Question: What causes the heart to miss a beat now and then? Is it dangerous?
If a piece of heart muscle is taken from the body and kept alive in a nutrient solution, it will spontaneously contract at about 40 beats per minute.
There is an area near the top of the heart that is made from a complex network of nerves. This is the natural pacemaker of the heart, and it sends electrical signals to the heart muscle to contract at faster rate of approximately 70 beats a minute. This pacemaker is itself controlled by nerves running to the brain, so that anxiety and exercise can cause the heart to beat faster. Certain chemicals in the blood stream can also act on the pacemaker, and the heart muscle itself, to alter the rate at which the heart contracts. It is therefore a very complex process. The occasional dropped (missed) heart beat is due to a blockage of the nerve signal to the heart muscle, a lack of signal from the pacemaker, chemical disturbances in the body and many other factors. Alcohol, smoking, drugs, caffeine, high blood pressure and several diseases can all cause missed heart beats.
If the dropped beats occur only once every minute or so, there is no cause for concern, as this is a common phenomenon, particularly in older people. If you find that every third or fourth beat is being missed, you should be under regular medical care and probably on medication. Patients with problems within these extremes should discuss the matter further with their doctor. S/he will almost certainly perform an ECG (heart electrical test) and probably order blood tests to exclude any serious disease. The treatment will depend on the result of these tests.
Missed heart beats are not in themselves dangerous, unless they become very frequent.

Question: I am concerned about the occasional irregular heartbeat I get for no apparent cause. It happens about once a week for just two or three beats. I am a woman in my 20s and would like to know what it could be.
There is a remote possibility that you may have a conduction abnormality in your heart, and to exclude this you should have an electrocardiograph performed by your family doctor.
By far the most likely reason for your occasional irregular heart beat is a condition known as paroxysmal atrial tachycardia (PAT). This is a very common problem, but is usually more annoying than serious. It is far more common in women than in men, and tends to occur at certain times of the month—usually just before a period. In some women the rapid heartbeats can last for an hour or two, and be quite distressing. In these cases, medication can be prescribed on a regular basis to prevent the problem. Most cases are similar to yours—a rapid pulse for just a few seconds or minutes.
Provided your medical check-up is normal, you can be reassured that there is nothing to be concerned about.

Question: My heart keeps jumping! Every few minutes it gives a funny beat. How can I stop this?
Everyone has extra heart beats at some time or other, and they cause no problems. If it becomes a frequent occurrence, it may be annoying, but is not normally serious. The first step is to have a cardiograph (ECG) done by your GP to demonstrate the type of abnormal beat, and possibly its cause. After this you may merely be reassured, or medication can be prescribed to prevent the extra beats. Unfortunately, this medication does not cure, only control, so it may have to be taken for many years.
The heart rate is determined by a pacemaker at the top of the heart. The pacemaker usually slows the heart down, as the heart would beat much faster if the pacemaker were disconnected. If you exercise, the inhibiting effect of the pacemaker is reduced, and then the opposite effect may be applied to speed the heart rate even further if you exercise very vigorously. At times, the natural tendency of the heart to beat faster than the pacemaker wishes can break through, and an extra, premature beat occurs, which you feel as a jump in your heart.