Cardiac arrhythmias are one of the most prevalent cardiovascular causes of consult in the emergency room. The tachyarrhythmias have a broad clinical presentation spectrum with life-threatening implications in several cases, demanding an accurate and prompt diagnosis and initial treatment. The initial approach represents to determine the clinical stability of the patient. The electrocardiogram is the principal diagnosis tool and will divide the tachyarrhythmias in narrow or wide QRS complex, an aspect that guides the initial treatment. In wide QRS complex tachycardias, the main challenge during the diagnosis approach recognizes supraventricular tachycardias from ventricular tachycardias, and validated algorithms have been described as a tool to distinguish between these two types of arrhythmias. If the arrhythmia is not possible to be differentiated, it is recommended it be treated as ventricular tachycardia, especially in patients over 40 years and major risk factors to coronary artery disease. The initial treatment in stable patients with supraventricular tachycardia is vagal maneuvers and/or adenosine in bolus, which is effective to stop the arrhythmia and to figure out the auricular activity in atrial and flutter fibrillation. In unstable patients, the treatment of choice is electric cardioversion. Every tachyarrhythmia has different acute and maintenance therapy options that must be assessed depending on patient comorbidities and baseline medication. The reader will find practical elements for the early recognition of tachyarrhythmias, as well as examples and flowcharts for a fast-track evaluation. Also, you will find tables with drugs and doses that could facilitate the management in the emergency room.
