Abnormal heart rhythms

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 13, 2015
StartSymptomsAbnormal heart rhythms

The human heart beats about 70 times a minute, year after year, over 100,000 beats a day. A healthy heartbeat is usually regular, but sometimes the beat can become irregular. Irregular heartbeats or abnormal heart rhythms may be nothing major or serious and life-threatening.


Definition & Facts

The heart is an electrical system. Impulses generated by an area of heart tissue called the sinus node stimulate the contractions of the heart chambers, or atria and ventricles. An abnormal heartbeat, also known as an arrhythmia or dysrhythmia, can be too fast or too slow and can be either regular or irregular. If the arrhythmia affects the upper, smaller chambers of the heart it is called an atrial arrhythmia. If it affects the larger bottom chambers, it is a ventricular arrhythmia.


Heart disease is one of the most common causes of an arrhythmia, particularly if it affects the sinus node. However, other parts of the heart's electrical system can be affected. The sinus impulse might be blocked (heart block) or diverted into the wrong part of the heart muscle (Wolff–Parkinson–White syndrome, or WPW).

High blood pressure can cause arrhythmias, as can problems with the heart muscle or valves. Changes in the level of electrolytes - minerals like sodium and potassium that are dissolved in the blood - can make the heart beat more slowly or more quickly. Some medications have side effects that can affect the heart rate or electrical activity.

Simple anxiety or stress can make the heartbeat faster, and excessive caffeine can cause an increased pulse rate and skipped beats. Occasionally the heart will beat very quickly for a few seconds for no obvious reason. These palpitations can be completely harmless or a sign of a problem.

When to see a doctor

Any time an individual experiences an abnormal heart rhythm, a physician should be consulted to determine the cause. In many cases, it's very difficult to tell if a problem is serious. Occasional skipped beats from high caffeine intake are often a minor issue; decreasing or eliminating caffeine usually solves the problem.

Sinus tachycardia occurs when the heart beats more quickly than normal, although the rhythm is regular. When an adult's heart rate is greater than 100 beats per minute but the electrical activity is otherwise normal, it is likely to be sinus tachycardia. Although not dangerous in and of itself or for a short period, long-term sinus tachycardia may be an early sign of heart disease and should be evaluated promptly.

Ventricular fibrillation occurs when the electrical signals of the heart are completely disrupted and instead of beating properly, the large chambers (ventricles) just quiver. Circulation quickly stops in ventricular fibrillation, and if treatment is not immediate, the patient will quickly die. An arrhythmia that occurs in the presence of chest or arm pain, sweating, nausea and vomiting or unconsciouness may be life-threatening and requires immediate emergency medical attention.

Treatment & Therapy

The first step in treating an arrhythmia is to determine the cause. The doctor will take a health history and conduct a physical examination, paying particular attention to the sound and rhythm of the heartbeats. An electrocardiogram or EKG will be ordered to obtain a visual representation of the heart's electrical activity.

An echocardiogram is an imaging study that can show the interior of the heart as it beats. Echocardiograms are often used to evaluate the condition of the heart valves. Stress tests use exercise and/or medications to evaluate how the heart responds to increased demand. Blood tests such as lipid or electrolyte panels, or drug levels, indicate metabolic abnormalities or potential medication side effects.

Treatments for arrhythmia varies depending on the cause or the problem. If the sinus node is not sending signals properly, causing the heartbeat to be too slow (often called “sick sinus syndrome”), a pacemaker may be the treatment of choice. The pacemaker takes over the job of generating the electrical signals that tell the heart chambers to beat. Medications can speed or slow the pulse or correct irregular rhythms. If the arrhythmia is due to heart disease from a blocked artery, surgery may be necessary. In most cases, treatment will include stress reduction, dietary changes or exercise.

Prevention & Prophylaxis

Heart arrhythmias may or may not be preventable. For example, excessive caffeine use often causes heart irritability and may increase the pulse rate significantly or cause irregular beats. This problem is easily prevented by decreasing or avoiding caffeine in all forms.

Sick sinus syndrome, however, may result from increasing age or damage to the heart muscle that causes scarring. Rheumatic fever can cause scarring that results in sick sinus syndrome or other heart problems. These conditions are not necessarily preventable, although prompt antibiotic treatment of strep throat infection, which can result in rheumatic fever, may prevent heart muscle damage.

Preventing heart disease and related conditions like high blood pressure is one of the best ways to prevent abnormal heart rhythms. Obesity puts a strain on the heart and increases the risk of high blood pressure; maintaining a healthy weight is one of the most important steps in preventing heart disease. Smoking or any form of nicotine use, including electronic cigarettes or chewing tobacco, constricts blood vessels throughout the body.

Tobacco use increases the risk of both heart disease and high blood pressure as well as lung cancer. Illegal drugs like cocaine and amphetamine increase the risk of heart attack and stroke and should be avoided. A healthy diet helps protect the body from many medical problems that may result in heart problems. Regular exercise is another way to keep the heart healthy throughout the lifespan.

A healthy heart is the result of conscious efforts over many years. Despite all an individual can do, however, abnormal heart rhythms may still occur. Regular preventive medical care and prompt attention to problems can decrease the risk of serious complications or death from arrhythmia.

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