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What
is an Arrhythmia? What is an Arrhythmia? An abnormal heart rhythm is a change in either the speed or the pattern of the heartbeat -- the heart may beat too slowly, too rapidly or irregularly. A heart which beats too fast or too slow can cause: · Lightheadedness or dizziness · Palpitations (skipping, fluttering or pounding in the chest) · Fatigue · Chest pressure or pain · Shortness of breath · Fainting spells Sometimes there are no symptoms at all. Left untreated, certain abnormal heart rhythms can cause death. On the other hand, some arrhythmias are common and not associated with any untoward conditions, so called benign arrhythmias. One of the goals of evaluation is to sort out the serious from the benign forms of heart beat disturbances. How Are Arrhythmias Diagnosed? If your doctor suspects that you may have an arrhythmia, he or she will order one or more of the following diagnostic tests to determine the source of your symptoms. Electrocardiogram The electrocardiogram (ECG) records the heart's electrical activity. Small patches called electrodes are placed on your chest, arms and legs, and are connected by wires to the ECG machine. Your heart's electrical impulses are translated into a wavy line on a strip of moving paper, enabling doctors to determine the pattern of electrical current flow in the heart, diagnose arrhythmias and heart damage. Holter Monitor The Holter monitor is a small, portable machine you wear that makes a 24-hour continuous recording of electrical impulses as you go through your normal daily activities. The machine detects arrhythmias which may not show up in an ECG. You will be asked to maintain a diary of your activities and symptoms while wearing the monitor. Exercise Stress Test The exercise stress (treadmill) test enables physicians to record your heart's electrical activity which may not occur at rest. Event Recorder The event recorder (transtelephonic monitoring) is a tape recorder and disk worn over a period of time. When you feel an arrhythmia, you telephone a monitoring station so a record of the episode can be made. The monitor also has a memory you can activate if a phone is unavailable. Tilt Table Test Tilt table testing is used to diagnose vasovagal syncope (fainting or black-out spells) by trying to reproduce the black-out episodes. You will be tilted upright to about 60 degrees on a special table for a period of time with continuous recording of your ECG and blood pressure. The Electrophysiology Study The EP study allows doctors to:
The
Normal Heart
The
Premature Heartbeat
Abnormal
Heart Rhythms AV Nodal Reentry Tachycardia WPW: Wolff-Parkinson-White syndrome Bypass tract tachycardia Atrial fibrillation More information on EPS and ablation Mechanisms of tachycardias
AV nodal reentrant tachycardia
Wolff-Parkinson-White syndrome: Courtesy of Michael Lesh, UCSF
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The
heart is muscular and hollow, constantly pumping blood to deliver
oxygen and nutrients to the body. It is comprised of four
compartments, or chambers- two on the right side and two on the left.
The upper chamber on each side, called the atrium (plural:
atria), receives and collects blood. The lower chambers- the
ventricles-pump blood. All four chambers work together to move
life-sustaining blood through the body.
