Dr. MJ Bazos MD,
What Is an Arrhythmia?
An arrhythmia is a change in the
regular beat of the heart. The heart may seem to skip a beat or beat irregularly
or very fast or very slowly.
Having an Arrhythmia Mean That a Person Has Heart Disease?
No, not necessarily. Many arrhythmias
occur in people who do not have underlying heart disease.
What Causes Arrhythmias?
Many times, there is no recognizable
cause of an arrhythmia. Heart disease may cause arrhythmias. Other causes
include: stress, caffeine, tobacco, alcohol, diet pills, and cough and cold
Are Arrhythmias Serious?
The vast majority of people with
arrhythmias have nothing to fear. They do not need extensive exams or special
treatments for their condition.
people, arrhythmias are associated with heart disease. In these cases, heart
disease, not the arrhythmia, poses the greatest risk to the patient.
In a very small number of people with
serious symptoms, arrhythmias themselves are dangerous. These arrhythmias
require medical treatment to keep the heartbeat regular. For example, a few
people have a very slow heartbeat (bradycardia), causing them to feel
lightheaded or faint. If left untreated, the heart may stop beating and these
people could die.
How Common Are
commonly in middle-age adults. As people get older, they are more likely to
experience an arrhythmia.
the Symptoms of an Arrhythmia?
people have felt their heart beat very fast, experienced a fluttering in their
chest, or noticed that their heart skipped a beat. Almost everyone has also felt
dizzy, faint, or out of breath or had chest pains at one time or another. One of
the most common arrhythmias is sinus arrhythmia, the change in heart rate that
can occur normally when we take a breath. These experiences may cause anxiety,
but for the majority of people, they are completely harmless.
You should not panic if you experience
a few flutters or your heart races occasionally. But if you have questions about
your heart rhythm or symptoms, check with your doctor.
Originating in the
Sinus Arrhythmia. Cyclic
changes in the heart rate during breathing. Common in children and often found
Sinus Tachycardia. The
sinus node sends out electrical signals faster than usual, speeding up the heart
Sick Sinus Syndrome. The
sinus node does not fire its signals properly, so that the heart rate slows
down. Sometimes the rate changes back and forth between a slow (bradycardia) and
fast (tachycardia) rate.
Supraventricular Contractions or Premature Atrial Contractions (PAC). A beat
occurs early in the atria, causing the heart to beat before the next regular
(SVT), Paroxysmal Atrial Tachycardia (PAT). A series of early beats in the
atria speed up the heart rate (the number of times a heart beats per minute). In
paroxysmal tachycardia, repeated periods of very fast heartbeats begin and end
Atrial Flutter. Rapidly
fired signals cause the muscles in the atria to contract quickly, leading to a
very fast, steady heartbeat.
Fibrillation. Electrical signals in the atria are fired in a very fast and
uncontrolled manner. Electrical signals arrive in the ventricles in a completely
irregular fashion, so the heartbeat is completely irregular.
Abnormal pathways between the atria and ventricles cause the electrical
signal to arrive at the ventricles too soon and to be transmitted back into the
atria. Very fast heart rates may develop as the electrical signal ricochets
between the atria and ventricles.
Originating in the
Complexes (PVC). An electrical signal from the ventricles causes an early
heart beat that generally goes unnoticed. The heart then seems to pause until
the next beat of the ventricle occurs in a regular fashion.
Ventricular Tachycardia. The heart
beats fast due to electrical signals arising from the ventricles (rather than
from the atria).
Fibrillation. Electrical signals in the ventricles are fired in a very fast
and uncontrolled manner, causing the heart to quiver rather than beat and pump
What Happens in the Heart
During an Arrhythmia?
the heart beats normally helps to explain what happens during an arrhythmia.
The heart is a muscular pump divided into
four chambers—two atria located on the top and two ventricles located on
Normally each heartbeat starts
in the right atrium. Here, a specialized group of cells called the sinus node,
or natural pacemaker, sends an electrical signal. The signal spreads throughout
the atria to the area between the atria called the atrioventricular (AV) node.
The AV node connects to a group of special
pathways that conduct the signal to the ventricles below. As the signal travels
through the heart, the heart contracts. First the atria contract, pumping blood
into the ventricles. A fraction of a second later, the ventricles contract,
sending blood throughout the body.
the whole heart contracts between 60 and 100 times per minute. Each contraction
equals one heartbeat.
An arrhythmia may
occur for one of several reasons:
•Instead of beginning in the sinus node,
the heartbeat begins in another part of the heart.
•The sinus node develops an abnormal rate
•A patient has a heart block.
What Is a Heart Block?
Heart block is a condition in which
the electrical signal cannot travel normally down the special pathways to the
ventricles. For example, the signal from the atria to the ventricle may be (1)
delayed, but each one conducted; (2) delayed with only some getting through; or
(3) completely interrupted. If there is no conduction, the beat generally
originates from the ventricles and is very slow.
What Are the Different Types of
There are many types of
arrhythmias. Arrhythmias are identified by where they occur in the heart (atria
or ventricles) and by what happens to the heart's rhythm when they occur.
Arrhythmias arising in the atria are
called atrial or supraventricular (above the ventricles) arrhythmias.
Ventricular arrhythmias begin in the ventricles. In general, ventricular
arrhythmias caused by heart disease are the most serious.
How Does the Doctor Know That I
arrhythmia can be detected by listening to the heart with a stethoscope.
However, the electrocardiogram is the most precise method for diagnosing the
An arrhythmia may not occur at
the time of the exam even though symptoms are present at other times. In such
cases, tests will be done if necessary to find out whether an arrhythmia is
causing the symptoms.
Can Be Done?
First the doctor will
take a medical history and do a thorough physical exam. Then one or more tests
may be used to check for an arrhythmia and to decide whether it is caused by
Tests for Detecting
Electrocardiogram (ECG or
EKG). A record of the electrical activity of the heart. Disks are placed on the
chest and connected by wires to a recording machine. The heart's electrical
signals cause a pen to draw lines across a strip of graph paper in the ECG
machine. The doctor studies the shapes of these lines to check for any changes
in the normal rhythm. The types of ECGs are:
Resting ECG. The patient lies
down for a few minutes while a record is made. In this type of ECG, disks are
attached to the patient's arms and legs as well as to the chest.
Exercise ECG (Stress Test). The
patient exercises either on a treadmill machine or bicycle while connected to
the ECG machine. This test tells whether exercise causes arrhythmias or makes
them worse or whether there is evidence of inadequate blood flow to the heart
(Holter) Monitoring. The patient goes about his or her usual daily
activities while wearing a small, portable tape recorder that connects to the
disks on the patient's chest. Over time, this test shows changes in rhythm (or
"ischemia") that may not be detected during a resting or exercise ECG.
Transtelephonic Monitoring. The
patient wears the tape recorder and disks over a period of a few days to several
weeks. When the patient feels an arrhythmia, he or she telephones a monitoring
station where the record is made. If access to a telephone is not possible, the
patient has the option of activating the monitor's memory function. Later, when
a telephone is accessible, the patient can transmit the recorded information
from the memory to the monitoring station. Transtelephonic monitoring can reveal
arrhythmias that occur only once every few days or weeks.
Electrophysiologic Study (EPS). A
test for arrhythmias that involves cardiac catheterization. Very thin, flexible
tubes (catheters) are placed in a vein of an arm or leg and advanced to the
right atrium and ventricle. This procedure allows doctors to find the site and
type of arrhythmia and how it responds to treatment.
How Are Arrhythmias Treated?
Many arrhythmias require no treatment
whatsoever. Serious arrhythmias are treated in several ways depending on what is
causing the arrhythmia. Sometimes the heart disease is treated to control the
arrhythmia. Or, the arrhythmia itself may be treated using one or more of the
There are several kinds of drugs used to treat arrhythmias. One or more drugs
may be used.
Drugs are carefully chosen
because they can cause side effects. In some cases, they can cause arrhythmias
or make arrhythmias worse. For this reason, the benefits of the drug are
carefully weighed against any risks associated with taking it. It is important
not to change the dose or type of your medication unless you check with your
If you are taking drugs for
an arrhythmia, one of the following tests will probably be used to see whether
treatment is working: a 24-hour electrocardiogram (ECG) while you are on drug
therapy, an exercise ECG, or a special technique to see how easily the
arrhythmia can be caused. Blood levels of antiarrhythmic drugs may also be
quickly restore a heart to its normal rhythm, the doctor may apply an electrical
shock to the chest wall. Called cardioversion, this treatment is most often used
in emergency situations. After cardioversion, drugs are usually prescribed to
prevent the arrhythmia from recurring.
Defibrillators. These devices are used to correct serious ventricular
arrhythmias that can lead to sudden death. The defibrillator is surgically
placed inside the patient's chest. There, it monitors the heart's rhythm and
quickly identifies serious arrhythmias. With an electrical shock, it immediately
disrupts a deadly arrhythmia.
Artificial Pacemaker. An
artificial pacemaker can take charge of sending electrical signals to make the
heart beat if the heart's natural pacemaker is not working properly or its
electrical pathway is blocked. During a simple operation, this electrical device
is placed under the skin. A lead extends from the device to the right side of
the heart, where it is permanently anchored.
Surgery. When an arrhythmia
cannot be controlled by other treatments, doctors may perform surgery. After
locating the heart tissue that is causing the arrhythmia, the tissue is altered
or removed so that it will not produce the arrhythmia.
How Can Arrhythmias Be Prevented?
If heart disease is not causing the
arrhythmia, the doctor may suggest that you avoid what is causing it. For
example, if caffeine or alcohol is the cause, the doctor may ask you not to
drink coffee, tea, colas, or alcoholic beverages.
Is Research on Arrhythmias Being
The National Heart, Lung, and
Blood Institute (NHLBI) supports basic research on normal and abnormal
electrical activity in the heart to understand how arrhythmias develop. Clinical
studies with patients aim to improve the diagnosis and management of different
arrhythmias. These studies will someday lead to better diagnostic and treatment