Flutter atrium adalah jenis takiaritmia atrium yang paling sering dijumpai setelah atrial fibrilasi. Flutter atrium adalah bentuk takiaritmia berupa denyut atrium yang meningkat dan teratur, akibat aktivitas listrik atrium berlebihan ditandai dengan denyut atrial rerata 250 - 350 kali per menit. Risiko flutter atrium dikaitkan dengan berbagai kondisi medis tertentu dan hanya 2% kasus flutter atrium yang dapat timbul spontan. 90% kasus flutter atrium merupakan jenis tipikal dengan anticlockwise re-entry. Dilaporkan seorang laki-laki, 61 tahun dengan flutter atrium tipikal clockwise re-entry disertai pola disosiasi atrioventrikuler yang nyata dan bervariasi tanpa gambaran gelombang P sinusoid/gigi gergaji yang khas, sehingga hasil elektrokardiografi (EKG) pasien awalnya dianggap sebagai blok atrioventrikuler derajat tinggi. Gelombang P yang sinusoid khas flutter atrium baru terlihat jelas setelah pemberian salbutamol dan teofilin. Flutter atrium berhasil kembali menjadi irama sinus setelah salbutamol dan teofilin dihentikan dilanjutkan dengan pemberian digoksin. Disimpulkan bahwa diagnosis flutter atrium dapat didiagnosis hanya berdasarkan EKG sehingga untuk penatalaksaan kasus di runah sakit diperlukan pengalaman dan pemahaman komprehensif mengenai patofisiologi takiaritmia dan EKG.   Typical Atrial Flutter Mimicking High Degree Atrioventricular Block   Atrial flutter is one of the most common types of atrial tachyarrhythmias after atrial fibrillation. Atrial flutter is a form of tachyarrhythmias with a regular and increased atrial pulses, due to the activity of excessive atrial electrical activity characterized by an atrial pulse averaging 250 to 350 times per minute. The risk of atrial flutter always associated with a variety of certain medical conditions and only 2% of cases of atrial flutter can occur spontaneously. 90% of cases of atrial flutter are typical atrial flutter with anticlockwise re-entry. Here we present, a 61 years old male with a typical clockwise re-entry atrial flutter presenting a promienent and varied atrioventricular dissociation pattern without showing a sinusoidal / typical sawtooth P wave image, hence the patient’s electrocardiographic results were initially regarded as a high degree atrioventricular block. A typical sinusoid P waves of atrial flutter were then observed after administration of salbutamol and theophylline. In the end, the atrial flutter was succesfully converted into sinus rhythm after cessation of salbutamol and theophylline and administration of digoxin. In conclusion, the diagnosis of atrial flutter based solely on electrocardiography is a challenge that requires experience and a comprehensive understanding of the pathophysiology of the tachyarrhythmia and electrocardiography.