Low Voltage Vs. Sinus Rhythm on Your Watch ECG

Got other questions on Low Voltage or Sinus Rhythm? See the Qaly guides on Low Voltage and Sinus Rhythm:

• What Low Voltage Looks Like on Your ECG
• What Sinus Rhythm Looks Like on Your ECG
• ‍How to Read an ECG: Stanford Cardiologist Explains
• ‍The Ultimate Cardiologist's Guide to the Smartwatch ECG

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Introduction

With the rise of wearable technology, electrocardiograms (ECGs) have become a crucial part of routine heart health monitoring. They allow us to record the electrical activity of the heart and detect various heart conditions. In this article, we will explore two ECG patterns: low voltage and sinus rhythm. Understanding the difference between low voltage vs sinus rhythm can help us comprehend our heart health better. Let’s dive in!

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What’s Low Voltage on an ECG?

In an ECG recording, voltage corresponds to the height and depth of the waves that represent the electrical activity of the heart. Each wave reflects a specific part of your heart’s cycle, and the size of the waves, or “amplitude,” can provide crucial information about your heart health.

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Low voltage on an ECG means that the amplitude of the waves on your ECG is lower than what is typically expected. Specifically, it's defined as a peak-to-peak QRS amplitude of less than 5mm in all limb leads or less than 10mm in all precordial leads. Your Apple Watch, Fitbit, Samsung, or other smartwatch ECG is a limb lead.

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On your ECG, low voltage may appear as consistently small or flat waves across the entire tracing. While it might be challenging to evaluate specific numeric values due to the often smaller and less detailed display on a smartwatch ECG, low voltage often looks like the overall ECG tracing is “smaller.”

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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.

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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.

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What’s the Difference Between Low Voltage and Sinus Rhythm?

When we compare low voltage vs sinus rhythm, we are essentially comparing a pattern (low voltage) with a rhythm (sinus rhythm). Low voltage refers to the amplitude of the heart's electrical signals, while sinus rhythm describes the regular pattern of heartbeats set by the SA node.

Low voltage can occur in any rhythm, including sinus rhythm. In other words, a sinus rhythm ECG can have low voltage if the heart's electrical signals are weak. It's important to note that a low voltage finding, while usually benign, could indicate underlying conditions affecting the heart's electrical signal strength.

On the other hand, sinus rhythm is the normal, healthy rhythm of the heart. Deviations from sinus rhythm could signify potential cardiac disorders like arrhythmias.

In conclusion, recognizing and understanding the differences and potential implications of ECG patterns and rhythms, such as low voltage and sinus rhythm, can greatly assist in proactive heart health management. Nevertheless, it's crucial to consult with healthcare professionals for comprehensive heart health assessments, as personal ECG devices should supplement, not replace, professional medical advice. Stay informed, stay proactive, and stay heart healthy!

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Still Not Sure if It’s Low Voltage or Sinus Rhythm on Your ECG?

Differentiating between low voltage vs sinus rhythm 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 today!