How dangerous can atrial flutter become?

Similar to atrial fibrillation, the irregular heartbeat can cause complications in atrial flutter. The most common and at the same time most dangerous complication is a thromboembolism. This is the formation of a blood clot within the atria, which can spread via the heart chambers into the arterial vessels of the body.

This is particularly common when the blood clot spreads into the arteries supplying the brain, causing the arteries to be displaced and a stroke to occur. In rare cases, the blood clot that forms can also lead to a kidney or spleen infarction. The CHA2DS2VASc score can be used to estimate the risk of thromboembolism.

This is normally calculated for patients with atrial fibrillation. In general, patients with atrial flutter show a slightly lower risk of thromboembolism than patients with atrial fibrillation. The following parameters are considered by the CHA2DS2VASc-Score and are each scored with one point: chronic heart failure, arterial hypertension, diabetes mellitus, vascular diseases (CHD, PAD), age between 65 and 74 years, female gender.

In addition, previous thromboembolism (or stroke) and an age over 75 years are also evaluated with two points. Depending on gender and score, blood-thinning therapy (anticoagulation) is required. Vitamin K antagonists (Marcumar®), direct oral anticoagulants (Dabigatran, Apixaban, Edoxaban, Rivaroxaban) or heparin can be used for this purpose.

The CHA2DS2VASc score is used to estimate the risk of stroke without blood-thinning therapy (anticoagulation). With a CHA2DS2VASc score of 1, the annual risk of stroke is approximately 1%. With a score of 4, the risk of suffering a stroke is already 4%.

With a score of at least 6 points, the risk is already above 10%. In addition to the risk of a thromboembolism, other complications can occur due to chronic atrial flutter. Due to the permanently reduced cardiac output as a result of the irregular heartbeat, the clinical picture of heart failure can develop.

This leads to a backlog of blood in the body’s circulation (with the development of edema and ascites, among other things) and in the lungs (risk of pulmonary edema). Patients with a previously restricted heart pump function are particularly affected. In addition, a long-term rapid and irregular heartbeat can lead to damage to the heart muscle tissue (tachycardiomyopathy). This tissue remodelling also promotes the development of heart failure.