Treatments for fast heart rates
06/03/2014 6:58 AM
08/08/2014 10:24 AM
Millions of people experience irregular heartbeats, called arrhythmias. Arrhythmias are caused by problems with the electrical system that regulates the steady heartbeat. Most of the time arrhythmias are harmless. However, some abnormal heart rhythms can be serious or even deadly.
Several medications can be used to treat abnormal heart rhythms.
An abnormally fast heart rhythm, or tachycardia, can prove dangerous if the racing interferes with the heart’s ability to pump the blood properly. Sudden rapid heartbeats originating in the ventricles are the most dangerous arrhythmias. Those include ventricular tachycardia, and ventricular fibrillation (VF). Because the fibrillating ventricular muscle cannot contract and pump blood to the rest of the body, VF is a cause of sudden cardiac death. Without immediate treatment with an electric shock to return to normal rhythm, a person becomes unconscious and can die within minutes.
Atrial fibrillation (Afib) is the most common sustained arrhythmia. It affects more than 2 million people in the United States. In Afib the heart is irregular, and can be rapid. With Afib the atria, which are the upper chambers of the heart, fibrillate or quiver. Doctors often prescribe blood thinners to patients with Afib, to reduce the higher risk of stroke. Sometimes it is necessary to perform a cardioversion, which is a controlled shock to the heart to restore normal rhythm.
An electrophysiology (EP) study with catheter ablation is another option for treating arrhythmias, especially in patients for whom medications do not work effectively. The EP study is performed in a hospital. A local anesthetic is used to numb areas in the groin, and thin flexible wires called catheters are advanced through the blood vessels into the heart to record its electrical signals. After the source of arrhythmia is confirmed, a burst of energy through the catheter heats and destroys small areas of tissue that cause the arrhythmia. Either radiofrequency energy (heat) or cryotherapy (freezing) is used for ablation.
Technically advanced mapping systems are available to help show the position of the catheters in the body without the need for x-ray. They significantly lower the exposure to radiation during the EP study and ablation.
For people at high risk for the deadliest forms of arrhythmias, a defibrillator, or ICD may be needed. ICDs are devices that deliver life-saving shocks if a dangerously fast rhythm happens. They are about the size of a small cell phone and are implanted below the collarbone in a pocket under the skin. They are connected to one or more wires, or leads that go through a vein into the heart. Recently, an ICD that does not require a wire inside a vein has become available.
Catheter ablation is sometimes done in patients who already have an ICD, in order to decrease the frequency of arrhythmias, and to decrease the number of ICD shocks.
As technology advances, the tools for the treatment of cardiac arrhythmias improve as well. That should hopefully translate into better results for the patients and the physicians who treat them.