Heart Education

What Sinus Pause >3 Seconds Looks Like on Your Watch ECG

Sinus pause above 3 seconds on smartwatch ECG

Key Takeaways

Sinus pause >3 seconds is a type of heart rhythm disorder. It affects the heart's natural pacemaker (sinus node), which controls the heartbeat. It occurs when the sinus node stops for a short period, causing a delay in the heart’s activity.

How to Spot Sinus Pause >3 Seconds on Your Watch ECG?

The characteristic feature of sinus pause >3 seconds is that signals from the sinus node pause, causing skipped beats or a delay of activation in the atria for more than 3 seconds. To identify a sinus pause >3 seconds or sinus arrest, look for the following characteristics in your ECG:

  • P wave: same shape and upright in deflection but absent during pause.
  • PR interval: Each PR interval is the same, without any variations. 
  • QRS Complex: Each QRS duration and its morphology are the same, without any deviations from QRS complex to complex.
  • Length of pause: The pause length is measured from the R-R interval to calculate the distance of time for the pause by multiplying the number of boxes by 0.04 seconds. The pause of less than 3 seconds usually needs no investigation and may be seen in normal people; however, longer pauses (≥3 seconds) require further investigation and treatment.

Note: When sinus arrest reaches or exceeds 6 seconds, it is considered a medical emergency. 

A single-lead ECG smartwatch can determine the presence of a sinus pause of >3 seconds. It is essential to visit a doctor as soon as possible for a clinical diagnosis, including a complete, 12-lead ECG. In addition, you may find it helpful to record any symptoms when you record your smartwatch ECG, such as palpitations and what you were doing. This information will help your physician give you an accurate diagnosis.

Common Symptoms of Sinus Pause >3 Seconds

The seriousness of the pause depends on its length and duration. People with sinus pause >3 seconds will experience signs and symptoms of decreased cardiac output (bradycardia) if it occurs on a frequent basis. The pauses may also cause periods of ischemia (when cells are deprived of oxygen), hypotension (low blood pressure), dizziness, and syncope (loss of consciousness). However, common symptoms include:

  • A sensation of rapid, fluttering heartbeats (palpitations)
  • Chest pain or discomfort
  • Confusion
  • Dizziness or lightheadedness
  • Fainting or near fainting
  • Fatigue
  • Shortness of breath
  • Slower pulse (bradycardia

Any Cause for Concern?

Initially, sinus pause >3 seconds appears to be asymptomatic (without symptoms) and then develops signs and symptoms of low cardiac output. Therefore, it is important to observe frequently for signs and symptoms of low cardiac output. Notify a licensed practitioner of these signs or symptoms, and provide information about the frequency and length of pauses. They will require immediate treatment. Sinus arrest at or above 6 seconds is considered a medical emergency and requires emergency medical procedures. 

As always, if you show signs of a potential sinus pause over 3 seconds, contact your healthcare provider as soon as possible to rule out the presence of harmful underlying conditions.

Still Not Sure How to Spot Sinus Pause >3 Seconds on Your Watch ECG?

Your smartwatch can be your partner in looking after your heart. If you’re concerned about a sinus pause over 3 seconds, get your smartwatch ECGs analyzed by experts within minutes on the QALY app: iOS and Android.

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