The rate and rhythm of the heart is normally controlled by the sinoatrial node. This tissue produces rhythmic electrical pulses that control the beating of the heart. It is influenced by chemicals in the blood and by nerves, such as the vagus nerve. The electrical impulses are carried through fibers to the lower chambers of the heart, or ventricles. This conduction system allows for the coordinated contraction of the various chambers of the heart. Any dysfunction of the sinoatrial node or the conducting system can lead to irregular heart beats. The abnormal heart beats can be irregular, rapid or slow. All these abnormalities may prevent the heart from effectively pumping blood. This compromised function of the heart can lead to a variety of symptoms. Abnormal heart beats are more common in people over 65 years of age.
Causes of Heart Rhythm Irregularity
There are many causes of heart rate and rhythm irregularities. They include heart diseases, rheumatic fever, congenital heart disease, cardiomyopathy, previous heart attack, heart-muscle inflammation. endocrine disorders, thyroid and adrenal-gland diseases. Fluid and electrolyte imbalances, particularly those that alter the levels of potassium in the body, may produce arrhythmias. Side effects of certain drugs, such as digitalis, beta-adrenergic blockers, stimulants and diuretics can lead to abnormal heart rate and rhythm. Overdose of certain drugs, such as antidepressants, marijuana and cocaine can also produce arrhythmias. There are often abnormalities of heart rate and rhythm following chest or heart surgery.
Signs and Symptoms of Heart Rhythm Irregularity
You may not notice some irregularities of the heart beat. On the other hand, you may feel and extra or a skipped beat, or the pulse may seem rapid or slow. Episodes of lightheadedness or fainting may occur, if the heart beat irregularity prevents enough blood from being pumped to the brain. Shortness of breath and chest pain or chest discomfort may occur. Loss of consciousness may develop.
Find more information
Medical Content Last Updated on 07/12/2008
The information contained on this site is for the sole purpose of
being informative. This information is not and should not be used or relied upon as medical
advice. Always seek the advice of your physician, nurse
Or other qualified health care provider before you undergo any treatment or
for answers to any questions you may have regarding a medical condition.
If you believe you have a medical emergency, please discontinue use
of MyElectronicMD and call 911 now.
Nothing contained on or provided through the service is intended to be or is
to be used for medical diagnosis or treatment.
Your use of this site is subject to certain terms and conditions.