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Persistent left superior vena cava: Multi-slice CT images and report of a case
International Journal of Cardiology 121 (2007) 112 – 114 www.elsevier.com/locate/ijcard
Letter to the Editor
Persistent left superior vena cava: Multi-slice CT images and report of a case Ching-Chang Fang a , Yeun Tarl Fresner Ng Jao a,⁎, Shu-Chen Han b , Shih-Pu Wang a a b
Cardiovascular Center, Tainan Municipal Hospital, Tainan, Taiwan Department of Radiology, Tainan Municipal Hospital, Tainan, Taiwan Received 23 July 2006; accepted 4 August 2006 Available online 28 November 2006
Abstract Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally during catheter placement or pacemaker implantation. Persistent left superior vena cava (PLSVC) is caused by failure of involution of the left anterior cardinal vein caudal to the left brachiocephalic vein during embryonic development. It is a benign condition, but becomes dangerous during pacemaker lead implantation, especially in emergency situations and when the right superior vena cava is absent. This is brought about by difficulty in pacemaker lead maneuvering into the right ventricle. A 64-cut multi-slice computed tomographic (MSCT) scan can show clear spatial relationship of the heart with its surrounding structures. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut MSCT scan. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Persistent left SVC; Pacemaker; Multi-slice CT scan
1. Introduction
2. Case report
The incidence of persistent left superior vena cava (PLSVC) is about 0.47%, while a solitary LSVC is 33% of those having the dual caval system [1]. It is the most common variation in the anomalous venous return to the heart and accounts for 0.2–4.3% of all congenital cardiac anomalies [2]. PLSVC is also associated with congenital cardiac anomalies like atrial and ventricular septal defects, sinus node dysfunction and electrical instability causing sudden death. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut multislice computed tomographic (MSCT) scan. To our knowledge, this is the first report of this anomaly, viewed using MSCT in the English literature.
An 80 year-old female was admitted due to lightheadedness. A year ago, she was admitted to our hospital due to dizziness. Holter ECG showed sinus bradycardia with no pause. One day prior, the patient while walking suddenly had light-headedness and fell to the ground without losing consciousness. ECG in the emergency department showed sinus pause with junctional escape rhythm. Pulse rate was 39/min and blood pressure was 137/65 mm Hg. Atropine was given and rate increased to 54/min. Past, personal, social histories, physical examination and laboratory data were unremarkable. Echocardiography was normal. Holter ECG showed sinus bradycardia ranging from 37 to 65 bpm with 2:1 2nd degree Mobitz type 2 atrioventricular block and sinus pauses of up to 1.9 s with junctional escape rhythm. Electrophysiologic study showed sinus nodal dysfunction with a corrected maximal sinus node reaction time of 940 ms and atrial pacing at 130 bpm elicited Wenckebach phenomenon. During pacemaker implantation via the left subclavian vein, the
⁎ Corresponding author. Cardiovascular Medicine, Critical Care Medicine, Tainan Municipal Hospital, Tainan 70120, Taiwan. Tel.: +886 6 2609926x3103; fax: +886 6 3312424. E-mail address: [email protected] (Y.T.F.N. Jao). 0167-5273/$ - see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2006.08.099
C.-C. Fang et al. / International Journal of Cardiology 121 (2007) 112–114
113
guidewire took an unusual route and descended on the left side in parallel with the aorta, entering the right atrium (RA) via the coronary sinus (CS) and exited the RA via the right SVC. After a lengthy procedural time, maneuvering the lead to the right ventricle (RV) failed. We abandoned the procedure and rescheduled it for a later time. A 64-cut MSCT scan showed calcifications over the aorta and coronary arteries. The right SVC drained into the RA anteriorly and superiorly, while the left SVC drained into the RA more inferiorly and posteriorly. A reconstructed image is shown (Figs. 1 and 2). After a few days, a permanent dual
Fig. 2. Three-dimensional reconstruction of both SVCs with the heart removed.
chamber pacemaker was successfully implanted via the right SVC route. Symptoms resolved and she is currently asymptomatic. 3. Discussion
Fig. 1. A. Three-dimensional reconstruction of the heart showing both caval systems (posterior caudal view). B. Three-dimensional reconstruction of the heart (posterior view).
The anterior and posterior cardinal veins drain cranial and caudal parts of the embryo respectively. In the 8th gestational week, the left brachiocephalic vein develops and connects the cranial portions of the two anterior cardinal veins (ACV). The caudal part of the right ACV becomes the normal right SVC, and the left ACV caudal to the left brachiocephalic vein degenerates and is marked by the oblique ligament and vein of Marshall. If this portion fails to involute, it forms a PLSVC [2]. Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally. ECG is not specific and chest radiograph may show a paramediastinal bulge below the aortic arch; a widened aortic shadow or a radiolucent strip or crescent shadow along the left upper cardiac border of the aortic arch toward the middle third of the left clavicle [3]. A transesophageal echocardiography is more sensitive and magnetic resonance imaging can show the entire course of the PLSVC. Though more sensitive than a CT scan, the diagnosis is usually confirmed by venography. The PLSVC usually empties into the CS. Passage of central catheters through the CS may cause supraventricular tachycardias in 38% of cases as opposed to the 7.9% via the right SVC [4]. Since the pacemaker electrode enters the RA through the CS in a left SVC route, the tip is directed away from the tricuspid valve, resulting in difficult maneuvering into the RV. Though different techniques were suggested,
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an epicardial route would be the only choice when all efforts fail. Though a report claimed that the left-sided approach did not increase fluoroscopic time compared to a right-sided approach [5], we still abandoned the procedure, since there was a patent right SVC, and no experience with the different maneuvers. Though successful long-term pacing has been reported via the PLSVC route, it is not without risk. Cardiologists who are not familiar with these techniques may risk complications in this relatively simple procedure. Therefore, if there is a patent right SVC, we suggest pacemaker lead implantation using the traditional way. Also, 64-cut MSCT is valuable in obtaining excellent anatomical spatial images of the heart and surrounding structures.
References [1] Biffi M, Boriani G, Frabetti L, Bronzetti G, Branzi A. Left superior vena cava persistence in patients undergoing pacemaker or cardioverterdefibrillator implantation. A 10-year experience. Chest 2001;120: 139–44. [2] Campbell M, Deuchar DC. The left sided superior vena cava. Br Heart J 1954;16:423–39. [3] Winters FS. Persistent left superior vena cava: survey of the world literature and report of thirty additional cases. Angiology 1954;5:90–132. [4] Fraser RS, Dvorkin J, Rossall RE, Eidem R. Left superior vena cava. A review of associated congenital heart lesions, catheterization data and roentgenologic findings. Am J Med 1961;31:711–6. [5] Lenox CC, Hashida Y, Anderson RH, Hubbard JD. Conduction tissue anomalies in absence of the right superior vena caval vein. Int J Cardiol 1985;8:251–60.
Letter to the Editor
Persistent left superior vena cava: Multi-slice CT images and report of a case Ching-Chang Fang a , Yeun Tarl Fresner Ng Jao a,⁎, Shu-Chen Han b , Shih-Pu Wang a a b
Cardiovascular Center, Tainan Municipal Hospital, Tainan, Taiwan Department of Radiology, Tainan Municipal Hospital, Tainan, Taiwan Received 23 July 2006; accepted 4 August 2006 Available online 28 November 2006
Abstract Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally during catheter placement or pacemaker implantation. Persistent left superior vena cava (PLSVC) is caused by failure of involution of the left anterior cardinal vein caudal to the left brachiocephalic vein during embryonic development. It is a benign condition, but becomes dangerous during pacemaker lead implantation, especially in emergency situations and when the right superior vena cava is absent. This is brought about by difficulty in pacemaker lead maneuvering into the right ventricle. A 64-cut multi-slice computed tomographic (MSCT) scan can show clear spatial relationship of the heart with its surrounding structures. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut MSCT scan. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Persistent left SVC; Pacemaker; Multi-slice CT scan
1. Introduction
2. Case report
The incidence of persistent left superior vena cava (PLSVC) is about 0.47%, while a solitary LSVC is 33% of those having the dual caval system [1]. It is the most common variation in the anomalous venous return to the heart and accounts for 0.2–4.3% of all congenital cardiac anomalies [2]. PLSVC is also associated with congenital cardiac anomalies like atrial and ventricular septal defects, sinus node dysfunction and electrical instability causing sudden death. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut multislice computed tomographic (MSCT) scan. To our knowledge, this is the first report of this anomaly, viewed using MSCT in the English literature.
An 80 year-old female was admitted due to lightheadedness. A year ago, she was admitted to our hospital due to dizziness. Holter ECG showed sinus bradycardia with no pause. One day prior, the patient while walking suddenly had light-headedness and fell to the ground without losing consciousness. ECG in the emergency department showed sinus pause with junctional escape rhythm. Pulse rate was 39/min and blood pressure was 137/65 mm Hg. Atropine was given and rate increased to 54/min. Past, personal, social histories, physical examination and laboratory data were unremarkable. Echocardiography was normal. Holter ECG showed sinus bradycardia ranging from 37 to 65 bpm with 2:1 2nd degree Mobitz type 2 atrioventricular block and sinus pauses of up to 1.9 s with junctional escape rhythm. Electrophysiologic study showed sinus nodal dysfunction with a corrected maximal sinus node reaction time of 940 ms and atrial pacing at 130 bpm elicited Wenckebach phenomenon. During pacemaker implantation via the left subclavian vein, the
⁎ Corresponding author. Cardiovascular Medicine, Critical Care Medicine, Tainan Municipal Hospital, Tainan 70120, Taiwan. Tel.: +886 6 2609926x3103; fax: +886 6 3312424. E-mail address: [email protected] (Y.T.F.N. Jao). 0167-5273/$ - see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2006.08.099
C.-C. Fang et al. / International Journal of Cardiology 121 (2007) 112–114
113
guidewire took an unusual route and descended on the left side in parallel with the aorta, entering the right atrium (RA) via the coronary sinus (CS) and exited the RA via the right SVC. After a lengthy procedural time, maneuvering the lead to the right ventricle (RV) failed. We abandoned the procedure and rescheduled it for a later time. A 64-cut MSCT scan showed calcifications over the aorta and coronary arteries. The right SVC drained into the RA anteriorly and superiorly, while the left SVC drained into the RA more inferiorly and posteriorly. A reconstructed image is shown (Figs. 1 and 2). After a few days, a permanent dual
Fig. 2. Three-dimensional reconstruction of both SVCs with the heart removed.
chamber pacemaker was successfully implanted via the right SVC route. Symptoms resolved and she is currently asymptomatic. 3. Discussion
Fig. 1. A. Three-dimensional reconstruction of the heart showing both caval systems (posterior caudal view). B. Three-dimensional reconstruction of the heart (posterior view).
The anterior and posterior cardinal veins drain cranial and caudal parts of the embryo respectively. In the 8th gestational week, the left brachiocephalic vein develops and connects the cranial portions of the two anterior cardinal veins (ACV). The caudal part of the right ACV becomes the normal right SVC, and the left ACV caudal to the left brachiocephalic vein degenerates and is marked by the oblique ligament and vein of Marshall. If this portion fails to involute, it forms a PLSVC [2]. Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally. ECG is not specific and chest radiograph may show a paramediastinal bulge below the aortic arch; a widened aortic shadow or a radiolucent strip or crescent shadow along the left upper cardiac border of the aortic arch toward the middle third of the left clavicle [3]. A transesophageal echocardiography is more sensitive and magnetic resonance imaging can show the entire course of the PLSVC. Though more sensitive than a CT scan, the diagnosis is usually confirmed by venography. The PLSVC usually empties into the CS. Passage of central catheters through the CS may cause supraventricular tachycardias in 38% of cases as opposed to the 7.9% via the right SVC [4]. Since the pacemaker electrode enters the RA through the CS in a left SVC route, the tip is directed away from the tricuspid valve, resulting in difficult maneuvering into the RV. Though different techniques were suggested,
114
C.-C. Fang et al. / International Journal of Cardiology 121 (2007) 112–114
an epicardial route would be the only choice when all efforts fail. Though a report claimed that the left-sided approach did not increase fluoroscopic time compared to a right-sided approach [5], we still abandoned the procedure, since there was a patent right SVC, and no experience with the different maneuvers. Though successful long-term pacing has been reported via the PLSVC route, it is not without risk. Cardiologists who are not familiar with these techniques may risk complications in this relatively simple procedure. Therefore, if there is a patent right SVC, we suggest pacemaker lead implantation using the traditional way. Also, 64-cut MSCT is valuable in obtaining excellent anatomical spatial images of the heart and surrounding structures.
References [1] Biffi M, Boriani G, Frabetti L, Bronzetti G, Branzi A. Left superior vena cava persistence in patients undergoing pacemaker or cardioverterdefibrillator implantation. A 10-year experience. Chest 2001;120: 139–44. [2] Campbell M, Deuchar DC. The left sided superior vena cava. Br Heart J 1954;16:423–39. [3] Winters FS. Persistent left superior vena cava: survey of the world literature and report of thirty additional cases. Angiology 1954;5:90–132. [4] Fraser RS, Dvorkin J, Rossall RE, Eidem R. Left superior vena cava. A review of associated congenital heart lesions, catheterization data and roentgenologic findings. Am J Med 1961;31:711–6. [5] Lenox CC, Hashida Y, Anderson RH, Hubbard JD. Conduction tissue anomalies in absence of the right superior vena caval vein. Int J Cardiol 1985;8:251–60.