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Atrial flutter with brief periods of junctional ectopic tachycardia

Islam Badr, M.Sc.; Rasha Kamel, MD; Osama Abdelaziz, MD; Gaser Abdelmohsen, MD; Maha Abdulaziz Mousa; Sameh Abdel Latif Abdel Salam, MD

Article Published: Jun 12, 2017
Islam Badr, M.Sc.*; Rasha Kamel, MD*; Osama Abdelaziz, MD**; Gaser Abdelmohsen, MD**; Maha Abdulaziz Mousa***; Sameh Abdel Latif Abdel Salam, MD****
 
* Fetal Medicine Unit, Cairo University, Egypt;
** Pediatric Cardiology Department; Cairo University, Egypt;
*** Department of Obstetrics & Gynecology; Cairo University, Egypt;
**** Radiology Department, Kasr Alainy Hospitals, Cairo University, Egypt.


Atrial flutter is characterized by an atrial rate between 250 – 500 bpm with atrioventricular block which may be fixed or variable and rarely paroxysms of 1:1 conduction 1 . Based upon the relationship between atrial contractions and their ventricular counterparts; fetal tachyarrhythmias can be classified into five types with atrial flutter representing type IV 2. Atrial ectopic tachycardia is classified as type II long VA tachycardia in this classification system 2. The most common AV relationship encountered in cases of atrial flutter diagnosed prenatally is 2:1 but occasionally 1:1 or 3:1 patterns are encountered 3. It is worth noting that atrial ectopic tachycardia associated with AV node dysfunction has been reported with alternating 1:1 and 2:1 AV conduction and prolonged VA interval during the periods of 1:1 conduction 2,3. In cases of tachycardia usually the forward venous flow becomes monophasic in the systolic and the early diastolic phases of the cardiac cycle with absent or reversed flow during the phase of atrial contraction 4. In atrial flutter, the amplitude of the atrial waves may alternate between high and low amplitudes according to their relationship with the ventricular waves 4. The association between more than one type of tachyarrhythmia may raise the suspicion of the diagnosis of sick sinus syndrome but a bradyarrhythmia should be present for the diagnosis (tachy-brady syndrome) 5. 
 

Case report 

A 30-year old pregnant lady at 32 weeks of gestation presented to the emergency department complaining of preterm labor pain. Ultrasound examination performed in the emergency department revealed the presence of persistent tachyarrhythmia associated with hydrops and the lady was referred to our unit.

Our ultrasound examination confirmed the presence of severe ascites together with polyhydramnios. There was hepatomegaly with edematous liver and congested inferior vena cava. Fetal echocardiography failed to reveal any structural heart defect. Fetal tachyarrhthmia was observed with the fetal heart rate estimated to be around 240 bpm throughout the whole scan period. The atrial rate was around 480 bpm with 2:1 AV conduction resulting in a ventricular rate of about 240 bpm. The atrial contractions varied in their amplitude according to their relationship with the ventricular contractions being higher in amplitude in case of simultaneous occurrence with the ventricular contractions. In brief periods, 1:1 atrioventricular conduction was observed with both the atrial rate and ventricular rate estimated to be around 240 bpm. During those brief periods, atrial and ventricular contractions were occurring simultaneously and overlapping upon each other both in m-mode and pulsed wave images. Based on the above-mentioned findings, our diagnosis was atrial flutter with 2:1 conduction with brief periods of junctional ectopic tachycardia. 

Carvalho et al. have reported three cases of atrial flutter among 15 cases of supraventricular tachycardia, the atrial rate in their cases ranged between 450-500 bpm with 2:1 AV conduction and alternating low and high amplitude atrial contractions 4. Differentiation between atrial flutter and atrial ectopic tachycardia may be challenging in some cases based on fetal echocardiographic interrogation. Atrial ectopic tachycardia is usually diagnosed based on a long VA interval with a rate usually between 180-220 bpm 2,4 however a short VA interval with alternating 2:1 and 1:1 atrioventricular conduction due to AV node dysfunction has been reported 2,3 . Atrial tachycardia was reported with intermittent episodes of tachyarrhythmia alternating with episodes of atrial bigeminy causing bradycardia and this association with atrial ectopic beats should pay attention to atrial ectopic tachycardia as a possible diagnosis 4. It is also worthnoting that a long VA tachycardia with sudden onset and arrest and which is initiated by an atrial extrasystole may also suggest the presence of junctional reciprocating tachycardia 2 . Junctional ectopic tachycardia is diagnosed by simultaneous onset of atrial and ventricular contractions 2. We are aware of a case report by Fouron et al. in which junctional ectopic tachycardia was alternating with episodes of ventricular tachycardia leading to the final diagnosis of congenital junctional ectopic tachycardia 4  however atrial flutter in our case was electrically confirmed postnatally by an ECG. The relationship between atrial and ventricular contractions in our case being simultaneous in the brief periods of 1:1 AV conduction, does not allow for the diagnosis of 1:1 AV conduction in atrial flutter.     



Videos 1, 2 and 3: Shows the tachyarrhythmia , the severe ascites, the polyhdramnios, the enlarged congested edematous liver and the enlarged IVC.


Image 1: M-mode tracing of right atrium and left ventricle showing atrial contractions (white arrows) and ventricular contractions (red arrows). The atrial rate is approximately 480 bpm and the ventricular rate is around 240 bpm (2:1 atrioventricular block).

Image 1

Image 2: Simultaneous pulsed wave tracing of both pulmonary artery and vein showing the atrial contractions (white arrows) and ventricular contractions (red arrows) with 2:1 atrioventricular block.

Image 2

Image 3: Pulsed wave tracing of simultaneous pulmonary artery and vein (above) and a hepatic vein (below) showing the different amplitudes of atrial contractions according to their relationship with the ventricular contractions. Note that atrial contractions occurring during ventricular contractions have higher amplitude (red line) while those occurring away from ventricular contractions have lower amplitude (white line). Connecting the rest of atrial contractions by lines are not feasible due to different sweep speeds in both traces.

Image 3

Images 4: Simultaneous pulsed Doppler tracing of both renal artery and vein. Note that the atrial contractions occurring during ventricular contractions are of higher amplitudesBrief periods of 1:1 atrioventricular conduction were noted as shown in images 5,6,7 and 8.

Image 4

Image 5: M-mode tracing of both atrial and ventricular contractions showing a brief period of 1:1 atrioventricular conductions with both rates estimated to be around 240 bpm. Note that the peaks of atrial contractions coincide with the peak of ventricular contractions but this more evident in the pulsed wave tracing.

Image 5

Images 6 and 7: Showing the simultaneous atrial and ventricular contractions in renal artery and vein with both waveforms are overlapping upon each other.

Image 6
Image 7

Image 8: Reversed flow in hepatic veins due to atrial contractions at the brief periods of 1:1 atrioventricular conduction. Note that all the atrial contractions are of high amplitude due to the simultaneous occurrence with the ventricular contractions .

Image 8

Image 9: ECG showing the characteristic atrial flutter waves in lead III (arrows), atrial rate 350-360/min and ventricular rate 220/min.

Image 9


References

1. Oudijk MA, Visser GHA, Meijboom EJ. Fetal Tacyarrhythmia – Part I: Diagnosis. Indian Pacing Electrophysiol J. 2004; 4: 185-194

2. Fouron JC. Fetal arrhythmias; the Saint-Justine hospital experience. Prenat Diagn 2004; 24: 1068-1080

3. Fouron JC, Fournier A, Proulx F, Lamarche J, Bigras JL, Boutin C, Brassard M, Gamache S. Management of fetal arrhythmia based on superior vena cava/aorta Doppler flow recordings. Heart 2003; 89: 1211-1216

4. Carvalho JS, Prefumo F, Ciardelli V, Sairam S, Bhide A, Shinebourne EA. Evaluation of fetal arrhythmias from simultaneous pulsed wave Doppler in pulmonary artery and vein. Heart 2007; 93: 1448-1453

5. Semelka M, Gera J, Usman S. Sick sinus syndrome: a review. Am Fam Physician 2013; 87: 691-696

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