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Atrial flutter

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Dawn's picture

Inferior Wall M.I. With Atrial Fibrillation or Atrial Flutter

Sat, 02/23/2019 - 22:17 -- Dawn

The Patient   This ECG was obtained from a 74-year-old man who had a history of COPD. He was complaining of severe chest pain at the time of the ECG.

The ECG     The rhythm is atrial fib or flutter (the R to R intervals are irregular, but seem to repeat about 4 interals).  Flutter waves are seen during some of the longer intervals. The rate is approximately 90 beats per minute.  The ST segments are very noticeably elevated in Leads II, III, and aVF.  There is reciprocal ST depression in Leads I and aVL, and also in all the precordial leads. 

Dawn's picture

ECG Basics: Atrial Flutter With 2:1 Conduction And An Aberrantly-conducted Beat

Sun, 08/23/2015 - 12:20 -- Dawn

This strip was taken from a patient at rest.  It shows a regular tachycardia with a slightly-widened QRS complex at about .10 seconds duration.  It is somewhat difficult to evaluate the baseline for P waves or flutter waves.  We ALWAYS recommend multi-lead assessment for such evaluation.  The P waves (or flutter waves) here have a sharp point, and can be easily "marched out", with a rate of about 300 per minute.

Whenever the ventricular rate is near 150/min., we should always consider the possibility of atrial flutter with 2:1 conduction.  Since atrial flutter results in atrial depolarization at around 250 - 350 per minute, conducting every other P wave results in a rate of about 150.  It can masquerade as sinus tach, but a patient with sinus tach at such a fast rate would probably have an obvious cause for a rapid heart rate, such as hypovolemia, drug overdose, or exertion.  This rhythm could also be mistaken for atrial tachycardia or other forms of supraventricular tachycardia (SVT, PSVT, AVNRT, etc.).   Multiple leads can more easily uncover the flutter waves running continuously "behind" and "through" the QRS complexes.

There is one beat that is obviously different from the others.  This beat is about the same width as the other QRS complexes, but is opposite in direction.  This probably represents aberrant conduction, possibly a hemiblock that occurs only in this beat.  Careful measurement will show that this QRS is very slightly early, while the others are all very regular. The slight width of all the QRS complexes suggests that there is a conduction delay, which cannot be diagnosed on one strip with no patient history available.

There are other differential diagnoses, such as ventricular tachycardia with a captured sinus beat.  We welcome discussion of this interesting strip. 

Dawn's picture

Atrial Flutter With Variable Conduction

Sun, 06/21/2015 - 11:31 -- Dawn

This is a good example of atrial flutter with variable conduction in a 53-year-old man.  He had been treated for a fast rate, and now has a rate of approximately 90 per minute.  No other clinical information is available.  One of the good teaching points in this ECG is that some leads show P waves (or, in this case, flutter waves) better than others.  The diagnosis of atrial flutter can be missed by practitioners utilizing only one or two leads.

The typical flutter waves, at a rate close to 300 / min., can best be seen in Leads II, III, aVF, aVL, V1, and V3.   Leads II and aVF are especially good for teaching students to "march out" the flutter waves through the entire strip.  They can be seen in the QRS complexes and T waves in these leads.

Because atrial flutter often accompanies a diagnosis of congestive heart failure, this is a good ECG for teaching the contribution of rate - atrial and ventricular - in the workload and cardiac output of the patient.

Dawn's picture

Atrial Flutter With Variable Conduction

Tue, 11/04/2014 - 00:24 -- Dawn

This ECG provides an example of atrial flutter with variable conduction.  There are two distinct R - R intervals, making this a somewhat regularly-irregular  rhythm, as opposed to the irregular irregularity of atrial fibrillation.  The flutter waves (P waves) are very easy to see in most leads, but not in all.  If you are teaching students who are making the transition from reading monitors and rhythm strips to 12-lead ECGs, this is a great ECG to illustrate for them how the more leads you have, the more you will see.  The flutter waves are invisible in Lead I and, to the untrained eye, they may be hard to see in the precordial leads.  The four channels on this ECG are run simultaneously, so if  P waves or flutter waves are visible in one lead, they are also present in all leads that line up vertically with that one.  In other words, the Lead II rhythm strip at the bottom confirms that flutter waves exist across the entire ECG.

The R - R intervals in this ECG reflect alternating 2:1 and 4:1 conduction.  There are a couple of times when the 4:1 ratio repeats itself without alternating.  Often, the length of these varying R - R intervals will be multiples of each other, or have a common denominator.  These do not appear to, and may reflect the fact that, when R to P intervals lengthen, R to R intervals sometimes shorten.  In other words, the PR intervals, which are difficult to measure in atrial flutter, may be changing.  I would invite my colleagues with more expertise in this area to comment below.

There are no blatant ST segment abnormalities here, but ST segments can be very difficult to assess in atrial flutter because of the flutter waves.  We do not have clinical data, other than this is a 62-year-old man.

Dawn's picture

ECG Basics: Atrial Flutter With 2:1 Conduction Ratio, Rhythm strip

Thu, 07/17/2014 - 15:40 -- Dawn

One of the most frequently misdiagnosed rhythms, atrial flutter with 2:1 conduction often masquerades as sinus tach.  Sinus tach usually has an obvious cause, such as exercise, severe hypovolemia, or age less than 6 months.  Atrial flutter usually produces flutter waves (P waves) at a rate of 250 - 350 per minute.  Therefore, a 2:1 conduction ratio would result in a heart rate of about 125 - 175 bpm).  

Often, students are taught about atrial flutter using an electronic rhythm generator or a book with limited illustrations, and they become acustomed to seeing atrial flutter with 3:1 or 4:1 conduction.  The flutter waves are very easy to see in such a situation.  However, the AV node, if not affected by medication, is usually well able to conduct at a rate of 150 or more.  Therefore, the physiological block that protects us from extreme rates will keep the heart rate around 150 bpm in atrial flutter.

This is a single rhythm strip.  It can be VERY helpful to look at multiple leads to look for flutter waves.  See this week's Instructors' Collection ECG of the WEEK for the SAME patient's 12-Lead ECG.  Also, your students should be reminded that sinus rhythms, including sinus tach, tend to change rates based on the needs of the patient.  For example, as a patient is treated for his/her condition, the rate may improve by slowing.  Conversely, if the condition becomes worse, or the patient is stressed, the rate may increase.  Atrial flutter, like all re-entry tachycardias, tends to stay at a steady rate unless the conduction ratio changes.

Show your students that the flutter waves are CONTINUOUS.  That is, they don't pause for the QRS.  The second illustration shows the flutter waves highlighted, to aid in seeing the continuous line of flutter waves.

Dawn's picture

Atrial Flutter With 2:1 Conduction

Thu, 07/17/2014 - 14:32 -- Dawn

One of the most frequently misdiagnosed rhythms, atrial flutter with 2:1 conduction often masquerades as sinus tach.  Sinus tach usually has an obvious cause, such as exercise, severe hypovolemia, or age less than 6 months.  Atrial flutter usually produces flutter waves (P waves) at a rate of 250 - 350 per minute.  Therefore, a 2:1 conduction ratio would result in a heart rate of about 125 - 175 bpm).  Often, students are taught about atrial flutter using an electronic rhythm generator or a book with limited illustrations, and they become acustomed to seeing atrial flutter with 3:1 or 4:1 conduction.  The flutter waves are very easy to see in such a situation.  However, the AV node, if not affected by medication, is usually well able to conduct at a rate of 150 or more.  Therefore, the physiological block that protects us from extreme rates will keep the heart rate around 150 bpm in atrial flutter.

This ECG shows two instances where the conduction ratio slows to 3:1 momentarily, at beats no. 3 and 20.  This makes the atrial flutter more apparent.  Students should be taught to check multiple leads in any patient with a heart rate of between 125 bpm and 175 bpm, and look for flutter waves.  Flutter waves are continuous - they do not "pause" for the QRS.  For a rhythm strip with the flutter waves highlighted, see this patient's rhythm strip.

 

Dawn's picture

Atrial Flutter With 2:1 Conduction And Left Bundle Branch Block

Sun, 05/11/2014 - 22:10 -- Dawn

This ECG is a two-for-one teaching opportunity.  This elderly woman presents with a tachycardia at about 120/min.  We do not have any other information about her complaints or past medical history.

Her ECG shows a wide-complex tachycardia.  The QRS complexes are about 124 ms (.12 sec.) wide.  On the most basic level, we should teach our students to consider ALL wide-complex tachycardias to be ventricular tachycardia until proven otherwise.  This ECG has many clues that it is NOT ventricular tachycardia.  Tiny P waves can be seen in V1, V2, and V3.   But, these are not the only P waves.  The atrial rate in this case is twice the ventricular rate, making the rhythm ATRIAL FLUTTER with 2:1 conduction.  The flutter rate is about 240/minute, slightly on the slow side for AFL.  Atrial flutter with 2:1 conduction is often missed, as every other P wave is hidden.  Look at aVR and Lead II in this case for signs of the regular flutter waves.  It is important to look in all 12 leads for signs of flutter waves in any tachycardia over 120/min.  Occasionally, you will get lucky, and the patient will conduct at a different ratio, such as 3:1 or 4:1, making the flutter waves much more visable.  Sometimes, the atrial flutter becomes apparent during carotid sinus massage or a Valsalva maneuver.

The QRS width, in this case, is due to left bundle branch block.  The criteria for LBBB are:  Wide QRS, Supraventricular Rhythm (in this case, atrial flutter), and a negative QRS in V1 with a positive QRS deflection in Leads I and V6.  The ST changes seen here are typical of LBBB:  ST depression in leads with upright QRS complexes and ST elevation in leads with downward QRS complexes.

 

Dawn's picture

ECG Teaching Series: Atrial Flutter

Fri, 02/07/2014 - 22:54 -- Dawn

In the first ECG shown, we see an irregular tachydysrhythmia.  He has had periodic episodes of rapid heart rate since the age of 19, but is in good health otherwise.  He is on Flecainide, 200 mg per day.   The rhythm might look like atrial fibrillation to many people, but there are signs of regular, fast flutter waves (arrows).  The irregularity is caused by variable conduction of the atrial flutter.  The QRS is slightly widened, possibly due to the Flecainide, a sodium-channel blocker which slows conduction.

The patient usually felt palpitations during these periods of rapid heart rate, but had no syncopal episodes, chest pain, or other concerning symptoms.

 

The next ECG shows more apparent flutter waves.  The ST elevation is due to artifact which can occur on manually-obtained ECGs due to the type of filtering.  It is not uncommon to see dramatic ST elevation on manually-obtained rhythm strips which disappears when a standard filtered 12-Lead is performed.   On other ECGs, the patient also had periods of NSR and frequent PACs. (ECGs not shown).

 

The third ECG was obtained after the patient underwent successful radiofrequency ablation for atrial fib / atrial flutter.  He is now off antiarrhythmics, and feeling well.

For instructors and students, this is a nice "before and after" series to illustrate successful ablation.

Dawn's picture

Supraventricular Tachycardia

Thu, 01/02/2014 - 13:36 -- Dawn

This example of supraventricular tachycardia is from a 51-year-old woman who presented to the Emergency Dept. with a complaint of palpitations.  We do not have any more clinical information for her.  We know this tachycardia is supraventricular because the QRS complexes are narrow.  The term, "supraventricular tachycardia", or "SVT" actually describes many different rhythms with many different mechanisms and causes.  It would help a great deal to see the beginning (or end) of this rhythm to determine if the onset was sudden (paroxysmal) - or gradual.  Sinus rhythms tend to speed up gradually - picture a patient on a treadmill getting a faster and faster heartrate.  Take the patient off the treadmill, and the rate gradually decreases.  This reflects normal function of the sinus node.

SVT with paroxysmal onset indicates a re-entry mechanism, where the impulse travels from the atria to the ventricles by one pathway, but is able to return in a retrograde fashion, following a second pathway in the atria or AV node, and reenter the ventricles, depolarizing them antegradely, causing another QRS.  The atria are usually depolarized retrogradely as well.   Reentry can occur in the sinus node, in the AV node, or around the AV node via accessory pathways in the atria.  For a very clear and concise discussion of AV nodal reentry tachycardia (AVNRT), go to this Life in the Fast Lane link.  There is also a great discussion of AVNT and pre-excitation syndromes, including Wolff-Parkinson-White syndrome, at LITFL.

In this ECG, we do not know the patient's clinical situation,  and we haven't seen the onset of this rhythm.  The rate is 166 / min.  In order for her sinus node to naturally reach this rate, we can assume she would have some visible reason for tachycardia:  extreme anxiety, blood loss, hypoxia, exercise, etc.  An "inappropriate" sinus tachycardia is a possibility, but not the most common thing.  If she describes this rhythm as having a sudden onset, the most common and most likely diagnosis is AVNRT, also called SVT or PSVT.  

The presence of retrograde P waves can aid in the diagnosis of AVNRT.  Retrograde P waves are negative in Leads II, III, and aVF.  They can occur before, during, or after the QRS.   In this ECG, we cannot see P waves, either before or after the QRS.  Some of the QRS complexes (limb leads) have a small notch at the end, but it does not look like a typical retrograde P wave in II or aVF.

If sinus tachycardia can be ruled out, it is safe to treat this rhythm with Valsalva maneuvers and adenosine, and then investigate the cause.

Dawn's picture

ECG Basics: Atrial Flutter With Variable Conduction

Thu, 10/10/2013 - 21:02 -- Dawn

This is a good teaching strip for showing your students how to "see" the atrial activity separately from the ventricular activity.  The P waves, also called flutter waves, march out regularly at a rate of around 300/minute, which is typical of atrial flutter.  The conduction ratio is variable, and the intervals between the conducted P waves and the QRS complexes vary, as well, reflecting changing refractoriness of the AV node.  It is easy with this strip to "march out" the flutter waves, through the QRS complexes, and to show your students how the flutter waves are either visible, or "hiding" behind a QRS complex.  We have featured several atrial flutter examples on the ECG Guru recently.  Remember, you can also obtain rhythm strips for your basic students by cropping out the rhythm strips often found at the bottom of 12-lead ECGs.

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