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Atrial bigeminy

Sinus Rhythm With Atrial Bigeminy

Tue, 07/07/2015 - 17:56 -- Dawn

This ECG is from an 88-year-old man with congestive heart failure.  No other clinical information is known.  It shows an underlying sinus rhythm with atrial bigeminy - every other beat is a premature atrial contraction.  There is very little, if any, difference in the morphology of the sinus P waves and the ectopic P waves, indicating that the ectopic focus is in the vicinity of the sinus node.  There is no "compensatory" pause, because PACs penetrate the sinus node, resetting it.  So, the underlying sinus rate here is about 72 beats per minute.  There are several mechanisms for bigeminy to occur, but ectopic bigeminy is the most common.

jer5150's picture

Jason's Blog: ECG Challenge for the months of July and August, 2014.

This is an ECG I performed a couple of years ago on an asymptomatic 83-year old man as an outpatient procedure. 

The computer interpreted this as:  "Marked sinus bradycardia [with] Frequent Premature ventricular complexes".  IS THE COMPUTER CORRECT?  Is there more than one plausible interpretation?  What is the differential diagnosis?

Bigeminal Rhythm

Sat, 09/07/2013 - 02:09 -- Dawn

To continue a recent theme, we offer this ECG, which appears on quick glance to be an atrial bigeminy.  On closer inspection, we do not see ectopic P' waves in the second conducted beats of each pair.  In fact, the P waves look the same in both the first and second beats. However, if you look very closely (we enlarged the screen), you may notice that the second T wave of each pair is slightly larger with a slightly different morphology than the first T wave.  If this distortion of the second T waves represents a PAC, the PAC is non-conducted and concealed in the T wave. If that concealed P wave is able to penetrate and depolarize the sinus node, we might expect the sinus node to be reset, and the next P wave and QRS combination is right on time.

So, what looks like an "atrial bigeminy" might actually be an "atrial trigeminy" - albeit with non-conducted PACs.

Also notable is the subtle ST elevation in V1, V2, and V3, which should be evaluated with clinical data. Unfortunately, we do not have information about the patient.  Also, V2 and V3 do not represent normal or expected R wave progression.  The chest leads should have rS patterns, and they should progress from small r waves and deep S waves in V1 with gradually taller R waves and shorter S waves across the chest wall.  V6 should be, finally, all upright.  We suspect lead reversal between V2 and V3, or misplacement of the electrodes in general.  Also, the q waves in those leads seem misplaced, without the usual configuration of pathological Q waves in those leads.

We would love to hear your opinions about this interesting rhythm.


ECG Basics: Sinus Rhythm With Atrial Bigeminy

Sun, 06/30/2013 - 03:22 -- Dawn

This is a normal sinus rhythm with atrial bigeminy, a term meaning that every other beat is a PAC.  If you look carefully, you can see slight differences in the sinus P waves and the atrial (premature) P waves.  The PACs penetrate and reset the sinus node, causing what looks like a delay after the PAC.  It is often just a return to the normal P to P interval, or nearly so.  If you teach basic students in a clinical setting, they will learn from palpating the peripheral pulse and feeling the pattern of bigeminal beats. Sometimes, the premature beat feels much weaker due to less filling time available to the ventricles.  Atrial bigeminy can have very benign causes, such as increased caffeine intake, or it can have more complex causes such as advanced heart disease or conduction blocks.  In some patients, atrial bigeminy, or any PACs, can be a precursor to more serious atrial dysrhythmias, such as atrial fibrillation.

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Jason's Blog: ECG Challenge of the Week for March 31st - April 7th.

Patient's clinical data:  66-year-old white man.

Amongst the computer's several statements was the interpretation of "Undetermined rhythm".  To the computer's statement, the reviewing cardiologist added the freehand text of "Abnormally slow" but failed to provide a diagnosis.   

What is accounting for this pattern?

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Jason's Blog: ECG Challenge of the Week for July 8-15. Which lead do both of these ECGs share a “common-thread”?


Two more ECGs classified under the general heading:  “Tracing suggestive of   ____ ”.  I  like ECGs that strongly favor a very specific clinical disorder.

Recently I performed these ECGs on two different patients.  They were both recorded a little more than an hour apart and exemplified a common electrocardiographic theme I noticed during that work shift.

The primary goal of this week’s blog is not to determine the name of each ECG’s rhythm but rather what each ECG is virtually diagnostic of.

This sign is commonly referred to by one of two names:  (1.)  Either by the lead that it appears in or (2.) eponymously named after the doctor who is credited with first describing it.  

Sinus Rhythm With Non-Conducted Atrial Bigeminy

Tue, 06/26/2012 - 22:02 -- Dawn

Jason's Blog: ECG Challenge of the Week, 6-8-12     INTERPRETATION:


1)  In first half of strip: Normal sinus rhythm (rate = 100/min) with . . .

2)  . . . bifascicular block—right bundle-branch block plus left anterior hemiblock 

      (RBBB + LAHB), left axis deviation (LAD) at -57 degrees.

3)   In second half of strip: Sinus rhythm interrupted by a run of nonconducted atrial bigeminy  (arrows (↓); see laddergram).


Jason E. Roediger, CCT, CRAT

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