The Neocrown vaccine does not cause atrial flutter. There are three types of new crown vaccines: adenovirus vector vaccine, inactivated vaccine, and recombinant protein vaccine. It can help prevent new crowns effectively and generally does not cause arrhythmias such as atrial flutter. The most common adverse reactions to the new crown vaccine are localized pain, itching, redness, swelling, and fever. Hard nodules and lumps may appear, which usually disappear on their own 2~3 days after injection. In severe cases, rashes such as anaphylactic purpura may occur, requiring medical treatment as soon as possible. Atrial flutter is an arrhythmia with a fast impulse frequency. The electrocardiogram shows the disappearance of p-waves and the appearance of F-waves with basically the same size, shape and spacing. It is usually associated with a primary disease such as hypertension and requires treatment of the primary disease. Controls ventricular rate, but is not associated with neocoronary vaccination. People who are experiencing fever, allergies, pregnancy, or acute illness should not be vaccinated with the new crown vaccine. Also, if atrial flutter occurs you need to seek medical attention as soon as possible to avoid delays.