I’m doing some reading about the Zio patch. In one of the studies, the researchers report that:
“Over half our patients (53.4%) did not have an arrhythmia despite a triggered event. This allows the clinician to potentially exclude an arrhythmia as an etiology of the patient’s symptoms and potentially avoid further cardiac evaluation.” (Ambulatory Cardiac Monitoring for Discharged Emergency Department Patients with Possible Cardiac Arrhythmias)
A “triggered event” is a self-recorded symptom report that involves, at minimum, pressing a button on the top of the Zio device. (In the current system, it may also include a written note in an app or notebook.) I’m not totally clear on whether my particular type of arrhythmia, as diagnosed by my cardiologist from the Kardia ECG data, would have been counted as an arrhythmia during this earlier study. The list of arrhythmia types is below:
- Ventricular tachycardia (≥4 but <8 beats):
- Ventricular tachycardia (≥8 beats):
- Pause (>3 seconds):
- AV block (2nd degree Mobitz II or 3rd degree): Supraventricular tachycardia (≥4 but <8 beats): Supraventricular tachycardia (≥8 beats):
- All atrial fibrillation:
- Chronic atrial fibrillation:
- Paroxysmal atrial fibrillation: Torsades/Ventricular fibrillation
These are all serious arrhythmia events, and as far as I can tell premature ventricular contractions with pause of under 3 seconds is not included. Looking roughly at my own data, I do not think that the pause between my heartbeats when I experience PVCs is greater than 3 seconds. My typical heart rate is between 60-70 bpm, and my typical PVC symptoms involve a delayed beat, then a feeling of flutter, then a regular beat. When this happens many times in a row, I feel pretty bad and my Sp02 drops. But I haven’t noticed pauses of over 3 seconds, which for me would be very long. In the study listed, the patients with serious arrhythmias are experiencing stronger symptoms than I am.
A couple questions:
- If anybody recognizes an error in how I’m thinking about this, will you let me know? Maybe my take on the reported arrhythmias from the earlier Zio studies is incorrect.
- If my take is correct, then I wonder if the data reported from my current period wearing the patch will show my particular kind of PVCs. The Kardia device did not identify these PVCs as a specific event, but rather reported ambiguous non-normal results that required the cardiologist to interpret. I suspect that Zio analytics have improved in many ways in the years since this study, and can now give a quantitative assessment of PVCs of my type. Glad to hear anything about this, though I will also know once the data is visible.
I haven’t recorded any arrhythmias yet today on my 1-Button tracker.