However, it can also occur in people without heart damage.

Atrial fibrillation (Afib): This type of rapid heart rate can occur in people with congenital heart conditions or in people who have heart damage from high blood pressure, heart disease, or heart attack.It may be more common in people with dysautonomia (an automatic nervous system disorder). Doctors sometimes misdiagnose this as anxiety. Inappropriate sinus tachycardia (IST): This irregular heart rhythm is generated in the sinus node and is not detectable on an ECG.When there is not an identifiable natural trigger, there may be an underlying medical condition.

Sinus tachycardia: This usually occurs as a result of exercise, illness, and anxiety.

Focal atrial tachycardia (Focal AT): This type is characterized by rapid heartbeat and usually affects people with too many catecholamines, a toxic reaction to digoxin (heart medication), congenital heart disease, and cardiomyopathy (heart muscle disease).

Of note, atrial flutter is very sensitive to cardioversion often only requiring 50-100 J. Treatment is very similar to Atrial Fibrillation. But briefly, the options include cardioversion, rate-control and +/- anticoagulation. Treatment options to be discussed in more detail in a following conference. Adenosine can also unmask the underlying flutter. You can attempt vagal maneuvers to either convert to NSR or cause unmasking of flutter waves. Of note, SVT typically presents with HR 170-250. If the rate is faster (e.g HR 160-175), it can resemble SVT as P waves become buried in the frequent QRS complexes. Also Atrial flutter patients are often stable, and therefore, there is time to work up the EKG Therefore, in any regular narrow-complex tachycardia with HR 130-170, it is important to consider atrial flutter. HR 125-140, it can resemble Sinus Tachycardia. The same is true for vagal maneuvers which may transiently unmask the flutter waves (though more commonly will cause no changes) Atrial Flutter after AV Nodal Blocking with Adenosine From Dr. The good news is that adenosine only lasts 10-15 seconds, and ventricular contractions will continue thereafter. If we confused the first EKG with SVT, and gave adenosine (AV nodal blocking agent), we would see the continuation of flutter waves, but no QRS depolarizations due to the AV nodal blocking properties of adenosine (seen in EKG below). This also gives a much better “saw-tooth” appearance which we remember from our Med School rhythm strips seen in FirstAid (as below) Examples of 2:1 Block, 3:1 Block, and 4:1 Block from medications or underlying heart disease), you can see a 3:1 or 4:1 block, which corresponds to the number of P waves prior to the QRS. If there is a higher-degree block (e.g.

This most often leads to a 2:1 AV ratio block meaning for every two P waves produced, a QRS will form (as seen above) which often produces a ventricular rate (QRS) of HR roughly 150. The AV node acts as the electrical gateway between the atria and ventricle, and has long refractory period allowing it to “block” excessive depolarizations from the atria Since it originates from the atria, the heart rate will resemble the atrial rate, most often ~150 bpm (though there can be variability person-to-person with average range 130-170) Type of supraventricular tachycardia caused by re-entry circuit within the right atrium Clues to this are the saw-tooth appearance caused by the flutter waves, HR of roughly 150, and P waves that march out at a rate of roughly 300. You could also consider Atrial Ectopic Tachycardia (more commonly seen in peds), however, it is a rarer diagnosis compared to above.ĭrumroll… This is Atrial Flutter. This should lead us to a differential including Sinus Tachycardia, SVT (AVNRT vs. Now we just need to decide which type of Regular Narrow-Complex Tachycardia. However, the big takeaway from this EKG is that it is a Regular Narrow-Complex Tachycardia with HR roughly 150. You’re handed this EKG from triage.Īs always, it is important to approach an EKG in a systematic way including rate, rhythm, axis, intervals, and segments. The 5-minute EKG was presented by our fan-favorite attending, Dr.

Atrial flutter vs svt