Heart rhythm problems, called arrhythmias, can cause a few types of symptoms. These symptoms happen because the heart isn't beating regularly or may not be pumping blood as well as normal.
Some of these symptoms include palpitations, lightheadedness, fainting, and shortness of breath.
Having palpitations means that you are unusually aware of your
heartbeat. The experience of palpitations is often described differently by
different people. Some people report a vague "fluttering" in their chests or the
feeling of a "skipped beat." Others note a "pounding sensation" or feel
that the heart is "jumping out of my chest." Palpitations are rarely
What are the different types of palpitations?
The pattern of the palpitations can be very helpful in determining
the type of arrhythmia that caused them. If you see a doctor about your
palpitations, it is very helpful if you can demonstrate the rhythm and speed of
the palpitations by tapping your fingers on a desk or table. This can help your
doctor figure out whether the palpitations were the result of an arrhythmia and
in some cases may allow a relatively accurate diagnosis as to the specific
arrhythmia that caused the palpitations.
Your doctor will likely not diagnose an arrhythmia based on
your demonstration. But it can be a very helpful start if you are not experiencing
arrhythmia while you are in your doctor's office (which means your doctor will
be unable to record the arrhythmia on an EKG during the visit).
How do palpitations cause chest discomfort?
Some people experience rapid heart rates not as palpitations but
rather as chest pain. In people who have healthy hearts, palpitations may cause a
pounding or thumping sensation that can be painful or uncomfortable, rather
than the heavy, tight, or squeezing sensation, called angina, usually
associated with heart attacks. In people who have coronary artery disease, a rapid
heart rate can cause angina. How you describe your pain may help your doctor
figure out whether the chest pain is the result of an abnormal rhythm or angina.
In many cases, your doctor may not be sure based strictly on your description. So he or she will probably order an electrocardiogram (EKG, ECG) or further stress
testing to evaluate the rhythm or rule out angina.
If you have an arrhythmia that causes your heart to beat too fast or
too slow, you may feel lightheaded or dizzy. This happens because your heart
cannot pump blood effectively during excessively fast or slow heart rates. The
ineffective pumping action decreases your blood pressure, reducing the amount
of blood that reaches your brain.
The sensation of lightheadedness is a result of this lack of blood
flow to the brain. If your blood pressure drops too low, you may feel that you
are about to pass out. This sensation is called presyncope. Syncope is the
medical term for a temporary loss of consciousness (passing out).
When is lightheadedness not caused by an arrhythmia?
Dizziness can be caused by conditions other than arrhythmia. For
this reason, your doctor will try to find out whether your
dizziness is caused by a heart condition, medicine, or other things.
Other causes of lightheadedness include hyperventilation, panic or anxiety attacks, prolonged standing, and excessive fluid loss caused by problems such as vomiting or diarrhea.
Many of the medicines used to treat heart conditions, such as
beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE)
inhibitors, and diuretics, can lower the blood pressure excessively and result
in lightheadedness. In general, medicine-induced lightheadedness frequently
occurs soon after you stand up because of a drop in blood pressure that happens
when you stand (orthostatic hypotension). In contrast, lightheadedness due to
an arrhythmia can occur even when you are sitting or reclining.
Syncope (say "SING-kuh-pee") refers to a sudden loss of
consciousness that doesn't last long. Syncope may be the first sign that you
have an arrhythmia. And it is a very worrisome symptom for several
Fainting can result in a serious injury (for
example, if you faint while climbing stairs or driving).
because your brain did not get enough oxygen to function, which may be a
warning sign that you have a serious medical condition.
An arrhythmia can cause syncope in the same way that it causes
lightheadedness (presyncope). Your heart cannot pump blood effectively during
excessively fast or slow heart rates, reducing the amount of blood that reaches
your brain. With syncope, though, the arrhythmia causes such a dramatic drop
in the blood pressure that the brain doesn't receive enough blood to keep you
awake. So you lose consciousness. For an arrhythmia to
cause syncope, your heart rate must be extremely fast or extremely slow, or you
must also have some other heart condition.
How long does syncope last?
It is important to recognize that syncope is transient, meaning
that you wake up soon after fainting. Consciousness may return because the
arrhythmia spontaneously stops and a normal heart rhythm and blood pressure
return. Even if the arrhythmia persists, you may still regain consciousness.
When you have an episode of syncope due to an arrhythmia, it typically happens
while you are standing or sitting, and the loss of consciousness causes you to
fall to the floor. After you are lying down, blood flow returns to your brain,
even though your blood pressure may remain low. When adequate blood flow
returns to your brain, you will likely wake up.
What are the risks associated with passing out from an arrhythmia?
Fast or slow arrhythmias may cause you to pass out.
Depending on your position and activity at the time of the episode, you may
seriously injure yourself. If you are standing up at the time of the
arrhythmia, you may pass out and fall. The fall may cause you to injure your head,
break an arm or leg, or receive other injuries. If you are driving, you may
crash, causing severe injury to yourself and anyone else involved.
Passing out may be a sign that you are at risk for a life-threatening
arrhythmia. If you have symptoms of an arrhythmia that may cause you to pass
out, do not drive any vehicle until your condition has been evaluated and
Shortness of breath
A feeling of shortness of breath, which doctors call dyspnea,
frequently happens during arrhythmias. This symptom can be very difficult for
people to describe and may be referred to as:
Shortness of breath.
Tightness in the
Feeling tired from walking.
What causes shortness of breath?
When an arrhythmia causes the heart to beat too fast, the heart
doesn't pump effectively. Specifically, there may not be enough time between
heartbeats for the heart to fill with blood, causing blood to back up into the
lungs. The increased pressure and fluid in the lungs results in the feeling of
shortness of breath.
Olgin JE, Zipes DP (2012). Specific arrhythmias: Diagnosis and treatment. In RO Bonow et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed., vol. 1, pp. 771–824. Philadelphia: Saunders.
Primary Medical Reviewer
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical Reviewer
John M. Miller, MD, FACC - Cardiology, Electrophysiology
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