Unreadable / Noisy Vs. Supraventricular Tachycardia (Sustained) on Your Watch ECG

Unreadable Noisy SVT ECG
Qaly Heart
Qaly is built by Stanford engineers and cardiologists, including Dr. Marco Perez, a Stanford Associate Professor of Medicine, Stanford Cardiac Electrophysiologist, and Co-PI of the Apple Heart Study.

Key Takeaways

Got other questions on Noise or SVT? See the Qaly guides on Noise and SVT:

Introduction

Electrocardiograms (ECGs) are essential tools for monitoring heart health and detecting heart disorders. As technology has progressed, these valuable tools have become more accessible, and now it's possible to track your heart rhythms with an ECG on your watch. In this context, we’ll explore two ECG readings: an unreadable or "noisy" ECG and sustained supraventricular tachycardia (SVT). The comparison between noisy ECG vs SVT is important to help distinguish normal from abnormal rhythms. Let’s dive in.

What’s an Unreadable / Noisy ECG?

A noisy ECG is often marked by irregular, inconsistent waveforms that make it challenging to decipher the underlying heart rhythm. This could be due to external factors, such as movement or electrical interference, or internal factors, such as a low battery or malfunctions in the ECG's hardware or software.

Unreadable ECG recorded on a Samsung Watch.
Unreadable ECG recorded on a Samsung Watch.

Unreadable ECG recorded on a KardiaMobile.
Unreadable ECG recorded on a KardiaMobile.

The unreadable or noisy ECG trace on your watch may appear chaotic, without clear P waves, QRS complexes, or T waves, making it difficult to distinguish any regular rhythm.

What’s Supraventricular Tachycardia (SVT)?

SVT is an abnormal fast heart rhythm starting in the upper chambers (atria) of the heart, leading to a heart rate often between 150 to 250 beats per minute.

SVT read on an Apple Watch ECG through the Qaly app.
SVT read on an Apple Watch ECG through the Qaly app.

On an ECG, SVT is identified by a rapid, regular rhythm with typically narrow QRS complexes. Often, P waves are difficult to see. “Non-sustained” SVT lasts less than 30 seconds, whereas “sustained” SVT lasts longer, sometimes even up to several hours. Here’s more on what SVT looks like on your watch ECG.

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SVT read on a Kardia ECG through the Qaly app.
SVT read on a Kardia ECG through the Qaly app.

What’s the Difference Between an Unreadable / Noisy ECG and SVT?

The key differences between a noisy ECG and sustained SVT are apparent in their ECG patterns and the implications for health.

In terms of ECG patterns, a noisy ECG is characterized by chaotic, irregular waveforms, while sustained SVT presents regular, narrow complexes with a rapid rate. This distinct pattern in SVT helps differentiate it from the irregular waveforms of a noisy ECG.

In terms of health implications, a noisy ECG generally doesn't indicate a heart condition but rather technical issues affecting the ECG recording. On the other hand, sustained SVT is a potentially serious heart condition that may require immediate medical intervention. Symptoms can include palpitations, chest pain, shortness of breath, and in severe cases, loss of consciousness.

While a noisy ECG may cause concern due to its unreadability, it's important to understand that this is usually a technical issue rather than a sign of a heart condition. Conversely, SVT is a genuine medical condition that needs prompt attention.

In conclusion, understanding these rhythms – noisy ECG vs SVT – and their differences is crucial for effective heart rhythm monitoring. With the advent of watch ECGs, it's now easier than ever to keep track of your heart health. Always consult a healthcare professional if you have any concerns about your heart rhythms or ECG readings. Stay informed, stay proactive, and stay heart healthy!

Still Not Sure if It’s Unreadable / Noisy or Supraventricular Tachycardia (Sustained) on Your ECG?

Differentiating between a noisy ECG and SVT on your ECG can be tricky. If you’re still looking for help interpreting your ECG further, check out the Qaly app on App Store or Play Store. On Qaly, human experts will interpret your ECGs within minutes, day or night. Try out the Qaly app for free today!

Wondering if it's Unreadable / Noisy or SVT? On the Qaly app, human experts will interpret your ECGs for Unreadable / Noisy and SVT within minutes. Get started for free today.

Try free, cancel any time
Try Qaly for Free
App Store - Download Qaly | ECG Reader
Try Qaly for Free
Google Play - Download Qaly | ECG Reader
Try Qaly for Free
3 days free, cancel any time
QALY app - ecg reviews, ecg reader, ecg interpretations, review your ecg

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Wondering if it's Unreadable / Noisy or SVT? On the Qaly app, human experts will interpret your ECGs for Unreadable / Noisy and SVT within minutes. Get started for free today.

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