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Syncope due to unexpected paroxysmal sinus arrest
Journal of Electrocardiology 58 (2020) 61–62
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Journal of Electrocardiology journal homepage: www.jecgonline.com
Syncope due to unexpected paroxysmal sinus arrest János Tomcsányi, MD a,⁎, Béla Bózsik, MD a, Hein J. Wellens, MD b a b
Cardiology Department, St. John of God Hospital, Budapest, Hungary Cardiovascular Research Institute, Maastricht, the Netherlands
a r t i c l e
i n f o
Available online xxxx Keywords: Syncope Sick sinus syndrome Implantable loop recorder Atrial pacemaker
a b s t r a c t We present two cases with unexpected long sinus arrest resulting in syncope. There were no signs or symptoms of either sick sinus syndrome or increased vagal tone before the occurrence of pauses in these patients. The fact that these patients remained asymptomatic for quite long shows striking resemblance to paroxysmal sub-AV nodal block. We would therefore prefer to classify these cases as paroxysmal sinus arrest as a possible manifestation of the sick sinus syndrome. © 2018 Elsevier Inc. All rights reserved.
Introduction
Case presentation 2
Sick sinus syndrome is one of the arrhythmogenic causes of syncope either through the failure of impulse formation in the sinus node or as a result of a block between the sinus node and the atrium. Typically, a long sinus pause causing syncope is preceded by progressive sinus bradycardia leading to sinus arrest [1,2]. We present two unusual cases of syncope without any preceding sinus cycle length changes.
A 49 year old man was referred to our outpatient clinic by his general practitioner because of two episodes of syncope during the past two months. Two 12 lead ECGs made by the general practitioner were normal. However, when his ECG was recorded after arrival in the outpatient clinic he showed during a sinus rhythm of 100 beats/min all of a sudden complete sinus arrest (Fig. 2) telling us that this was one of the episodes he suffered from. Normal sinus rhythm, rate 85 beats/min, with normal PR and similar QRS-T complex resumed after 12 s.
Case presentation 1 Discussion A 54-year-old male had had three sudden episodes of syncope over the course of three years. The first syncope resulted in a subdural hematoma and permanent hearing loss, whereas the second one, one year later caused a fracture of the iliac bone. The third syncopal episode did not result in traumatic injuries. Extensive cardiological and neurological investigations carried out after the syncope could not identify the cause of these episodes. All electrocardiograms recorded outside the syncopal attack showed normal sinus rhythm with normal PR and normal QRS-T complex. After the third syncope the patient was referred for the implantation of an implantable loop recorder (ILR). Eight months after the implantation the patient had a morning episode of dizziness with a corresponding RR pause of 7 s during an episode of sinus arrest lasting for 31.6 s (Fig. 1).
⁎ Corresponding author at: St. John of God Hospital, Cardiology Department, 1027 Árpád fejedelem u.7., Budapest, Hungary. E-mail address: [email protected] (J. Tomcsányi).
https://doi.org/10.1016/j.jelectrocard.2019.11.048 0022-0736/© 2018 Elsevier Inc. All rights reserved.
These two cases show a sudden sinus arrest without preceding sinus rate changes or P-QRS-T abnormalities. Neither of these patients had abnormalities on extensive cardiac examination. The paroxysmal, unexpected and recurring nature of these episodes reminds us of some of features of paroxysmal atrioventricular sub-AV nodal block [3]. However that mechanism requires a rate change to create sub-AV nodal phase-4 block. But, apart from the unexpected paroxysmal behavior, patient 2 showed a perfectly regular P-P interval for several beats before the arrest and patient 1 showed only a slight lengthening of the P-P interval before the pause. This would make a sudden unexplained vagal reaction highly unlikely, and also the fact that the PR intervals before and after the syncope were normal. We have no basic electrophysiologic explanation for our observation in these two cases, whether it is the absence of impulse formation in the sinus node or complete sino-atrial block. We would therefore prefer to use the term paroxysmal sinus arrest. We are not aware of any other publications describing similar cases with the findings described above. They can be included in the different possible manifestations of the sick sinus syndrome. Both patients received an AAI pacemaker.
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J. Tomcsányi et al. / Journal of Electrocardiology 58 (2020) 61–62
Fig. 1. Real time registration 8 months after implant of a loop recorder showing an initially stable sinus rate followed by a sudden pause of 7 s. Thereafter, junctional escape beats occur with sinus arrest lasting for 31.6 s followed by normal sinus rhythm.
Fig. 2. Six simultaneously recorded ECG leads showing regular sinus rhythm, with sudden sinus arrest followed by two junctional escape beats. Normal sinus rhythm resumed after 12 s (not shown).
References [1] Brignole M, Moya A, Menozzi C, et al. Proposed electrocardiographic classification of spontaneous syncope documented by an implantable loop recorder. Europace 2005; 7:14–8.
[2] Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018;39(21):1883–948. [3] Lee S, Wellens HJ, Josephson M. Paroxysmal atrioventricular block. Heart Rhythm 2009;6:1229–34.
Contents lists available at ScienceDirect
Journal of Electrocardiology journal homepage: www.jecgonline.com
Syncope due to unexpected paroxysmal sinus arrest János Tomcsányi, MD a,⁎, Béla Bózsik, MD a, Hein J. Wellens, MD b a b
Cardiology Department, St. John of God Hospital, Budapest, Hungary Cardiovascular Research Institute, Maastricht, the Netherlands
a r t i c l e
i n f o
Available online xxxx Keywords: Syncope Sick sinus syndrome Implantable loop recorder Atrial pacemaker
a b s t r a c t We present two cases with unexpected long sinus arrest resulting in syncope. There were no signs or symptoms of either sick sinus syndrome or increased vagal tone before the occurrence of pauses in these patients. The fact that these patients remained asymptomatic for quite long shows striking resemblance to paroxysmal sub-AV nodal block. We would therefore prefer to classify these cases as paroxysmal sinus arrest as a possible manifestation of the sick sinus syndrome. © 2018 Elsevier Inc. All rights reserved.
Introduction
Case presentation 2
Sick sinus syndrome is one of the arrhythmogenic causes of syncope either through the failure of impulse formation in the sinus node or as a result of a block between the sinus node and the atrium. Typically, a long sinus pause causing syncope is preceded by progressive sinus bradycardia leading to sinus arrest [1,2]. We present two unusual cases of syncope without any preceding sinus cycle length changes.
A 49 year old man was referred to our outpatient clinic by his general practitioner because of two episodes of syncope during the past two months. Two 12 lead ECGs made by the general practitioner were normal. However, when his ECG was recorded after arrival in the outpatient clinic he showed during a sinus rhythm of 100 beats/min all of a sudden complete sinus arrest (Fig. 2) telling us that this was one of the episodes he suffered from. Normal sinus rhythm, rate 85 beats/min, with normal PR and similar QRS-T complex resumed after 12 s.
Case presentation 1 Discussion A 54-year-old male had had three sudden episodes of syncope over the course of three years. The first syncope resulted in a subdural hematoma and permanent hearing loss, whereas the second one, one year later caused a fracture of the iliac bone. The third syncopal episode did not result in traumatic injuries. Extensive cardiological and neurological investigations carried out after the syncope could not identify the cause of these episodes. All electrocardiograms recorded outside the syncopal attack showed normal sinus rhythm with normal PR and normal QRS-T complex. After the third syncope the patient was referred for the implantation of an implantable loop recorder (ILR). Eight months after the implantation the patient had a morning episode of dizziness with a corresponding RR pause of 7 s during an episode of sinus arrest lasting for 31.6 s (Fig. 1).
⁎ Corresponding author at: St. John of God Hospital, Cardiology Department, 1027 Árpád fejedelem u.7., Budapest, Hungary. E-mail address: [email protected] (J. Tomcsányi).
https://doi.org/10.1016/j.jelectrocard.2019.11.048 0022-0736/© 2018 Elsevier Inc. All rights reserved.
These two cases show a sudden sinus arrest without preceding sinus rate changes or P-QRS-T abnormalities. Neither of these patients had abnormalities on extensive cardiac examination. The paroxysmal, unexpected and recurring nature of these episodes reminds us of some of features of paroxysmal atrioventricular sub-AV nodal block [3]. However that mechanism requires a rate change to create sub-AV nodal phase-4 block. But, apart from the unexpected paroxysmal behavior, patient 2 showed a perfectly regular P-P interval for several beats before the arrest and patient 1 showed only a slight lengthening of the P-P interval before the pause. This would make a sudden unexplained vagal reaction highly unlikely, and also the fact that the PR intervals before and after the syncope were normal. We have no basic electrophysiologic explanation for our observation in these two cases, whether it is the absence of impulse formation in the sinus node or complete sino-atrial block. We would therefore prefer to use the term paroxysmal sinus arrest. We are not aware of any other publications describing similar cases with the findings described above. They can be included in the different possible manifestations of the sick sinus syndrome. Both patients received an AAI pacemaker.
62
J. Tomcsányi et al. / Journal of Electrocardiology 58 (2020) 61–62
Fig. 1. Real time registration 8 months after implant of a loop recorder showing an initially stable sinus rate followed by a sudden pause of 7 s. Thereafter, junctional escape beats occur with sinus arrest lasting for 31.6 s followed by normal sinus rhythm.
Fig. 2. Six simultaneously recorded ECG leads showing regular sinus rhythm, with sudden sinus arrest followed by two junctional escape beats. Normal sinus rhythm resumed after 12 s (not shown).
References [1] Brignole M, Moya A, Menozzi C, et al. Proposed electrocardiographic classification of spontaneous syncope documented by an implantable loop recorder. Europace 2005; 7:14–8.
[2] Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018;39(21):1883–948. [3] Lee S, Wellens HJ, Josephson M. Paroxysmal atrioventricular block. Heart Rhythm 2009;6:1229–34.