Differential Diagnosis and Management of Narrow Complex Irregular Tachycardia
| Arrhythmia | Comment | Management |
|---|---|---|
| Atrial fibrillation | Difference between maximum and minimum instantaneous heart rates, calculated from the shortest and longest RR intervals is usually >30/min | See Chapter 43 |
| No organized atrial activity evident: fibrillation waves of varying amplitude may be seen | ||
| Atrial flutter with variable AV conduction | Often associated with structural heart disease | See Chapter 43 |
| Vagotonic manoeuvres and adenosine slow the ventricular rate to reveal flutter waves (‘saw-tooth’ flutter waves in inferior limb leads) | DC cardioversion if there is haemodynamic instability. | |
| In stable patient, aim for rate control with AV node-blocking drugs (Table 42.4) | ||
| Discuss further management with a cardiologist | ||
| Multifocal atrial tachycardia | Irregular tachycardia, typically 100–130/min, with P waves of three or more morphologies and irregular PP interval | Treatment is directed at the underlying disorder and correction of hypoxia/hypercapnia |
| Most commonly seen in COPD | Consider verapamil if the heart rate is consistently over 110/min | |
| DC cardioversion is ineffective |
AV, atrioioventricular; COPD, chronic obstructive pulmonary disease.