ECG data analysis on the intervals each monitor reports

An electrocardiogram (ECG) monitor or patch measures its own intervals from the trace: PR, QRS, QT and the corrected QT (QTc). Kymolog records each interval it reports as a coded value in milliseconds, with the heart rate and rhythm label beside it.

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QTc · LOINC 8636-3 · ms · FHIR R4

Fig. 1. The last beat on the rhythm strip, its QT interval measured and coded as QTc.

Intervals in milliseconds, each with its own code

At 08:05 a monitor at bed W1-4 reports QTc 438 ms, QT 400, PR 160, QRS 92 and a heart rate of 72. The Kymolog™ edge agent files them as one panel in FHIR R4 (Fast Healthcare Interoperability Resources, release 4). Each interval is a coded component of that panel.

QTc carries LOINC 8636-3, Q-T interval corrected, and the uncorrected QT carries 8634-8, so the two never share a row. The correction formula is the monitor's setting; Kymolog stores the QTc it reports beside the QT and heart rate it came from. The panel also carries the rhythm label, such as atrial fibrillation.

Bedside monitors and wearable patches report through the same mapping. A patch measures its intervals from the few leads it records, not from a 12-lead ECG, and Kymolog files them under the same codes.

Example reading: QTc 438 ms

ECG intervals as coded ObservationsOne heartbeat and the start of the next, drawn on ECG recording paper, with calipers marking the PR interval (160 ms), the QRS duration (92 ms), the QT interval (400 ms) and the R-R interval (833 ms, a heart rate of 72 per minute). Beside the strip, the intervals as the monitor reports them, each a coded value with its LOINC code and UCUM unit: QTc, LOINC 8636-3, 438 ms, in red; QT, LOINC 8634-8, 400 ms; PR, LOINC 8625-6, 160 ms; QRS, LOINC 8633-0, 92 ms; heart rate, LOINC 8867-4, 72 /min.PR 160 msQT 400 msQRS 92 msR-R 833 ms, 72 /minCODED VALUESINTERVALLOINCVALUEUNITQTc8636-3438msQT8634-8400msPR8625-6160msQRS8633-092msHR8867-472/minEach value carries its LOINCcode and its UCUM unit.
ECG intervals as coded ObservationsOne heartbeat and the start of the next, drawn on ECG recording paper, with calipers marking the PR interval (160 ms), the QRS duration (92 ms), the QT interval (400 ms) and the R-R interval (833 ms, a heart rate of 72 per minute). Beside the strip, the intervals as the monitor reports them, each a coded value with its LOINC code and UCUM unit: QTc, LOINC 8636-3, 438 ms, in red; QT, LOINC 8634-8, 400 ms; PR, LOINC 8625-6, 160 ms; QRS, LOINC 8633-0, 92 ms; heart rate, LOINC 8867-4, 72 /min.PR 160 msQT 400 msQRS 92 msR-R 833 ms, 72 /minCODED VALUESINTERVALLOINCVALUEUNITQTc8636-3438msQT8634-8400msPR8625-6160msQRS8633-092msHR8867-472/min
Figure 2 as a table
IntervalLOINCLong nameValueUCUM unit
QTc8636-3Q-T interval corrected438ms
QT8634-8Q-T interval400ms
PR8625-6P-R Interval160ms
QRS8633-0QRS duration92ms
Heart rate8867-4Heart rate72/min
Fig. 2. The intervals an ECG monitor measures, each filed as a coded value: the LOINC code says which interval it is, and the UCUM unit, ms or /min, is stored with the number. QTc is the corrected QT.

ECG intervals into the EHR

Before each dose of a QT-prolonging drug, a telemetry nurse measures QT with calipers on a printed strip and types the number into the flowsheet. Kymolog files the monitor's own intervals instead. It finds the patient from the bed, applies the review step set for ECG monitors, and splits the panel into one result per interval.

ECG integration of this kind puts the numbers clinicians act on into the chart, each in its own flowsheet row with its time. Results reach the seven EHRs we deliver to as FHIR R4 Observations or HL7 v2 ORU messages.

ECG intervals into the EHRAn ECG monitor at bed W1-4 sends one panel at 08:05 with five coded components: QTc 8636-3, 438 ms, in red; QT 8634-8, 400 ms; PR 8625-6, 160 ms; QRS 8633-0, 92 ms; heart rate 8867-4, 72 /min. Kymolog matches the panel to Patient/p-041 by the bed, holds it for review or sends it straight in as set for the device type, and splits it into one result per interval. In the patient's EHR flowsheet the five rows show the 08:05 values beside the 07:05 values: QTc 430 then 438 ms, QT 398 then 400 ms, PR 162 then 160 ms, QRS 90 then 92 ms, heart rate 70 then 72 /min.ECG PANEL, 08:05QTc8636-3438msQT8634-8400msPR8625-6160msQRS8633-092msHR8867-472/minKymologpatient found by bed W1-4review step per device typeone result per intervalEHR FLOWSHEET, ECG07:0508:05QTc ms430438QT ms398400PR ms162160QRS ms9092HR /min7072
ECG intervals into the EHRAn ECG monitor at bed W1-4 sends one panel at 08:05 with five coded components: QTc 8636-3, 438 ms, in red; QT 8634-8, 400 ms; PR 8625-6, 160 ms; QRS 8633-0, 92 ms; heart rate 8867-4, 72 /min. Kymolog matches the panel to Patient/p-041 by the bed, holds it for review or sends it straight in as set for the device type, and splits it into one result per interval. In the patient's EHR flowsheet the five rows show the 08:05 values beside the 07:05 values: QTc 430 then 438 ms, QT 398 then 400 ms, PR 162 then 160 ms, QRS 90 then 92 ms, heart rate 70 then 72 /min.ECG PANEL, 08:05QTc8636-3438msQT8634-8400msPR8625-6160msQRS8633-092msHR8867-472/minKymologpatient found by bed W1-4review step per device typeone result per intervalEHR FLOWSHEET, ECG07:0508:05QTc ms430438QT ms398400PR ms162160QRS ms9092HR /min7072
Figure 3 as a table
IntervalLOINCUnit07:0508:05
QTc8636-3ms430438
QT8634-8ms398400
PR8625-6ms162160
QRS8633-0ms9092
Heart rate8867-4/min7072
Fig. 3. One ECG panel becomes five rows in the chart. Kymolog finds the patient from the bed, applies the review step set for the device type, and files each interval as its own coded result at the time the monitor measured it.

Bring the monitor class your telemetry unit uses and the EHR it charts in. The demo splits one ECG panel into interval rows in a test chart.

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QTc monitoring from coded intervals

Clinicians and studies read QTc as a change from the patient's own earlier values. Each QTc Kymolog files keeps its measurement time and its device. Readings such as 430 ms at 07:05 and 438 ms at 08:05 then stay in order across a shift on telemetry or the visits of a trial.

Kymolog stores the uncorrected QT and the heart rate beside each QTc. A study that prefers another correction formula can recompute QTc from those two values, and every result still points back to the monitor that measured it.

ECG intervals for research

Every interval Kymolog files for the chart is also kept as a study row. The row holds the value, its LOINC code and the time the monitor measured it. It also names the encounter and the monitor, by serial number and by unique device identifier (UDI).

ECG clinical trials and drug-safety studies need that link from each QTc to a device and a time. Rhythm labels sit on the same rows, so an analysis can set aside hours of atrial fibrillation before it averages anything. Medication orders and diagnoses come from the EHR itself; Clinical Extract covers that side of a study.

Set up an ECG demo for your telemetry unit

Tell us which ECG monitors or patches your units use and which EHR they chart to. We will follow one QTc from the monitor to a flowsheet row and into a dataset. We reply within one business day with times to talk.

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