Narrow-complex tachycardia.

The term "narrow-complex tachycardia" is applied to a number of common and rare arrhythmias. Atrial fibrillation is the narrow-complex tachycardia most frequently seen in clinical practice. Sinus tachycardia is associated with underlying metabolic abnormalities, and paroxysmal atrial tachycardia most often results from digitalis toxicity. Multifocal atrial tachycardia usually occurs in older adults with chronic obstructive pulmonary disease. Atrioventricular nodal reentrant tachycardia is commonly found in otherwise healthy children and adolescents. The initial diagnosis should be reconsidered if drug therapy is unsuccessful, because differences in rhythm disturbances are often subtle. Radiofrequency catheter ablation is an effective treatment for atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia (Wolff-Parkinson-White syndrome) and the permanent form of junctional reentrant tachycardia. Catheter ablation should also be considered in difficult cases of atrial flutter, intra-atrial reentry and automatic atrial tachycardia.