Arrhythmia: Causes, symptoms, types, and treatment
Arrhythmias occur when the electrical signals to the heart that coordinate heartbeats are not working properly. For instance, some people experience irregular heartbeats, which may feel like a racing heart or fluttering.
Many heart arrhythmias are harmless; however, if they are particularly abnormal, or result from a weak or damaged heart, arrhythmias can cause serious and even potentially fatal symptoms.
What is arrhythmia?
Arrhythmia, or abnormal heart rate, has a variety of causes.
Heart arrhythmia, also known as irregular heartbeat or cardiac dysrhythmia, is a group of conditions where the heartbeat is irregular, too slow, or too fast.
Arrhythmias are broken down into:
- Slow heartbeat: bradycardia.
- Fast heartbeat: tachycardia.
- Irregular heartbeat: flutter or fibrillation.
- Early heartbeat: premature contraction.
Most arrhythmias are not serious, but some can predispose the individual to stroke or cardiac arrest.
Causes of arrhythmia?
Any interruption to the electrical impulses that cause the heart to contract can result in arrhythmia.
For a person with a healthy heart, they should have a heart rate of between 60-100 beats per minute when resting.
The more fit a person is, the lower their resting heart rate.
Olympic athletes, for example, will usually have a resting heart rate of under 60 beats per minute because their hearts are very efficient.
A number of factors can cause the heart to work incorrectly, they include:
- alcohol abuse
- drug abuse
- excessive coffee consumption
- heart disease like congestive heart failure
- hypertension (high blood pressure)
- hyperthyroidism (an overactive thyroid gland)
- mental stress
- scarring of the heart, often the result of a heart attack
- some dietary supplements
- some herbal treatments
- some medications
- structural changes of the heart
A healthy person will hardly ever suffer from long-term arrhythmia unless they have an external trigger, such as drug abuse or an electric shock. If there is an underlying problem, however, the electrical impulses may not be able to travel through the heart correctly, increasing the likelihood of arrhythmia.
Symptoms of arrhythmia
Some patients have no symptoms, but a doctor might detect an arrhythmia during a routine examination or on an EKG.
Even if a patient notices symptoms, it does not necessarily mean there is a serious problem; for instance, some patients with life-threatening arrhythmias may have no symptoms while others with symptoms may not have a serious problem.
Symptoms depend on the type of arrhythmia; we will explain the most common below:
Symptoms of tachycardia
Tachycardia is when the heart beats quicker than normal; symptoms include:
- breathlessness (dyspnea)
- syncope (fainting, or nearly fainting)
- fluttering in the chest
- chest pain
- sudden weakness
Symptoms of bradycardia
Bradycardia is when the heart beats slower than normal; symptoms include:
- angina (chest pain)
- trouble concentrating
- difficulties when exercising
- fatigue (tiredness)
- shortness of breath
- syncope (fainting or nearly fainting)
- diaphoresis, or sweating
Symptoms of atrial fibrillation
Atrial fibrillation is when the upper chambers of the heart beat in an irregular pattern and out of synchrony with the lower chambers. Symptoms often develop rapidly, although sometimes, there are no symptoms:
- angina (chest pain)
- breathlessness (dyspnea)
- syncope (fainting, or nearly fainting)
Treatments for arrhythmia
Treatment for arrhythmia is only required if the condition is putting the patient at risk of a more serious arrhythmia or a complication, or if the symptoms are very severe.
Treatments for bradycardia
A doctor may recommend a pacemaker to treat bradycardia.
If bradycardia is caused by an underlying condition, that condition needs to be treated first. If no underlying problem is found, the doctor may advise implanting a pacemaker.
A pacemaker is a small device that is placed under the skin of the chest or abdomen to help control abnormal heart rhythms. Pacemakers use electrical pulses to prompt the heart to beat at a normal minimum rate.
Treatments for tachycardia
There are several different treatments for tachycardia:
Vagal maneuvers - certain movements that the patient can do themselves might stop some types of arrhythmia that start above the lower half of the heart.
Medications - these will not cure the patient, but are usually effective in reducing episodes of tachycardia and can help with proper electrical conduction of the heart.
Cardioversion - the doctor may use an electric shock or medication to reset the heart to its regular rhythm.
Ablation therapy - one or more catheters go through blood vessels into the inner heart. They are placed in areas of the heart that are thought to be the source of the arrhythmia and destroy small sections of those tissues.
ICD (implantable cardioverter-defibrillator) - the device is implanted near the left collarbone and monitors heart rhythm; if it detects an abnormally fast rhythm, it stimulates the heart to return to a normal rhythm.
Maze procedure - a series of surgical incisions are made in the heart. They then heal into scars and form blocks. These blocks guide the electrical impulses, helping the heart to beat efficiently.
Ventricular aneurysm surgery - sometimes, an aneurysm (bulge) in a blood vessel that leads to the heart causes an arrhythmia. If other treatments do not work, a surgeon may remove the aneurysm.
Coronary bypass surgery - arteries or veins from elsewhere in the patient's body are grafted to the coronary arteries to bypass any regions that have become narrow, and improve the blood supply to the heart muscle (myocardium).
Types of arrhythmia
There are several types of arrhythmia:
This is irregular beating of the atrial chambers - nearly always too fast. Atrial fibrillation is common and mainly affects older patients. Instead of producing a single, strong contraction, the chamber fibrillates (quivers). In some cases, the atrium can fibrillate at 350 beats per minute and, in extreme cases, up to 600.
While fibrillation consists of many random and different quivers in the atrium, atrial flutter is usually from one area in the atrium that is not conducting properly, so the abnormal heart conduction has a consistent pattern. Neither are ideal for pumping blood through the heart.
Some patients may experience both flutter and fibrillation.Atrial flutter can be a serious condition, and untreated usually leads to fibrillation. A patient with atrial flutter will typically experience 250-350 beats per minute.
Supraventricular tachycardia (SVT)
A regular, abnormally rapid heartbeat. The patient experiences a burst of accelerated heartbeats that can last from a few seconds to a few hours. Typically, a patient with SVT will have a heart rate of 160-200 beats per minute. Atrial fibrillation and flutter are classified under SVTs.
Abnormal electrical impulses that start in the ventricles and cause an abnormally fast heartbeat. This often happens if the heart has a scar from a previous heart attack. Usually, the ventricle will contract more than 200 times a minute.
An irregular heart rhythm consisting of very rapid, uncoordinated fluttering contractions of the ventricles.The ventricles do not pump blood properly, they simply quiver. Ventricular fibrillation is life threatening and usually associated with heart disease. It is often triggered by a heart attack.
Long QT syndrome
A heart rhythm disorder that sometimes causes rapid, uncoordinated heartbeats. This can result in fainting, which may be life-threatening. It can be caused by a genetic susceptibility or certain medications.
Arrhythmia versus dysrhythmia
The words arrhythmia and dysrhythmia are interchangable. In other words, they mean the same thing. However, arrhythmia tends to be used more frequently.
Diagnosis of arrhythmia
The doctor will try to find out what triggers the patient's arrhythmia. This will involve a detailed interview, which may include the patient's medical history, family history, diet, and lifestyle.
The following tests might be ordered:
- blood and urine tests
- EKG (electrocardiogram)
- Holtermonitor - a wearable device that records the heart for 1-2 days
- chest X-ray
- tilt-table test
- electrophysiologic testing (or EP studies)
- heart catheterization
Risk factors for arrhythmia
Older age is a risk factor for arrhythmia.
The following are possible risk factors for arrhythmia:
- old age
- inherited gene defects
- heart problems
- hypothyroidism or hyperthyroidism
- some prescription medications, and over-the-counter drugs
- uncontrolled diabetes
- obstructive sleep apnea
- electrolyte imbalances
- heavy and regular alcohol consumption
- too much caffeine
- illegal drugs
Complications of arrhythmia
Stroke - fibrillation (quivering) means that the heart is not pumping properly. This can cause blood to collect in pools and clots can form. If one of the clots dislodges it may travel to a brain artery, blocking it, and causing a stroke. Stroke can cause brain damage and can sometimes be fatal.
Heart failure - prolonged tachycardia or bradycardia can result in the heart not pumping enough blood to the body and its organs - this is heart failure. Treatment can usually help improve this.