Premature Atrial Contraction (Single) Vs. Sinus Pause <3 Seconds on Your Watch ECG

PAC Sinus Pause 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 PAC or Sinus Pause <3 Seconds? See the Qaly guides on PAC and Sinus Pause <3 Seconds:

Introduction

Electrocardiograms (ECGs) are an essential part of heart health, measuring the electrical activity of the heart to identify different rhythms. In this article, we’ll discuss two such rhythms that you may encounter on your watch ECG: premature atrial contraction (single) and sinus pause of less than 3 seconds. We’ll be discussing these rhythms in the context of PAC vs sinus pause to give a detailed understanding of each, along with their key differences and health implications. Let’s dive in.

What’s a Premature Atrial Contraction (PAC)?

Premature atrial contractions are early beats that originate from the atria — the upper chambers of the heart. When multiple PACs occur, they appear as irregular early beats on an ECG. While occasional PACs are usually benign, frequent PACs can sometimes indicate underlying heart disease or trigger other arrhythmias. 

PAC read on a Fitbit ECG through the Qaly app.
PAC read on a Fitbit ECG through the Qaly app.

On an ECG, PACs are identified by an early and often different-looking P wave, followed by a QRS complex and a compensatory pause. Here’s more on what a PAC looks like on your watch ECG.

PAC read on a Samsung Watch ECG through the Qaly app.
PAC read on a Samsung Watch ECG through the Qaly app.

What’s Sinus Pause?

On the other hand, a Sinus Pause, also known as sinus arrest, is an event where the sinus node, which normally sends electrical impulses to trigger regular heartbeats, fails to fire, leading to a pause in the heart's electrical activity. When the pause is less than 3 seconds, it may not cause symptoms but will still appear on an ECG as a break in the P wave progression. Here’s more on what sinus pause <3 seconds looks like on your watch ECG.

Sinus Pause <3 Seconds read on a Kardia ECG through the Qaly app.
Sinus Pause <3 Seconds read on a Kardia ECG through the Qaly app.


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Sinus Pause <3 Seconds read on an Apple Watch ECG through the Qaly app.
Sinus Pause <3 Seconds read on an Apple Watch ECG through the Qaly app.

What’s the Difference Between PAC and Sinus Pause?

When comparing PAC vs sinus pause, the key difference lies in their basic nature. While a PAC represents an early, extra heartbeat, a sinus pause is a momentary halt in the heart's rhythmic beating. This distinction is visible on an ECG, with PAC showing an early P wave and sinus pause displaying a missing P wave.

Both PAC and sinus pause under 3 seconds can be asymptomatic in many individuals. However, some people may experience sensations like skipped or missed heartbeats. The health impact largely depends on the frequency and underlying cause. Both conditions could indicate other heart conditions or can occur due to lifestyle factors like stress, caffeine intake, or certain medications.

Remember, while personal ECG devices like a watch ECG can help monitor your heart rhythm, they do not replace professional healthcare consultations. If these rhythms appear on your device, it's crucial to seek medical advice for accurate diagnosis and treatment. Understanding the differences between PAC vs sinus pause can empower you to manage your health, but it should always be accompanied by professional medical advice. Stay informed, stay proactive, and stay heart healthy!

Still Not Sure if It’s Premature Atrial Contraction (Single) or Sinus Pause <3 Seconds on Your ECG?

Differentiating between a single PAC vs sinus pause <3 seconds 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 PAC or Sinus Pause <3 Seconds? On the Qaly app, human experts will interpret your ECGs for PAC and Sinus Pause <3 Seconds within minutes. Get started for free today.

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App Store - Download Qaly | ECG Reader
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Wondering if it's PAC or Sinus Pause <3 Seconds? On the Qaly app, human experts will interpret your ECGs for PAC and Sinus Pause <3 Seconds within minutes. Get started for free today.

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