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IMAGES IN ELECTROPHYSIOLOGY

External Cardioversion ofSupraventricular Tachycardiain Omphalo-ThoracopagusConjoined Twins

M. Rizwan Afzal, MD,a Lindsey Malloy-Walton, DO,b Svjetlana Tisma-Dupanovic, MD,b

Andrea L. Miles, APRN,b Sanket Shah, MD,b John Papagiannis, MDb

A pair of omphalo-thoracopagus twins wasdiagnosed with supraventricular tachycardia(SVT) on the first day of life. Twelve-lead

FIGURE 1 ECG of Supraventricular Tachycardia

Two QRS populations are seen with a cycle length of 250 ms in twin A

From the aDivision of Cardiovascular Diseases, Cardiovascular Research Insti

Kansas City, Kansas; and the bDivision of Cardiology, Children’s Mercy Hospi

that they have no relationships relevant to the contents of this paper to dis

All authors attest they are in compliance with human studies committe

institutions and Food and Drug Administration guidelines, including patien

visit the JACC: Clinical Electrophysiology author instructions page.

Manuscript received June 16, 2016; revised manuscript received July 27, 201

electrocardiography was performed with leads placedon twin A (Figure 1). The 2:1 ratio of the 2 QRS popu-lations was thought to be the result of SVT in twin

(up-going arrows) and 500 ms in twin B (down-going arrows).

tute, University of Kansas Hospital & Medical Center,

tal, Kansas City, Missouri. The authors have reported

close.

es and animal welfare regulations of the authors’

t consent where appropriate. For more information,

6, accepted August 4, 2016.

FIGURE 2 Defibrillation Patch Placement

The thoracopagus twins with defibrillation patches placed in a

“back-to-back” configuration.

FIGURE 3 Cardioversion of SVT and ECG During Sinus Rhythm

(A) Termination of SVT with direct current shock. (B) 12-Lead ECG durin

Down-going arrows show the P and QRS waves of twin A and up-going

J A C C : C L I N I C A L E L E C T R O P H Y S I O L O G Y V O L . 3 , N O . 3 , 2 0 1 7 Afzal et al.M A R C H 2 0 1 7 : 3 1 0 – 2 External Cardioversion of SVT in Omphalo-Thoracopagus Conjoined Twins

311

A, with 1:1 conduction between the 2 atria and 2:1conduction at the level of the atrioventricular nodeof twin B. Intravenous adenosine (0.1 and 0.2 mg/kg) was given without success. External cardiover-sion was performed with defibrillation patches placedon the back of each neonate (Figure 2). The thoracopa-gus anatomy precluded anteroposterior placement ofdefibrillation patches. A synchronized shock of 6 Jsuccessfully restored normal sinus rhythm(Figure 3A). Repeat 12-lead electrocardiography aftercardioversion showed 2 different populations of Pand QRS waves with identical heart rates(Figure 3B). We concluded that the twin with thefaster sinus rate was driving the rate of the secondtwin through a connection at the atrial level. Theimaging studies, including contrast-enhancedcomputed tomography, revealed a complex relation-ship of the 2 hearts (Figure 4).

Electrocardiographic recording of thoracopagustwins has been rarely reported (1,2). SVT has beenpreviously reported in thoracopagus twins, withsuccessful ablation of the accessory pathway in 1of the twins (3). Because this is an extremelyrare occurrence, we present here the 12-lead

g sinus rhythm with insert showing the 2 sets of P and QRS waves.

arrows show the P and QRS waves of twin B.

FIGURE 4 Chest Radiograph and CT Angiogram of Twin Hearts

(A) Chest radiograph of twins with the combined heart mass outlined. (B) Chest CT of the twins showing the complex relationship of the

2 hearts. Twin A (lower of the 2 hearts) had totally anomalous pulmonary venous return with subdiaphragmatic drainage, atrial septal defect,

ventricular septal defect, and double outlet right ventricle, while twin B had normal cardiac anatomy. There was a communication between

the 2 right atria (not shown).

Afzal et al. J A C C : C L I N I C A L E L E C T R O P H Y S I O L O G Y V O L . 3 , N O . 3 , 2 0 1 7

External Cardioversion of SVT in Omphalo-Thoracopagus Conjoined Twins M A R C H 2 0 1 7 : 3 1 0 – 2

312

electrocardiogram of thoracopagus twins during SVTand during sinus rhythm. We also report successfulcardioversion with back-to-back placement of defi-brillation patches in thoracopagus twins for thefirst time.

ADDRESS FOR CORRESPONDENCE: Dr. John Papa-giannis, Children’s Mercy Hospital, Division of Car-diology, 2401 Gillham Road, Kansas City, Missouri64108. E-mail: jpapagiannis@cmh.edu.

RE F E RENCE S

1. Casta A. Cardiovascular evaluation in thor-acopagus twins. Circulation 1999;100:103.

2. Correa R, Shivapour J, Johnikin MJ, Walsh EP.WPW in conjoined thoracopagus twins. HeartRhythm 2014;11:336–7.

3. Correa R, Lang P, Walsh EP. Catheter ablation ofWolff-Parkinson-White syndrome in conjoinedthoracopagus twins. Heart Rhythm 2014;11:1070–2.

KEY WORDS cardioversion,electrocardiography, supraventriculartachycardia, thoracopagus twins