QALY | What Sinus Rhythm Looks Like on Your Watch ECG

Key Takeaways

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Sinus rhythm refers to the rhythm of your heartbeat, determined by the sinus node of your heart, your heart’s natural “pacemaker.” The sinus node creates an electrical pulse that travels through your heart muscle, causing it to contract or beat.

Normal sinus rhythm is the rhythm of a healthy heart! It means the electrical pulse from your sinus node is properly transmitted throughout the heart muscle. In adults, normal sinus rhythm usually accompanies a heart rate of 60 to 100 bpm. However, it’s possible for sinus rhythm to be faster or slower than this and still be considered normal.

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How to Spot Sinus Rhythm on Your Watch ECG

In normal sinus rhythm, the electrical impulse originates within the SA node and travels through the atria to the AV node. After a brief delay, the impulse travels down the bundle branches through the Purkinje fibers to the ventricles.

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It is categorized as sinus rhythm when each of the five steps of rhythm analysis is “normal.”

‍Rate: Normal (60-100 bpm)‍
Rhythm: Regular‍
P Wave: Normal (positive & precedes each QRS)‍
PR Interval: Normal (0.12-0.20 sec)‍
QRS: Normal (0.08-0.12 sec)

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Sinus Rhythm on smartwatch ECG (Apple Watch, Kardia, Samsung, Fitbit) — Example of Sinus Rhythm caught with Apple Watch

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Sinus rhythm recorded with Kardia and reviewed with QALY — Example of Sinus Rhythm recorded with Kardia. Notice artifact at the beginning of the recording.

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Sinus rhythm recorded with Apple Watch ECG. Reviewed with QALY. — Example of Sinus Rhythm recorded with Apple Watch.

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Sinus Rhythm caught with Apple Watch, PQRST calculated with QALY app

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The Difference Between Sinus Rhythm and Heart Rate

While similar, sinus rhythm is a little different from heart rate. Your heart rate is the number of times your heart beats in a minute. A resting heart rate of 60 to 100 beats per minute (bpm) is considered normal for most people. However, your heart rate can be either faster or slower than this, depending on the demands placed on your heart as well as other underlying health conditions.

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Sinus rhythm, on the other hand, refers to the pattern of your heartbeat. It corresponds to the rate at which electrical pulses are sent out from the sinus node. When these pulses are sent out at a normal rate, it’s referred to as normal sinus rhythm.

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As you can probably see, sinus rhythm and heart rate are linked. Electrical pulses must first be generated by the sinus node (sinus rhythm). As these pulses travel through the heart muscle, they cause it to beat (heart rate). Because of this, sinus rhythm often aligns with your heart rate.

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Any Cause for Concern?

None! Sinus rhythm is perfectly normal and healthy.

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Still Not Sure How to Spot Sinus Rhythm on Your Watch ECG?

Your smartwatch can be your partner in looking after your heart. If you need help identifying sinus rhythm, get your smartwatch ECG analyzed by experts within minutes on the QALY app: iOS and Android.

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