Sinus tachycardia occurs when the sinus mechanism is accelerated and the pattern of atrial and ventricular activation is normal.
The ECG is characterized by an atrial rate typically between 100 and 160 bpm, P waves with a normal configuration and axis, PR interval normal or slightly shortened, and a normal (baseline) QRS pattern. Occasionally, aberrant conduction within a bundle branch or fascicle may occur secondary to the increased rate. Therapy should be targeted at the underlying pathophysiologic process.
Beta-adrenergic antagonists may be used to slow the sinus te, particularly in the setting of myocardial ischemia.