Heart rhythm disorders (arrhythmias)

Some people notice that they have an irregular heartbeat because they have a fluttering or pounding feeling in their chest (palpitations). If your heart beats very fast while you’re at rest, you might feel the high pulse as a racing heart. But if the heart only briefly “skips a beat,” a heart rhythm disorder may go unnoticed.

Other symptoms usually only develop if the heart beats so abnormally that it can no longer pump enough blood around the body: If your brain doesn’t get enough oxygen as a result, you may become dizzy or unconscious.

The heart muscle itself needs oxygen too. If it gets too little oxygen because of an abnormal heartbeat, you may have chest pain. Some people have difficulty breathing and feel weak too.

A heartbeat that is too slow (bradycardia) is usually caused by something known as AV block. Here the electrical signals that travel from the upper heart to the lower heart are passed on later than usual, or aren’t passed on at all for short amounts of time. Bradycardia may also occur if the heart’s natural pacemaker (the sinus node) fails to send some signals or can no longer send them properly.

People with atrial fibrillation often have a fast heartbeat (tachycardia) together with an irregular heart rate. Other causes of a fast heartbeat include atrial flutter and scar tissue in the heart.

Heart problems like atrial fibrillation, AV block and scarring are usually caused by heart diseases too, such as

• coronary artery disease and heart attack,
• heart valve diseases,
• inflammation of the heart muscle, and
• heart failure.

Because of this, factors that damage the heart (like high blood pressure, smoking, drug abuse and too much alcohol) can also increase the risk of abnormal heartbeats.

Some people are born with a heart rhythm disorder – for instance, due to defects affecting electrical pathways in the heart. Then additional pathways carry electrical signals from the upper heart to the lower heart, which may cause the heart to suddenly beat very fast. This can also happen if you inherit heart cells that don’t work properly.

Further possible causes of an abnormal heartbeat include certain other diseases, like an overactive thyroid, chronic kidney disease or diabetes. Electricity-related accidents and injuries can affect your heart rhythm too.

Sometimes, though, abnormal heartbeats develop in people with a healthy heart and without other medical conditions. Then the abnormal heartbeat is said to be “idiopathic.”

Abnormal heartbeats can occur as a side effect of certain medicines, including some heart medicines and blood-pressure-lowering medicines, as well as some antidepressants and cancer medicines.

Heart rhythm disorders are common – especially in older people and those who already have another heart condition. In those cases, the abnormal heartbeat usually has to be treated. In younger people who are otherwise healthy, an abnormal heartbeat is often less of a problem. Genetically inherited heart rhythm disorders are different, though. They can sometimes be life-threatening.

Abnormal heartbeats can start suddenly and then go away again after a few seconds or minutes. Sometimes these episodes repeat regularly. In certain disorders, the heart rhythm is never normal.

Abnormal heartbeats sometimes lead to sudden fainting – with a risk of falls and injuries. They can also result in heart failure or make existing heart failure worse.

In atrial fibrillation, blood clots may form in the heart. If these clots break loose, they can travel through the bloodstream to the brain and cause a stroke.

The risk of life-threatening complications is greater if the heart is already damaged – for instance, because of a heart attack. Then abnormal heartbeats can cause circulatory failure, cardiac arrest or ventricular fibrillation (V-fib). In V-fib, the heart rate is so fast that the individual beats aren't strong enough to pump blood around the body. Without resuscitation, people can die as a result (sudden cardiac death).

An abnormal heartbeat may be felt as a racing, fluttering or pounding sensation in the chest. Sometimes, a doctor notices that the heartbeat is too slow, too fast, or irregular when measuring someone's pulse or listening to their heart with a stethoscope.

An electrocardiogram (ECG) can be used to find out exactly what type of abnormal heartbeat it is. If there's reason to believe you have a heart rhythm disorder, but the ECG readings are normal, that might be because your heartbeat only becomes abnormal every now and then, or only under physical strain. For this reason, a continuous ECG recording or stress test ECG is often done to be sure.

Other examinations may help to find out the causes or effects of the abnormal heartbeat. For example, an ultrasound scan of the heart (echocardiogram) can detect heart failure.

The treatment options for an abnormal heartbeat will depend on the answers to the following questions:

• What kind of abnormal heartbeat is it?
• What is causing it, and can the cause be treated?
• How severe is it?
• Is it causing symptoms?
• Is there a higher risk of complications such as stroke or life-threatening ventricular fibrillation?

Because of this, different people may have very different treatments: Some don’t need any treatment. Those with a type of rapid heartbeat called PSVT can sometimes make it go away themselves using a special breathing technique. Others take medicine to stabilize their heart rhythm. Some need treatment with brief, controlled electric shocks to restore a normal rhythm (cardioversion). Certain surgical procedures can help too. One example is catheter ablation, which aims to destroy (ablate) the heart tissue that is causing the abnormal heartbeat.

If the heart needs support on a more permanent basis, special electrical devices may be considered: People whose heartbeat is too slow – for instance, due to AV block or because the sinus node isn't working properly – may need a pacemaker. Abnormal heartbeats that could lead to life-threatening ventricular fibrillation can be treated with a device called a defibrillator.

Sometimes there are a number of treatment options that have different pros and cons. Then you can use our decision aid to help choose a treatment that is suitable for you, together with your doctor.

Symptoms like fatigue and difficulty breathing can mean that you’re less fit in daily life or need help with everyday activities. But treating an abnormal heartbeat can be bothersome too – for instance, if you have to regularly take anticoagulants ("blood-thinning" medicines) because of atrial fibrillation. People who permanently have a pacemaker (e.g. because of AV block) – and those who have had a defibrillator implanted due to ventricular tachycardia – also have limitations in everyday life.

When people are ill or need medical advice, they usually go to see their family doctor first. You can read about how to find the right doctor in our topic "Health care in Germany" – and our list of questions can help you to prepare for your appointment.