Sinus tachycardia

What is a sinus tachycardia?

The term tachycardia is used in medicine to describe a rapid heartbeat whereby the heart beats at a frequency of 100 beats per minute or more and then relaxes again. When this rhythm is generated by the sinus node, it is referred to as sinus tachycardia.

The heart normally functions in a specific rhythm. The regular contraction of the heart muscle is controlled by its own conduction system. In a healthy heart, this is managed by the so-called sinus node. This consists of specialized heart muscle cells located where the superior vena cava enters the right atrium.

Next, the electrical signal generated is transmitted to the two ventricles through the AV node and the bundle of His. The final stations of the conduction system are known as the Tawara bundle and Purkinje fibers. These then finally transmit the signal to the heart muscle cells of the two ventricles. They then contract and pump the blood into the systemic and pulmonary circulation.

The sinus node generates a frequency of around 60-80 beats per minute, which is the normal range for a healthy heart rate. In the event of sinus tachycardia, this rhythm center generates a significantly higher frequency of over 100 beats per minute.

What are causes for sinus tachycardia?

A distinction must be made between physiological and pathological causes for sinus tachycardia. Pathological sinus tachycardia can also be further divided into primary and secondary types.

In medicine a physiological process is one that is not considered pathological. An accelerated heartbeat can also occur briefly in response to a specific situation in which the heart's workload is increased without the presence of a disease. For example, this may occur during physical exercise or in psychologically stressful situations with emotional strain.

The heart rate naturally increases in situations where the body needs to handle greater demands. Pain can also be a cause of sinus tachycardia. The reason for this is the activation of the autonomic nervous system. This system cannot be voluntarily controlled and serves to adapt the body to external factors. During periods of increased stress, the sympathetic branch is particularly active.

When thinking about sinus tachycardia, it is important to consider the age of the individual. In adults, a heart rate over 100 beats per minute is classified as tachycardia. In contrast, a healthy heart rate is naturally much higher in infants and young children, and resting rates of 100–120 beats per minute are common and not typically a sign of illness.

However, sinus tachycardia can also have pathological causes. In primary sinus tachycardia, no clear trigger can be identified. A pathological alteration of the sinus node itself may be present.

Secondary sinus tachycardia, on the other hand, is linked to specific causes. These can be either within the heart or external to it. Heart conditions like heart failure, a heart attack, or a pulmonary embolism can lead to sinus tachycardia.

External factors other than the heart include fever, hyperthyroidism, oxygen deficiency, anemia, or a lack of fluid volume. Certain medications or stimulants like alcohol, nicotine, or caffeine can also trigger sinus tachycardia.

In these cases, the tachycardia occurs from an excessive activation of the sympathetic nervous system.

How dangerous is sinus tachycardia?

The risk that sinus tachycardia represents depends on the context and the extent of the increased frequency. Physiological and short-term sinus tachycardia is considered harmless.

To understand the potential health impact of tachycardia, it helps to take a quick look at how the heart works.

The heart's activity is divided into two main phases: systole and diastole. Systole includes the contraction and ejection phases, during which the heart pumps blood into the body and lungs.

Diastole follows and has two phases: relaxation and filling. During the filling phase, blood flows from the atria into the heart chambers. The smooth alternation of systole and diastole depends on several factors, including the proper functioning of the heart's electrical conduction system.

When the heart rate increases, it’s primarily the diastole (the filling phase) that shortens. However, diastole is just as important as systole for proper heart function. While the heart can compensate for a shorter relaxation and filling phase for a limited time, problems arise if it becomes too short.

This can have two main dangerous consequences. If the ventricles can no longer be sufficiently filled with blood, then not enough blood can be ejected, which ultimately leads to an undersupply of oxygen to the various organs.

Furthermore, it is important to note that the heart muscles themselves are also supplied with blood, particularly during diastole. Shortening this phase excessively leads to an undersupply in this area too. For this reason, any sinus tachycardia that cannot be linked to external factors and does not resolve on its own should be thoroughly evaluated and treated.

Symptoms: how does a rapid heartbeat present itself?

There are various symptoms that can manifest with sinus tachycardia. In most cases, there is increased sweating, a noticeable heartbeat or a headache.

When the heart rate is so high that adequate cardiac action is no longer possible, the reduced supply to the organs can also lead to short-term unconsciousness (syncope). If the heart muscle is seriously undersupplied with blood, there is also a risk of cardiogenic shock, in which the heart can no longer perform its function.

How is sinus tachycardia diagnosed?

In general, no further diagnosis is required if the tachycardia is temporary and occurs in a physiological context. However, if the accompanying symptoms are very severe, such as syncope, it is advisable to consult a doctor for clarification.

Sinus tachycardia is mostly diagnosed with an ECG. The electrocardiogram, or ECG for short, is used to map the electrical activity of the heart muscle cells. This can be used to determine the presence of sinus tachycardia and the corresponding rhythm. If necessary, this examination can also be carried out over a longer period as a long-term ECG or under exertion.

Other measures can be used to determine the cause of the tachycardia, depending on whether other abnormalities are found in the recording.

An echocardiogram is a commonly used imaging procedure in cardiology. It is an ultrasound examination of the heart. It can be performed via the chest wall from the outside as transthoracic echocardiography (TTE) or via the esophagus, which is located behind the heart, as transesophageal echocardiography (TEE).

Other more specialized diagnostic procedures may also be used depending on the suspected cause of the sinus tachycardia, and their use should always be considered on an individual basis.

How is sinus tachycardia treated?

Physiological sinus tachycardia does not require any specific treatment. In the treatment of pathological sinus tachycardia, it is always important to try to remove the triggering factors. This includes, for example, discontinuing certain medications or treating hyperthyroidism.

Symptomatic therapy can also be used in addition to causal therapy. A distinction must be made between acute and long-term therapy.

A severely increased heart rate must be treated acutely if it is severe enough. Initially, an attempt can be made to activate the parasympathetic nervous system as an antagonist of the sympathetic nervous system. To achieve this, it can be useful, as an example, to put cold water in the mouth or to exhale against closed airways to create increased pressure in the chest and abdomen. If these measures are not helpful, various medications can be used.

In long-term therapy, medication is also primarily used to reduce the frequency. These include beta blockers or antiarrhythmic drugs. The selection should always be made after weighing up the benefits and risks and taking individual patient factors into account.

What is the prognosis and chances of recovery from sinus tachycardia?

It is very hard to make a general statement about the prognosis of sinus tachycardia, since it can be triggered by many different factors. The chances of recovery therefore always depend on the underlying disease that caused it.

Which doctors & clinics specialize in the treatment of sinus tachycardia?

Specialists in internal medicine and cardiology specialize in the treatment of sinus tachycardia. Since the cause of sinus tachycardia can also be external to the heart, doctors from other specialties may also be involved in the diagnosis and treatment.

All the specialists listed here have been carefully reviewed and selected by us. They are all specialists in their field and have extensive experience in the treatment of sinus tachycardia. Benefit from their expertise and arrange your first personal consultation quickly and easily.