is not the Cardiogram most people mean, and it is not a continuation of it.
Your data is probably fine
This is the part worth knowing before you panic about years of history.
On iPhone, Cardiogram read from Apple Health rather than being the system of record. Heart-rate samples written by an Apple Watch live in Health, on your device, and they are still there whether or not the app that displayed them exists. Any replacement that reads HealthKit picks up the same history — you are changing the window, not the data.
What does not survive is anything Cardiogram computed and stored on its own servers: its scores, its tagging, and any analysis that was not written back to Health. That is the real cost of a service shutting down, and it is the argument for preferring apps that keep their working data on the device.
What to check in a replacement
Does it read from Apple Health? If yes, your existing history appears immediately. If it insists on collecting fresh data only, you start from zero.
Where does it keep what it derives? An app that syncs everything to its own account will take that with it if it ever shuts down, exactly as happened here. One that processes on the device leaves you with Health, which is not going anywhere.
Is it a subscription? Cardiogram was. That is not a reason to avoid subscriptions, but it is worth noticing that the thing you lost was something you were paying for.
Where 70 BPM fits
We make 70 BPM, so treat this as disclosure rather than a recommendation. It reads heart-rate samples from Apple Health and lays them against your calendar, so you can see which meetings and blocks your body reacted to rather than a number in isolation. Its listing states that processing stays on the iPhone and that it does not upload your heart rate to a cloud. It is free and iPhone-only.
It is deliberately narrower than Cardiogram was — there is no cross-platform wearable support, no web dashboard and no clinical scoring. If those were the parts you relied on, this is not a like-for-like replacement and it would be dishonest to present it as one.