Similarly, palpitations can sometimes be due to a normal physiologic response such as when one is exercising rigorously and the heart is, in fact, pumping very hard and rapidly. It can occur when one is nervous, anxious, afraid or excited (almost everyone has experienced this at some time or another) and in those situations, it is not considered abnormal. Occasionally, people can have a propensity to abnormal amounts of anxiety such as with panic disorder leading to recurrent palpitations as well as chest pains and shortness of breath. One can have palpitations in these situations even with no increase in heart rate. The sensation of palpitations is real to the person but it might not indicate a problem with the heart. However, as palpitations can be due to a true cardiac arrhythmia, these symptoms often appropriately prompt a medical evaluation.
A cardiac arrhythmia is a condition caused by a problem with the heart’s electrical system. These abnormal rhythms may make the heart pump less efficiently. It can be a pure “electrical” problem of the heart where the heart structurally otherwise is healthy and normal but arrhythmias can also occur with underlying heart disease as well.
Many arrhythmias do not have a known cause. However, there are various factors that can contribute to arrhythmias. These include heart disease, high blood pressure, diabetes, smoking, excessive alcohol consumption, and stress. It is known that some substances, including certain over-the-counter and prescription medications, nutritional supplements, and herb-based remedies, cause arrhythmias in some people. Prescription medications can also contribute to the appearance of arrhythmias.
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Fast heart rate symptoms and treatments
A heart rate of over 100 beats per minute is called tachycardia. It can produce palpitations (a feeling in the chest that the heart is pounding or beating very fast), chest pain, dizziness, swooning and fainting if the heart beats too fast for the blood to circulate well. The heartbeats may have a regular or irregular rhythm.
When the fast heartbeat begins in the ventricles, what is called ventricular tachycardia (v tach), it may interfere with the heart’s ability to pump enough blood to the brain and other vital organs. This type of arrhythmia can quickly degenerate into ventricular fibrillation (v fib). Ventricular fibrillation is the most serious heart rhythm alteration and left untreated is fatal. In v fib, the ventricles tremble and the heart does not pump any blood. Death occurs quickly (sudden cardiac death) unless immediate medical intervention is performed. If treated in time, ventricular tachycardia and ventricular fibrillation sometimes can revert to a normal rhythm with an electrical shock using a defibrillator. An effective way to treat these potentially fatal rhythms in someone felt to be at increased risk of developing these arrhythmias, is through the use of an electronic device called an implantable cardiac defibrillator (ICD). Fast heart rhythms can be controlled with medications or identifying and destroying the source of the rhythm alterations.
When fast heartbeats begin in the atria, it is termed a supraventricular tachycardia (SVT). Reentrant tachycardia occurs when there is a “short-circuit” of electrical signals between the atria and ventricles. Normally, the only way that signals go between the atria and ventricles is through the AV node. If there is another electrical pathway between the atria and ventricles, a “closed circuit” may occur, in which the electrical current travels quickly over and over again through the short circuit and the AV node which produces a very rapid heart rate. These SVT’s sometimes can be controlled with medications. Sometimes they can even be cured by using electrical catheters threaded up into the heart to map out the abnormality, and then, using a focused small amount of energy, ablating the abnormality (an ablation).
In atrial fibrillation, the atria tremble instead of beating efficiently. The atria beat at over 300 beats per minute. This reduces the heart’s efficiency because less blood flows through the atria toward the ventricles. Some people can have no symptoms at all and others can have palpitations. Usually, if one has palpitations due to atrial fibrillation, it does feel irregular. Medications can often be prescribed to help control the heart rate and/or rhythm. In addition to causing symptoms such as palpitations, chest pain, shortness of breath or dizziness, clots can form in the atria due to blood stagnating and this increases the risk of stroke. This is why many of these patients need to take a blood thinner (warfarin or Coumadin).
Diagnosis of arrhythmias
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Written by and/or reviewed by Mark K. Urman, M.D. and Jeffrey F. Caren, M.D.