Principles of management Narrow complex tachycardia

Principles of management



If the patient is compromized, use DC cardioversion.
Otherwise, identify the underlying rhythm and treat accordingly. The chief thing is to decide whether the rhythm is regular or not (likely AF).
Vagal manoeuvres (carotid sinus massage, Valsalva manoeuvre) transiently increase AV block, and may unmask an underlying atrial rhythm.
If unsuccessful, give adenosine which causes transient AV block. It has a short half-life (10-15s) and works in 2 ways:
by transiently slowing ventricles to show the underlying atrial rhythm,
by cardioverting a junctional tachycardia to sinus rhythm.
Give 6mg IV bolus into a large vein, followed by saline flush, while recording a rhythm strip. If unsuccessful, give 12mg, then one further 12mg bolus.
Warn about SE: transient chest tightness, dyspnoea, headache, flushing. Relative CI: asthma, 2nd/3rd-degree AV block or sinoatrial disease (unless pacemaker). Interactions: potentiated by dipyridamole, antagonized by theophylline.