Heart rhythm disorders are pathological changes in the heartbeat pattern. They involve a disturbance in the generation or propagation of electrical impulses in the heart. Heart rhythm disorders are also referred to as arrhythmias.
In cases of arrhythmia, the heart rate may be
- too slow (fewer than 60 beats per minute, bradycardia),
- too fast (over 100 beats per minute, tachycardia), or
- irregular, meaning with extra beats
.
Disorders of electrical impulse generation are also collectively referred to as sick sinus syndrome.
Cardiac arrhythmias can originate in various parts of the heart:
- the atria,
- ventricles,
- AV node,
- the sinus node, or
- the cardiac conduction system.
Heart rhythm disorders can originate in various parts of the heart © designua | AdobeStock
These arrhythmias are then named according to where they occur, such as
- atrial flutter and atrial fibrillation,
- ventricular flutter and ventricular fibrillation, or
- AV blocks and sinus node disorders.
Some forms of cardiac arrhythmias can be dangerous, such as
- ventricular fibrillation and
- ventricular tachycardia.
However, other forms are relatively harmless.
If the conduction of electrical impulses within the heart is blocked, the following conditions may be diagnosed:
- Sinoatrial block: The conduction between the sinus node and the atria is disrupted.
- Atrioventricular block (AV block): The conduction between the atria and the ventricles is disrupted.
- Right bundle branch block or left bundle branch block: Conduction in the right or left bundle branch of the ventricular conduction system (Tawara bundle) is disrupted.
Distinguishing between the various arrhythmias—such as flutter and fibrillation—can be somewhat confusing. Therefore, the following is a brief overview of some important arrhythmias.
Sinus tachycardia: An abnormally fast heart rate originating from the sinus node. The causes can be varied; they are often unrelated to the heart itself, such as stress or thyroid disorders.
Sinus bradycardia: A heart rate that is too slow, originating from the sinus node. Sinus bradycardia is normal in well-trained athletes (“athlete’s heart”) or during sleep. However, it can also be caused by various underlying conditions, such as
Atrial flutter: The atrium is stimulated up to 300 times per minute. However, not all of these impulses are transmitted to the ventricles, so the ventricles typically beat more slowly. This condition is perceived as a racing heart.
Atrial flutter: The atrium is stimulated more than 300 times per minute. The ventricles then beat up to 180 times per minute (up to 200 times in children), which is perceived as unpleasant.
Atrial fibrillation is one of the most common heart rhythm disorders in Germany. Although it relatively rarely leads to a medical emergency, it is associated with an increased risk of, among other things,
Atrial ectopic tachycardia: In addition to the sinus node, there are other pacemaker sites in the atrium that can trigger electrical impulses. This results in a racing heartbeat.
AV nodal reentry tachycardia (AVNRT): Instead of a single conduction pathway, there are two pathways in the AV node that can “short-circuit.” This is also perceived as a racing heart. AVNRT is the most common congenital heart condition and primarily affects females.
Wolff-Parkinson-White syndrome (WPW syndrome): An additional bundle of conduction between the atria and ventricles causes circular electrical activity. This manifests as paroxysmal palpitations.
Ventricular tachycardia (VT): The cause of the increased heart rate lies in the ventricles. This is a life-threatening arrhythmia.
Ventricular flutter and ventricular fibrillation: The heart beats so fast that it can no longer pump enough blood to the body. This is a medical emergency! In ventricular flutter, the heart beats 200 to 350 times per minute; in ventricular fibrillation, it beats over 320 times per minute. The distinction between the two forms is fluid.
Causes and risk factors for cardiac arrhythmias can include
- congenital conditions,
- acquired conditions, or
- external factors
. Congenital conditions that can trigger cardiac arrhythmias include, among others,
Acquired conditions such as
can cause arrhythmia.
External causes include, for example,
- excessive alcohol and caffeine consumption,
- side effects of medications,
- anxiety, and
- infections.
Some patients have no symptoms. Others, however, perceive the altered heartbeat pattern as
- heart fluttering,
- heart fluttering,
- racing heart, or
- skipped heartbeats
.
Possible symptoms of a slow heartbeat include:
Possible symptoms of a rapid heartbeat include
- Pain in the heart and chest
- Chest tightness
- Shortness of breath
- Dizziness
- Dizziness
- Loss of consciousness
In the worst-case scenario, an arrhythmia can also lead to
.
The diagnosis is based on a physical examination. This involves the doctor measuring the pulse and listening to the heart.
In addition, an electrocardiogram (ECG) is performed. By recording the heart’s electrical activity on the ECG, an arrhythmia and its type can often be identified immediately.
For rare or irregular arrhythmias, a long-term ECG monitor is used. It records the heart rhythm over 24 hours or more. An event recorder can be used as an alternative or supplement to the long-term ECG. The patient activates it when they notice an irregular heartbeat.
If necessary, further tests are conducted to determine the cause of the arrhythmia.
An electrocardiogram can be used to distinguish between different types of arrhythmias © mattbadal | AdobeStock
Treatment depends on the type and cause of the arrhythmia, as well as the severity of the symptoms. If the arrhythmia has an organic cause, that cause must also be treated.
Medications used to treat cardiac arrhythmias are called antiarrhythmic drugs. These medications can influence the generation and conduction of electrical impulses—and thus the heart rate—in various ways.
A pacemaker is usually implanted when the heart rate is too slow. It uses electrical impulses to set the heart’s rhythm.
A defibrillator is implanted in cases of recurrent dangerous arrhythmias. It detects life-threatening disturbances and terminates them using electrical impulses.
Cardiac catheter ablation is used to ablate the affected areas of the heart (for example, in cases of atrial fibrillation). This interrupts the abnormal electrical conduction.
Through heart surgery (such as bypass surgery), doctors can correct the conditions that lead to reduced blood flow and, indirectly, to arrhythmia.
Specialists in heart rhythm disorders are cardiologists.
Depending on the cause of the arrhythmias, other specialists such as
be consulted.
1. What causes cardiac arrhythmias?
Cardiac arrhythmias are caused by disturbances in the generation or conduction of electrical impulses in the heart. These can be triggered, for example, by structural heart diseases, circulatory disorders, or metabolic changes.
2. What types of arrhythmias are there?
There are different types of arrhythmias, including a heart rate that is too fast (tachycardia), a heart rate that is too slow (bradycardia), or irregular heart rhythms such as atrial fibrillation.
3. When do cardiac arrhythmias occur?
In some people, cardiac arrhythmias occur only occasionally, such as during times of stress or physical exertion. In other cases, they may be persistent or associated with certain heart diseases.
4. When are heart rhythm disorders dangerous?
Particularly dangerous heart rhythm disorders can severely impair heart function and, in extreme cases, lead to loss of consciousness or sudden cardiac death, which is why early medical evaluation is important.
