Normally, the heartbeat starts in an area in the heart's upper chambers (atria). This area is the heart's natural pacemaker. It is called the sinoatrial node or SA node. Its role is to keep the heartbeat steady and regular.
In a sinus pause of less than 3 seconds, the action of the sinoatrial (SA) node fails, causing the underlying heart rhythm to pause or stop 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 a sinus pause is a temporary interruption in your heart's normal sinus rhythm. This "pause" is caused by a failure of your heart to generate an electrical impulse within the SA node, causing your heart to pause for less than 3 seconds. Here are some of the following characteristics that’ll help you spot a sinus pause on your watch ECG:
- P wave: present in underlying rhythm but absent during pause.
- PR interval: normal or prolonged.
- QRS Complex: usually narrow.
- Rate: underlying rhythm may vary but is generally slow to normal.
- 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.
Common Symptoms of Sinus Pause <3 Seconds
Sinus pause of less than 3 seconds doesn’t typically require investigation, and it’s seen in otherwise healthy people. However, longer pauses (≥3 seconds) require further investigation and treatment.
The following are the common symptoms of sinus pause of less than 3 seconds:
- Chest pain or discomfort
- Slow heart rate
- Dizziness or lightheadedness
- Shortness of breath
Any Cause for Concern?
No clinical intervention is typically required when pauses in sinus rhythm are brief — under 3 seconds. Sometimes, it can be managed with simple medication and dietary changes.
As always, if you show signs of a potential sinus pause under 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 under 3 seconds, get your smartwatch ECGs analyzed by experts within minutes on the QALY app: iOS and Android.
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