Specialties
In cardiology the exam depends on a device that must be handed out and returned
What does a cardiology queue look like?
The unit receives two distinct flows. One is the screening exams any specialty orders before surgery or inside a routine follow-up: the electrocardiogram is the pure example, cheap, fast and very high volume. The other is the studies a cardiologist orders inside a diagnostic sequence, and those arrive chained.
The chaining defines the unit. An echocardiogram is ordered because the ECG showed something; a cardiac stress test is ordered to complete the picture; and all of it ends in a follow-up where the cardiologist interprets the set. Every link that drops leaves the next one pointless and the last one without input.
A cardiology schedule that works keeps the sequence compressed: a patient's studies happen inside a window that lets the final follow-up be useful. One that does not work shows every exam performed and the cardiology follow-up empty, with the patient waiting on an interpretation nobody will give them.
What falls through here that falls through in no other unit?
The device has to come back. A Holter monitor and an ambulatory blood pressure monitor are worn studies: the unit hands over a device, the patient walks out wearing it, and returns the next day. Between those two moments the exam depends entirely on one person keeping a return appointment that no scheduling system models.
- The patient who misses the fitting leaves the device on the shelf and the next day's slot empty.
- The patient who takes the device and does not return it blocks everyone behind them on that list, one per day.
- A recording that comes back incomplete forces a repeat study, consuming another device-day.
- Two worn studies for the same patient rarely fit in one week, and the rule that separates them belongs to the unit.
None of those losses look like a classic no-show on a dashboard. What they consume is device-days, which is the unit's real scarce resource and the one nobody counts.
Why is an order that just says Holter a scheduling problem?
| What the order says | What the unit has to reserve | What happens if it picks wrong |
|---|---|---|
| Holter, nothing more | One of two different devices, with two durations and two queues. | The wrong device gets fitted and the study is repeated in full. |
| Ambulatory blood pressure monitoring | A blood-pressure monitor, with fitting and removal. | The patient returns with a study that does not answer the clinician's question. |
| Holter monitor | A rhythm recorder, with its own device availability. | A day of the unit's scarcest inventory gets consumed. |
The ambiguity comes from upstream. The ordering clinician writes the short name because in their head the clinical context disambiguates it, and that context does not travel with the exam order. Reading the whole order, including the diagnosis behind it, is what lets the unit reserve the right device the first time.
What preparation burden lands on the patient here?
Less than gastroenterology, with one important difference: here much of the preparation happens during the exam. A worn study asks the patient to live a normal day with a device attached, keep an activity diary and respect hygiene restrictions while wearing it. A stress test asks for suitable clothing, the ability to walk, and sometimes pausing something they have been taking.
When any of those conditions fails, the study is repeated. The unit logs it as an exam performed and the patient rejoins the queue, so the throughput indicator rises while the care gap stays open.
What each study requires is defined by your site's protocol and changes between locations. This page does not publish it, and your unit should not be discovering it on a website.
What should the unit measure?
Cardiology is where the standard indicator misleads the most, because the exam and the care come apart. Every one of a patient's studies can be performed without closing any of the clinical loops that produced them.
- Share of complete chains: patients whose study ended in a follow-up with an interpretation.
- Device-days lost to missed fittings or late returns.
- Studies repeated for incomplete recordings, counted separately from throughput.
- Time between the study and the follow-up that interprets it.
The second indicator almost never exists and it moves the most money in this unit. There is Chilean evidence consistent with the fourth: the University of Chile study that quantified missed specialist appointments in 2022 found that follow-up visits are missed more often than first consultations across every specialty measured. The link that closes the loop is the most fragile one in the chain.
The general framework, with the denominator and the control group stated, is in how we measure.
What changes when someone follows the whole chain?
The unit moves from managing loose exams to managing patients with an open sequence. That means the device return gets a reminder, a missed fitting gets re-offered the same day, and the final follow-up is booked with the result already available.
It is one of the units where the effect shows up fastest, because the device inventory is small and every freed device-day is visible in next week's queue. The device is the schedule.