[Practical approximation to the diagnosis of tachyarrhythmias].

Even though the 12-lead electrocardiogram is the most helpful tool in the diagnosis of tachycardia, a careful history and physical examination can be useful in both differentiating between ventricular and supraventricular tachycardia and elucidating the electrophysiological mechanism of supraventricular tachycardia. This article will focus on the most relevant clinical aspects of tachyarrhythmias as well as on the electrocardiographic differential diagnosis of regular broad complex tachycardia.