Love isn’t the only reason your heart can skip a beat. While abnormal heartbeats can be alarming, they are generally harmless. They happen for various reasons. Which types are common—and when should you be concerned?
Your heartbeat normally keeps a predictable pace: it speeds up when you’re active and slows down when you’re at rest. But many people notice strange sensations of the heart called heart palpitations at least once in a while. People usually say that it feels as if their heart has stopped beating, or is racing or pounding.
Cardiologist Alfred E. Buxton, MD, professor of medicine at Harvard Medical School, says, “A typical scenario is a person who feels like their heart is racing, but if you look at their electrocardiogram (ECG), it’s Totally normal.”
He added that people wearing smartwatches with heart rate monitors may have a greater awareness of normal heart rates. “People with a resting heart rate of 60 beats per minute are concerned when their heart rate rises to 90, but it’s still in the normal range,” he says.
The feeling that your heart has stopped beating also happens when the upper chambers of the heart (atria) or the lower chambers (ventricles) contract a little earlier than normal.
During the next beat, the atria pause briefly to return to normal rhythm. The lower chambers (ventricles) of the heart then forcefully squeeze out the excess blood that has accumulated during that pause. They may also contract earlier than normal, which can make you feel like your heart has stopped and started again.
Known as ectopic beats, both of these types of premature contractions can cause a rapid pounding sensation. However, there is nothing to worry about. Dr. Buxton says, “I often tell my patients that the fact that they feel these beats is usually a sign that their heart is healthy. A weak, diseased heart may not beat as loudly. “
AV block and bundle branch block
The electrical impulses tell your heart to pump. They travel through the right and left sides of your heart. But sometimes impulses travel more slowly than normal or irregularly, causing a condition called AV block. There are various degrees of AV block, some benign, others associated with extremely slow heart rates that can be dangerous.
Another electrical conduction abnormality is a bundle branch block. It results from an abnormal activation pattern of the ventricles that squeeze blood from the heart to the rest of the body. The most common is right bundle branch block, which usually does not cause obvious symptoms. This can be seen during an ECG, and reflects the gradual aging of the heart’s conduction system. However, sometimes a right bundle branch block occurs because of underlying damage from a heart attack, inflammation or infection of the heart, or high pressure in the pulmonary arteries.
A left bundle branch block may occur as an isolated event, or may be caused by a variety of underlying conditions. In some cases, left bundle branch block can lead to abnormal function of the left ventricle, a condition that is sometimes corrected by special pacemakers.
An electrical misfire in the atria can cause atrial fibrillation, a disorganized quivering of the atria that increases the risk of stroke. Commonly known as atrial fibrillation, this heart rate problem can come and go, lasting only a few minutes or sometimes for days or even longer. And while some people complain of fluttering in their chest or a fast, irregular heartbeat during an episode of atrial fibrillation, other people have no symptoms.
Some smartwatches that can record brief ECGs may be able to detect afib. But Dr. Buxton says they are not sensitive or specific enough to reliably diagnose the problem. “Sometimes the watch tells you you have atrial fibrillation when you don’t, or vice versa,” he says.
However, the heart rate monitoring feature can be helpful. In people younger than 65, the heart rate may be 170 beats per minute or higher during atrial fibrillation. But in those in their 70s and 80s, who are more likely to have atrial fibrillation, the heart rate is usually not that high.
When should you be concerned about an irregular heartbeat?
An irregular heartbeat, such as racing, fluttering or skipping a beat, is usually harmless. Even in cases when heartburn is frequent and bothersome (which is rarely the case), reassurance may be the only treatment needed.
But you should contact your doctor if you notice other symptoms along with an abnormal heartbeat, such as feeling
- Pain in chest
- Like you’re going to faint.
People who have been told they have bundle branch block may need an ECG from time to time to monitor their condition. They should also be alert for symptoms such as dizziness or fainting, which may occur if the blockage worsens or occurs on both sides and the heart rate decreases.