Arrhythmia is an irregular heartbeat. It may be too fast,
too slow, or out of rhythm. It occurs when the electrical signals that control
the heartbeat are delayed or blocked. This may occur because the specialized cells
that produce the signal are not working properly. It might also occur if the
signal does not travel through the heart normally. This could be the result of
scar tissue or an alteration in the structure of the heart. An arrhythmia can
also occur if some other part of the heart starts to produce electrical
functioning heart has clear pathways along which uninterrupted electrical
impulses travel from the sinus node to the ventricles. If there is a disruption
along the pathways or a problem with the tissues that create the impulses, the
heart may not beat correctly. This can cause an arrhythmia.
Conditions that may
block the pathways, interrupt electrical impulses, or otherwise cause a heart
not to function properly include:
blood pressure (hypertension)
overactive or underactive thyroid gland
of the heart muscle, for example from a heart attack
An arrhythmia can
develop if the heart’s physiology has been changed. The change may be caused by
reduced blood supply or damage to heart tissue. If the heart does not receive
an adequate supply of blood, its cells and tissues may be starved of oxygen and
unable to properly conduct electrical impulses. If a heart’s tissues have been
damaged or destroyed, the electrical impulses may not be able to travel
properly. Conditions that may change the heart’s structure include:
Coronary Artery Disease (CAD)
is a condition in which the arteries in the heart become narrow. This often
leads to a heart attack. In a heart attack, part of the heart muscle dies due
to lack of oxygen. This causes scarring, which can interfere with the movement
of electrical impulses through the heart. This may cause the heart to beat too
fast (tachycardia), too slow (bradycardia) or erratically (fibrillation).
Cardiomyopathy is disease of the heart muscle. This may cause expansion or
stretching of the walls of the ventricles. It may thicken and constrict the
wall of the left ventricle. This affects the way blood is pumped through the
heart and may damage heart tissue.
Valvular Heart Diseases
The heart valves can become narrow and/or leak. This may cause sections of the
heart muscle to stretch and thicken in some parts and thin in other ones.
cases, such as Wolff-Parkinson-White syndrome or Brugada syndrome, the cause of
an arrhythmia is a congenital heart defect or a genetic defect—meaning it is
present from birth. In other cases, a cause may not be found.
Many factors increase the risk of
arrhythmia. Some you can control; others you cannot. Eliminating as many of
these factors as you can through lifestyle and dietary changes will improve
your chances of living a long healthy life.
The risk of arrhythmia increases with age. This can
be due to many factors including structural heart disease, drug use, and heart
attack. In addition, there are normal changes that occur as the heart ages. These
may decrease the conductivity of electrical impulses.
Consuming large amounts of alcohol can affect the
electrical impulses in your heart in a variety of ways. Multiple studies
demonstrate that moderate to heavy alcohol consumption significantly increases
the risk of developing atrial fibrillation. Chronic alcohol abuse may lead to
cardiomyopathy that causes your heart to beat less effectively.
Nicotine or Caffeine
Caffeine, nicotine, and other stimulants accelerate
your heart rate. Long-term, frequent use of these stimulants—particularly
nicotine—may lead to more serious arrhythmias or heart diseases that can cause
A person with uncontrolled diabetes is at an
increased risk of developing coronary artery disease and high blood pressure.
Uncontrolled diabetes also increases the chances of heart attack compared to a
person whose diabetes is controlled.
Some over-the-counter and prescription
medicines—such as cough suppressants and cold medications—contain
pseudoephedrine. This may speed up your heart rate, increase blood pressure,
and enhance an arrhythmia. Some cardiac medications, including those used to
treat arrhythmia, can paradoxically cause an arrhythmia.
Some herbs have been associated with arrhythmias.
These include creatine, guarana, cola nut, and ephedra.
Electrolytes, such as potassium, sodium, calcium,
and magnesium, are essential for maintaining proper conduction of electricity
between cells. Electrolyte levels that are either too high or too low can
affect electrical impulses and may result in an arrhythmia.
Congenital heart defects—problems that are present
at birth—can affect the heart’s structure and its ability to function properly.
High Blood Pressure
High blood pressure (hypertension) increases your
risk of developing coronary artery disease or experiencing heart failure. It
may also cause the walls of your heart to become thicker, which can change how
electrical impulses circulate in your heart.
Amphetamines and cocaine profoundly affect the
heart, possibly causing any number of arrhythmias. They might also cause
ventricular fibrillation, which can lead to sudden death.
Endocarditis or pericarditis—which can be caused by
viral infections—can weaken the heart muscle and the sac around the heart. This
makes transmission of electrical impulses and contractions more difficult.
Obesity is a risk factor for coronary heart
disease, diabetes, cancer, cardiovascular disease, heart disease, and
Obstructive Sleep Apnea
People with obstructive sleep apnea often
experience bradycardia or atrial fibrillation. Sleep apnea can also deprive
your body of oxygen, which places even more stress on the heart.
Previous Heart Surgery
Heart surgery may damage heart muscle, making electrical
conduction and contraction more difficult.
An overactive or underactive thyroid increases your
chances of developing an arrhythmia. Whether it is releasing too many hormones
or not enough, your thyroid gland can affect your heartbeat, which may lead to
a too-fast or too-slow heart rate.