What causes heart palpitations or temporary irregular heartbeats? Sometimes while resting I can feel my heart skip a beat and it feels, when it beats again, like it’s flipping over in my chest. I never feel any pain from this but I do feel afraid, especially when it happens for a minute or two. Is this dangerous?
Palpitations can have many different causes, and making an accurate diagnosis requires catching one of the irregular heartbeats on an electrocardiogram (EKG). However you describe the sensation caused by one of the most common and benign irregular beats, the premature atrial contraction.
Our heartbeats begin in a small group of specialized cells called the sinus node, located in the wall of the left atrium, the chamber of the heart above the left ventricle. The impulse from the sinus node spreads through the atria, causing them to contract, and then after a small delay, spreads through the ventricles, causing them to contract. The heartbeat we feel is the ventricular contraction, rather than the small atrial contraction a fraction of a second before.
An arrhythmia, which is any alteration of the normal heart rhythm, can produce extra beats, more rapid beats, irregular beats, or slower beats. All of these may have different causes and require an EKG for accurate diagnosis. The EKG measures the actual flow of electricity that carries the impulse from the sinus node to the ventricles during each beat.
Extra beats can be either atrial premature beats or ventricular premature beats, depending on the origin of the impulse causing the extra beat. With atrial premature beats, there is a small pause before the next normal beat occurs, and it is this pause and the next normal beat that are felt by people. I often have them myself, and the description of the heart feeling like it flips over is very accurate.
When normal people are monitored by EKG for 24 hours, about 60 percent of them have some atrial and ventricular premature beats, so they are very common. Most people are unaware of the irregularity, but some people are more sensitive to it, and feel them as a brief palpitation. The palpitations do not indicate heart disease, and except in people known to have severe heart disease, such as someone recovering from a heart attack, they are not dangerous or life threatening. If the irregularity is very frequent or disturbing, it can be treated. Stopping all caffeine intake, which stimulates the palpitations, is often all that is necessary. It has stopped me from having them. If they persist, small doses of a beta-blocker medication will often clear them up.