As mentioned earlier, it is sometimes difficult to identify the flutter waves when they merge with the beginning or end of the QRS complex or lie within the QRS complex. In these situations, it may be difficult to determine whether the rhythm is sinus tachycardia, ectopic atrial tachycardia or atrial flutter with 2:1 AV block.
The tracing shown here illustrates a narrow complex tachycardia with a ventricular rate is 135. Take a minute to decide if the rhythm is atrial flutter with 2:1 AV block or an atrial tachycardia with 1:1 AV conduction..