Sinus Rhythm Vs. Premature Atrial Contraction (Single) on Your Watch ECG

Sinus Rhythm PAC 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 Sinus Rhythm or PAC? See the Qaly guides on Sinus Rhythm and PAC:

Introduction

Understanding heart rhythms is a critical aspect of heart health, a task made easier with the advent of wearable technology that can track electrocardiograms (ECG) right on your wrist. This article will delve into a comparison of two such rhythms, the sinus rhythm and single premature atrial contraction (PAC), providing insights into the differences between premature atrial contraction vs sinus rhythm. Let’s dive in.

What’s Sinus Rhythm?

Sinus rhythm, or normal sinus rhythm, is considered the standard rhythm of a healthy heart. In this pattern, electrical signals originate from the sinoatrial (SA) node located in the right atrium, initiating each heartbeat and ensuring they occur at a steady, regular rate.

Sinus Rhythm read on a Samsung Watch ECG through the Qaly app.
Sinus Rhythm read on a Samsung Watch ECG through the Qaly app.

On an ECG, sinus rhythm is characterized by a distinct P wave (indicating atrial contraction) followed by the QRS complex (signifying ventricular contraction), then the T wave (representing ventricular relaxation). This cycle repeats at a rate of 60-100 times per minute in adults at rest. Here’s more on what sinus rhythm looks like on your watch ECG.

Sinus Rhythm read on a Fitbit ECG through the Qaly app.
Sinus Rhythm read on a Fitbit ECG through the Qaly app.

What’s a Premature Atrial Contraction (PAC)?

On the other hand, 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 Watch ECG through the Qaly app.
PAC read on a Fitbit Watch ECG through the Qaly app.


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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 the Difference Between Sinus Rhythm and PAC?

When comparing sinus rhythm with PAC vs PVC, or in this case, a single PAC, the most evident difference is the disruption of the regular rhythm in PACs. Sinus rhythm presents as a regular, orderly pattern, while a PAC introduces an irregularity with an early P wave.

On the ECG, sinus rhythm is characterized by regular and distinct P waves, QRS complexes, and T waves. In contrast, a premature atrial contraction vs sinus rhythm presents an early P wave, usually followed by a QRS complex.

In terms of health impact, a normal sinus rhythm is indicative of a healthy, well-functioning heart. Single PACs, on the other hand, are usually benign and often go unnoticed. However, frequent PACs or those associated with other heart diseases may warrant medical attention.

In conclusion, understanding the nuances between sinus rhythm and a single PAC can be an empowering tool in managing your heart health, especially with the use of a watch ECG. But remember, these devices are not a replacement for professional medical advice. Always consult with a healthcare provider if your watch ECG detects any irregularities for a comprehensive evaluation and diagnosis. Stay informed, stay proactive, and stay heart healthy!

Still Not Sure if It’s Sinus Rhythm or Premature Atrial Contraction (Single) on Your ECG?

Differentiating between sinus rhythm vs PAC 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 Sinus Rhythm or PAC? On the Qaly app, human experts will interpret your ECGs for Sinus Rhythm and PAC within minutes. Get started for free today.

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Try Qaly for Free
App Store - Download Qaly | ECG Reader
Try Qaly for Free
Google Play - Download Qaly | ECG Reader
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QALY app - ecg reviews, ecg reader, ecg interpretations, review your ecg

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Wondering if it's Sinus Rhythm or PAC? On the Qaly app, human experts will interpret your ECGs for Sinus Rhythm and PAC within minutes. Get started for free today.

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