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Year : 2021  |  Volume : 11  |  Issue : 3  |  Page : 185-187

Frog sign and AV nodal reentrant tachycardia: A case report

1 Departments of Internal Medicine, St. Luke's University Hospital – Internal Medicine, Fountain Hill, Easton, PA, USA
2 Department of Medicine, St. Luke's University Hospital/Temple St. Luke's Fountain Hill, Easton, PA, USA
3 Research, St. Luke's University Hospital, Fountain Hill, Easton, PA, USA
4 Department of Internal Medicine, St. Luke's Hospital – Anderson, Easton, PA, USA
5 Independent artist
6 Cardiology, St. Luke's University Hospital, Fountain Hill, Easton, PA, USA

Date of Submission15-Jul-2020
Date of Acceptance25-Jan-2021
Date of Web Publication25-Sep-2021

Correspondence Address:
Dr. Sudip N Nanda
Department of Cardiology, St. Luke's Hospital, 801 Ostrum Street, Bethlehem, PA 18015
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJCIIS.IJCIIS_118_20

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Supraventricular tachycardia is one the most frequent cardiac arrhythmias seen in patients, with AVNRT being the most common subtype. Two subgroups of AVNRT have been reported, that of typical and atypical. “Frog Sign,” long considered a classic physical exam sign, albeit rare, is associated with typical AVNRT. We present a case of a patient who presented with frog sign and ultimately was determined to have AVNRT. Knowledge of “frog” sign aids clinical diagnosis and correct treatment.

Keywords: AV nodal reentrant tachycardia, case reports, electrophysiology, supraventricular tachycardia

How to cite this article:
Krinock M, Stone L, Yellapu V, Amaratunga E, Parameswaran A, Krinock G, Nanda SN. Frog sign and AV nodal reentrant tachycardia: A case report. Int J Crit Illn Inj Sci 2021;11:185-7

How to cite this URL:
Krinock M, Stone L, Yellapu V, Amaratunga E, Parameswaran A, Krinock G, Nanda SN. Frog sign and AV nodal reentrant tachycardia: A case report. Int J Crit Illn Inj Sci [serial online] 2021 [cited 2021 Dec 9];11:185-7. Available from: https://www.ijciis.org/text.asp?2021/11/3/185/326593

   Introduction Top

Supraventricular tachycardia (SVT), with the most common type known as atrioventricular nodal reentry tachycardia (AVNRT), is defined as a tachycardia that generates above the bundle of HIS.[1] “Frog sign” long considered a classic physical exam sign, has been reported to aid in the diagnosis of typical AVNRT.[2] Although, a somewhat rare physical exam sign, knowledge of this sign as well as its pathophysiology helps to ensure the proper management of patients who present with typical AVNRT.

   Case Top

A 53-year-old male presented to the emergency department (ED) complaining of palpitations and chest pain. The patient admitted to stopping his prescribed metoprolol 6 months before arrival. History was significant for Marfan syndrome, AVNRT, and previous tobacco abuse. Family history was notable for a maternal grandfather with Marfan syndrome. Social history was negative for alcohol or drug use. No previous genetic testing had been performed. Vital signs on presentation were notable for a pulse of 199 beats/min, blood pressure of 120/80 mm Hg, temperature of 37.6°C, respirations of 18 breaths/min, and oxygen saturation of 95% on room air. Physical examination demonstrated bilateral, pulsatile, bulging jugular veins consistent with “frog sign” [Figure 1]. The patient exhibited arachnodactyly and scoliosis. Electrocardiogram (EKG) showed a narrow complex tachycardia with a retrograde “P” embedded in the QRS in V1, and retrograde “P” waves in inferior leads (II, III, and aVF) consistent with atrioventricular nodal reentry tachycardia (AVNRT) [Figure 2]. Given the history of Marfan syndrome, concern for dissection was present. A computed tomography angiogram of the chest and abdomen was ordered which revealed no evidence of dissection but showed severe scoliosis. Troponin I was 0.00 ng/ml. The basic metabolic panel was within normal limits. Magnesium was 2.3 mg/dL. Complete blood count was notable for a white blood cell count of 13.48 K/uL. The patient received a total of 24 mg of intravenous (IV) adenosine in the ED, converting to sinus rhythm. The patient had recurrence of AVNRT once admitted to the hospital and received another 6 mg of IV adenosine. The patient refused catheter ablation and was trialed on oral (PO) sotalol 80 mg twice daily in conjunction with PO metoprolol 50 mg twice daily. The patient was discharged without rhythm recurrence but presented again 3 days later due to recurrent AVNRT, treated with 6 mg IV adenosine, and admission to the hospital. Due to severe back pain during admission, an magnetic resonance imaging was obtained which showed C6–C7 diskitis/osteomyelitis and epidural abscess. Subsequent blood cultures were 2 out of 2 positive for methicillin-sensitive Staphylococcus aureus. Transthoracic echocardiogram was negative for vegetations, and blood cultures cleared with antibiotics. Transesophageal echocardiogram was not performed due to concern for cervical spine instability. Ablation was postponed due to active cervical infection. Due to a lack of control and episodes of bradycardia in the hospital sotalol was discontinued. The patient was then started on amiodarone 400 mg PO BID during the hospitalization. The patient was subsequently discharged with IV cefazolin, with outpatient cardiology and neurosurgery follow-up. The patient had no recurrence of the AVNRT while being followed on PO amiodarone, but eventually required C4-T1 fusion and decompression due to cervical spine instability and spinal cord compression. The patient refused ablation, was transiently lost to cardiology follow-up but will proceed at a future date.
Figure 1: Bulging neck veins are noted on the patient consistent with AVNRT “Frog sign”

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Figure 2: Electrocardiogram demonstrating a narrow complex tachycardia with retrograde “P” embedded in the QRS in V1, and retrograde “P” waves in II, II and AVF

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   Discussion Top

AVNRT is the most common SVT, consisting of a reentry circuit.[1] The circuitry involves the AV node and at least some part of the atrium.[1] The AV node is a complex structure with at least 1 fast pathway and 4 different slow pathways connecting it to the atrium [Figure 3] and [Figure 4].[3] The pathways are classified by their relative speed of conduction.
Figure 3: Left anterior oblique view-on top left anterior oblique view demonstrating the fast pathway and 3 possible slow pathways for typical AVNRT

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Figure 4: Right anterior oblique view-on top right anterior oblique view demonstrating the fast pathway and 3 possible slow pathways for typical AVNRT

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When anterograde conduction is blocked in the fast pathway with a premature atrial contraction, it goes down the slow pathway and comes back up the fast pathway to initiate AVNRT [Figure 5].[4],[5] There is atrial and ventricular stimulation which is almost simultaneous or in close succession. This results electrically in “P” and “QRS” in EKG in close proximity, and mechanically atria and ventricle contracting together with a closed tricuspid valve-giving rise to giant “a” waves in the jugular venous pulse.[4],[5] These giant “a” waves give us the “Frog Sign” in the neck.[4],[5]
Figure 5: Demonstration of AV nodal reentry in AVNRT

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Radiofrequency ablation of the reentry circuit is the gold standard for treatment[Video].

   Conclusion Top

“Frog Sign” is a classic physical exam finding that knowledge of aids in the diagnosis and management of patients presenting with typical AVNRT.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to not require Institutional Review Board/Ethics Committee review, and the corresponding protocol/approval number is not applicable.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Colucci RA, Silver MJ, Shubrook J. Common types of supraventricular tachycardia: Diagnosis and management. Am Fam Physician 2010;82:942-52.  Back to cited text no. 1
Katageri A, Gupta MD, Girish MP. Racing heart and pounding neck: Classic clinical sign revisited. Egypt Hear J 2016;68:135-6.  Back to cited text no. 2
Katritsis DG, Sepahpour A, Marine JE, Katritsis GD, Tanawuttiwat T, Calkins H, et al. Atypical atrioventricular nodal reentrant tachycardia: Prevalence, electrophysiologic characteristics, and tachycardia circuit. Europace 2015;17:1099-106.  Back to cited text no. 3
Velibey Y, Durak F, Türkkan C, Alper AT. “Frog Sign” in paroxysmal supraventricular tachycardia. Anatol J Cardiol 2018;19:E7.  Back to cited text no. 4
Contreras-Valdes FM, Josephson ME. Images in clinical medicine. “Frog Sign” in atrioventricular nodal reentrant tachycardia. N Engl J Med 2016;374:e17.  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]


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