Final answer:
Narrow or wide complex tachycardia refers to the appearance of QRS complexes on an ECG. Narrow complex tachycardia has a QRS duration less than 120 ms, while wide complex tachycardia has a QRS duration greater than or equal to 120 ms. Differentiating between the two is crucial for determining the underlying cause and treatment approach.
Step-by-step explanation:
In the context of tachycardia, narrow or wide complex indicates the appearance of QRS complexes on an electrocardiogram (ECG). Narrow complex tachycardia (NCT) is characterized by a QRS duration less than 120 ms, while wide complex tachycardia (WCT) has a QRS duration greater than or equal to 120 ms.
It is important to differentiate between NCT and WCT as their underlying causes and treatment approaches differ. NCT is often caused by supraventricular arrhythmias such as atrioventricular nodal reentrant tachycardia (AVNRT) or atrioventricular reentrant tachycardia (AVRT). On the other hand, WCT can be caused by ventricular arrhythmias like ventricular tachycardia.
Further evaluation with a comprehensive history, physical examination, and additional tests such as an ECG, echocardiogram, or electrophysiological study is necessary to determine the specific diagnosis and appropriate treatment for narrow or wide complex tachycardia.