Acta Cardiologica
ISSN: 0001-5385 (Print) 0373-7934 (Online) Journal homepage: http://www.tandfonline.com/loi/tacd20
Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery Bekir Serhat Yildiz, Yusuf Izzettin Alihanoglu, Ismail Dogu Kilic & Harun Evrengul To cite this article: Bekir Serhat Yildiz, Yusuf Izzettin Alihanoglu, Ismail Dogu Kilic & Harun Evrengul (2014) Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery, Acta Cardiologica, 69:3, 334-337, DOI: 10.1080/AC.69.3.3027844 To link to this article: https://doi.org/10.1080/AC.69.3.3027844
Published online: 23 May 2017.
Submit your article to this journal
Article views: 2
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tacd20
334
Acta Cardiol 2014; 69(3): 334-337
doi: 10.2143/AC.69.3.3027844
Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery Bekir Serhat YILDIZ, MD; Yusuf Izzettin ALIHANOGLU, MD; Ismail Dogu KILIC, MD; Harun EVRENGUL Pamukkale University, Medical Faculty, Dept. of Cardiology, Denizli, Turkey.
Abstract Radiofrequency (RF) ablation of accessory bypass tracts associated with the Wolff-Parkinson-White (WPW) syndrome has become the treatment of choice for many arrhythmias. Complications are unusual and acute coronary artery occlusion is very rare. We here present a 38-year-old male patient with an acute occlusion of proximal left anterior descending (LAD) coronary artery after RF ablation of a left free wall accessory pathway. An interesting feature is the site of the coronary artery occlusion which is remote from the RF application site. The occlusion was successfully treated with the placement of an intracoronary stent.
Keywords Radiofrequency catheter ablation – accessory pathway – angioplasty – stent.
INTRODUCTION
CASE REPORT
Radiofrequency (RF) ablation of accessory bypass tracts associated with the Wolff-Parkinson-White (WPW) syndrome has become the treatment of choice for many arrhythmias. The success rates of catheter ablation of various types of cardiac arrhythmias are impressively high. Procedure-related complications can be dependent on the invasive nature of the technique but may also occur as a specific complication related to the type of intervention performed. Coronary artery occlusion as a complication of an RF catheter ablation in particular, is exceedingly uncommon1.
A 38-year-old man was admitted to the cardiology out-patient clinic with one episode of near-syncope preceded by palpitations. The electrocardiogram (ECG) showed sinus rhythm with manifest delta wave in all ECG derivations and pre-excitation in inferior ECG derivations (figure 1). The patient had no history or documentation of previous supraventricular tachycardia (SVT). The clinical examination was unremarkable and the patient had no coronary risk factors except smoking and hyperlipidaemia. Transthoracic echocardiography was normal. The patient was taken to the electrophysiology laboratory after 8 hours fasting. The Hisventricular (HV) interval was 5 ms. Programmed atrial stimulation induced antidromic tachycardia. During antidromic AVRT, there was antegrade conduction over the accessory pathway with the earliest atrial activation in the left lateral atrial site. After intravenous administration of 5,000 IU of heparin, mapping in the left anterolateral region was performed via a retrograde aortic approach. Under fluoroscopic guidance, a 7-F ablation catheter with a deflectable tip was advanced across the aortic valve without difficulty (figure 2 A-B). Left side mapping was performed in 15 minutes. After five
Address for correspondence: Bekir Serhat YILDIZ, MD, Pamukkale University, Medical Faculty, Dept. of Cardiology, 20100 Denizli, Turkey E-mail: [email protected] Received 26 November 2013; revision accepted for publication 19 February 2014.
Left lateral free wall pathway ablation
Fig. 1 Sinus rhythm with manifest delta wave in all ECG derivations and pre-excitation in inferior ECG derivations.
Fig. 2 A-B: retrograde aortic approach in electrophysiologic mapping; C: arrow shows total occlusion of the proximal left anterior descending (LAD) artery, D: TIMI 3 flow was achieved after thrombectomy and stent implantation.
applications of RF energy, the accessory pathway was successfully ablated, and the tachycardia was no longer inducible. Ventriculo-atrial block was observed. During the ablation procedure, power was set at 35 W and the maximal achieved temperature was 60°C. The catheter was promptly removed from the coronary arterial circulation during mapping and ablation. There was no procedure-related complication. The ECG was normal without delta waves after the procedure. No additional heparin was administered. 100 mg aspirin was given to the patient. Five minutes after the procedure the patient complained of a new onset of chest pain. The ECG demonstrated ST-segment elevation in anterior and lateral derivations with sinus rhythm. Intravenous nitroglycerin was initiated to rule out spasm. No change in ECG was observed after nitroglycerin infusion. The patient was admitted to the catheterization laboratory with the diagnosis of an acute coronary syndrome.
Coronary angiography demonstrated total occlusion of the proximal left anterior descending (LAD) artery (figure 2 C). The circumflex (Cx) artery and right coronary artery were normal. The left main coronary artery (LMCA) was entered with a 7-F JL4 coronary guiding catheter. The lesion was crossed with an 0.014-inch coronary guide wire. A thrombectomy catheter was advanced over the wire. After aspiration along the proximal LAD antegrade flow was restored. A 4 × 3 × 2-mm soft tissue specimen and white material was extracted via the aspiration catheter (figure 3). A 3.5 × 15-mm stent was implanted and restored TIMI 3 flow (figure 2 D). Chest pain decreased and ST-segment elevation was resolved. Pathological evaluation of the tissue specimen revealed a cluster of inflammatory cells and fibrinous material. The patient was discharged the next day on clopidogrel 75 mg per day for 1 year; aspirin 300 mg for one month; and 100 mg afterwards.
335
336
B.S. Yildiz et al.
Fig. 3
Arrow shows tissue specimen after thrombectomy.
DISCUSSION RFA has proved to be very effective in removing accessory atrioventricular pathways with high success and has a relatively low complication rate. These complications include: femoral access sites, atrioventricular block, bleeding and cardiac rupture. Coronary complications in particular are quite uncommon1. Strickberger et al.2 prospectively monitored 16 patients whose coronary arteries were normal before RF ablation. Repeat coronary angiography 3 to 11 months later showed no abnormalities. Solomon et al.3 performed quantitative coronary angiography of 70 patients before, immediately after, 1 to 3 months after RF ablation. Only one patient demonstrated reduction in vessel calibre immediately after RF ablation due to acute coronary spasm with distal occlusion. It was reversed with medical therapy without subsequent myocardial infarction. Calkins et al.4, reporting on 106 patients, described one case of inadvertent RF energy delivery in the Cx coronary artery resulting in myocardial infarction. Kosinski et al.5 described a 17-year-old male in whom ventricular tachycardia (VT) and ST-segment elevation occurred after RF ablation for a left-sided accessory pathway. Coronary angiography showed complete occlusion of the LMCA. In spite of emergency angioplasty and subsequent bypass surgery, the patient ultimately died. Hope et al.6 reported a second case of LMCA occlusion 12 h after RF ablation for an accessory pathway in a 40-year-old woman. Dinckal et al.7 reported LAD coronary artery occlusion after left lateral free wall accessory pathway ablation with frequent episodes of supraventricular tachycardia (SVT), which was resistant to antiarrhythmics in a 32-year-old male. Unlike the other cases Turkoglu et al.8 reported
chronic total occlusion of Cx artery after radiofrequency ablation of a left ventricular tract tachycardia in a 22-year-old woman. After the beginning of RF ablation, thermal damage from RF energy has been implicated as a cause of complication of RF ablation therapy2-3. Coronary artery damage is most likely to occur during ablation on the atrial side of the valve annuli and within the coronary sinus. Transmural lesions with involvement of epicardial coronary arteries are also possible during catheter ablation within the ventricle as in Dinckals’ case7. In our patient we used the retrograde aortic approach, since the ablation site was far from the LAD and indirect trauma to the LAD was not possible. Coronary spasm is another explanation for coronary injury subsequent to RF ablation. Spasm is postulated to be the most common cause particularly if the RF energy is delivered within the coronary sinus because of its proximity to the epicardial surface of the heart. Inadvertent delivery of intracoronary RF current can result in serious coronary complications with acute or subacute occlusion. But RF energy was not given through the coronary sinus. Alternatively, a coronary artery could be directly traumatized by the ablation catheter during attempts to cross the aortic valve with subsequent intimal dissection and thrombus formation. This hypothesis is considered to be the most logical explanation for LMCA occlusion in contrast to our patient only with proximal LAD occlusion. We assumed that acute occlusion of the proximal LAD was caused by dissection of vulnerable atherosclerotic plaque with indirect thermal trauma although it is far from the RF application site. Due to the RF application site (left lateral atrioventricular groove) indirect thermal trauma (oedema and intimal injury within the vessel wall) would be expected to affect the Cx artery, but the vessel occlusion was detected in the proximal LAD and the obstruction site is far from the target site. The soft tissue specimen that was extracted from the thrombectomy catheter was reported as a cluster of inflammatory cells and fibrinous material. This indicates the rupture or dissection of a vulnerable plaque in the proximal LAD. Before the RF ablation procedure the patient had no anginal symptoms. As a consequence, he did not undergo coronary angiography before the RF ablation procedure and the vulnerable atherosclerotic plaque went unnoticed. Our case illustrates an unusual complication of RF ablation and reinforces the importance of careful catheter manipulation and appropriate antithrombotic measures for patients undergoing left-sided electrophysiologic study or RF ablation. Despite systemic anticoagulation and care in prolapsing the ablation catheter across the aortic valve, this complication still can occur. We administer 300 mg aspirin for 3 months
Left lateral free wall pathway ablation
after any ablation procedure involving a left side approach. Although the overall risk of coronary artery complications with RF ablation is low, this case reinforces the importance of RF application to be performed carefully, in particular when the target site is on the left atrial site. Therefore, we recommend that all patients
undergoing an ablation procedure involving entry into the left ventricle should be monitored overnight after the procedure. Full anticoagulation should be taken during left-sided procedures and the operator should be careful in the manipulation of catheters and titration of RF energy.
REFERENCES 1. Hindricks G, for the MERFS investigators. The Multicentre European Radiofrequency Survey (MERFS): complications of radiofrequency ablation of arrhythmias. The Multicentre European Radiofrequency Survey (MERFS) investigators of the Working Group on Arrhythmias of the European Society of Cardiology. Eur Heart J 1993; 14: 1644-53. 2. Strickberger SA, Okishige K, Meyerovitz S, Shea J, Friedman PL. Evaluation of possible long-term adverse consequences of radiofrequency catheter ablation of accessory pathways. Am J Cardiol 1993; 71: 473-5. 3. Soloman AJ, Tracy CM, Swartz JF, Reagan KM, Karasik PE, Fletcher RD. Effect on coronary
artery anatomy of radiofrequency catheter ablation of atrial insertion sites of accessory pathways. J Am Coll Cardiol 1993; 21: 1440-4. 4. Calkins H, Sousa J, el-Atassi R, Rosenheck S, de Buitleir M, Kou WH, Kadish AH, Langberg JJ, Morady F. Diagnosis and cure of Wolff–Parkinson–White Syndrome or paroxysmal supraventricular tachycardia during a single electrophysiologic test. N Engl J Med 1991; 324: 1612-8. 5. Kosinski DJ, Burket MW, Durzinsky D. Occlusion of the left main coronary artery during radiofrequency ablation for the Wolff– Parkinson–White syndrome. Eur J Card Pacing Electrophysiol 1993; 3: 63-6.
6. Hope EJ, Haigney MC, Calkins H, Resar JR. Left main coronary thrombosis after radiofrequency ablation: successful treatment with percutaneous transluminal angioplasty. Am Heart J 1995; 129: 1217-9. 7. Dinckal H, Yucel O, Kirilmaz A, Karaca M, Kilicaslan F, Dokumaci B. Left anterior descending coronary artery occlusion after left lateral free wall accessory pathway ablation: what is the possible mechanism? Europace 2003; 5: 263-6. 8. Turkoğlu C, Aliyev F, Arat-Ozkan A, Gürmen T. Chronic total occlusion of left circumflex artery after radiofrequency ablation of left ventricular outflow tract tachycardia. Europace 2010; 12: 443-4.
337
ISSN: 0001-5385 (Print) 0373-7934 (Online) Journal homepage: http://www.tandfonline.com/loi/tacd20
Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery Bekir Serhat Yildiz, Yusuf Izzettin Alihanoglu, Ismail Dogu Kilic & Harun Evrengul To cite this article: Bekir Serhat Yildiz, Yusuf Izzettin Alihanoglu, Ismail Dogu Kilic & Harun Evrengul (2014) Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery, Acta Cardiologica, 69:3, 334-337, DOI: 10.1080/AC.69.3.3027844 To link to this article: https://doi.org/10.1080/AC.69.3.3027844
Published online: 23 May 2017.
Submit your article to this journal
Article views: 2
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tacd20
334
Acta Cardiol 2014; 69(3): 334-337
doi: 10.2143/AC.69.3.3027844
Left lateral free wall pathway ablation complicated by plaque rupture and acute occlusion of the left anterior descending coronary artery Bekir Serhat YILDIZ, MD; Yusuf Izzettin ALIHANOGLU, MD; Ismail Dogu KILIC, MD; Harun EVRENGUL Pamukkale University, Medical Faculty, Dept. of Cardiology, Denizli, Turkey.
Abstract Radiofrequency (RF) ablation of accessory bypass tracts associated with the Wolff-Parkinson-White (WPW) syndrome has become the treatment of choice for many arrhythmias. Complications are unusual and acute coronary artery occlusion is very rare. We here present a 38-year-old male patient with an acute occlusion of proximal left anterior descending (LAD) coronary artery after RF ablation of a left free wall accessory pathway. An interesting feature is the site of the coronary artery occlusion which is remote from the RF application site. The occlusion was successfully treated with the placement of an intracoronary stent.
Keywords Radiofrequency catheter ablation – accessory pathway – angioplasty – stent.
INTRODUCTION
CASE REPORT
Radiofrequency (RF) ablation of accessory bypass tracts associated with the Wolff-Parkinson-White (WPW) syndrome has become the treatment of choice for many arrhythmias. The success rates of catheter ablation of various types of cardiac arrhythmias are impressively high. Procedure-related complications can be dependent on the invasive nature of the technique but may also occur as a specific complication related to the type of intervention performed. Coronary artery occlusion as a complication of an RF catheter ablation in particular, is exceedingly uncommon1.
A 38-year-old man was admitted to the cardiology out-patient clinic with one episode of near-syncope preceded by palpitations. The electrocardiogram (ECG) showed sinus rhythm with manifest delta wave in all ECG derivations and pre-excitation in inferior ECG derivations (figure 1). The patient had no history or documentation of previous supraventricular tachycardia (SVT). The clinical examination was unremarkable and the patient had no coronary risk factors except smoking and hyperlipidaemia. Transthoracic echocardiography was normal. The patient was taken to the electrophysiology laboratory after 8 hours fasting. The Hisventricular (HV) interval was 5 ms. Programmed atrial stimulation induced antidromic tachycardia. During antidromic AVRT, there was antegrade conduction over the accessory pathway with the earliest atrial activation in the left lateral atrial site. After intravenous administration of 5,000 IU of heparin, mapping in the left anterolateral region was performed via a retrograde aortic approach. Under fluoroscopic guidance, a 7-F ablation catheter with a deflectable tip was advanced across the aortic valve without difficulty (figure 2 A-B). Left side mapping was performed in 15 minutes. After five
Address for correspondence: Bekir Serhat YILDIZ, MD, Pamukkale University, Medical Faculty, Dept. of Cardiology, 20100 Denizli, Turkey E-mail: [email protected] Received 26 November 2013; revision accepted for publication 19 February 2014.
Left lateral free wall pathway ablation
Fig. 1 Sinus rhythm with manifest delta wave in all ECG derivations and pre-excitation in inferior ECG derivations.
Fig. 2 A-B: retrograde aortic approach in electrophysiologic mapping; C: arrow shows total occlusion of the proximal left anterior descending (LAD) artery, D: TIMI 3 flow was achieved after thrombectomy and stent implantation.
applications of RF energy, the accessory pathway was successfully ablated, and the tachycardia was no longer inducible. Ventriculo-atrial block was observed. During the ablation procedure, power was set at 35 W and the maximal achieved temperature was 60°C. The catheter was promptly removed from the coronary arterial circulation during mapping and ablation. There was no procedure-related complication. The ECG was normal without delta waves after the procedure. No additional heparin was administered. 100 mg aspirin was given to the patient. Five minutes after the procedure the patient complained of a new onset of chest pain. The ECG demonstrated ST-segment elevation in anterior and lateral derivations with sinus rhythm. Intravenous nitroglycerin was initiated to rule out spasm. No change in ECG was observed after nitroglycerin infusion. The patient was admitted to the catheterization laboratory with the diagnosis of an acute coronary syndrome.
Coronary angiography demonstrated total occlusion of the proximal left anterior descending (LAD) artery (figure 2 C). The circumflex (Cx) artery and right coronary artery were normal. The left main coronary artery (LMCA) was entered with a 7-F JL4 coronary guiding catheter. The lesion was crossed with an 0.014-inch coronary guide wire. A thrombectomy catheter was advanced over the wire. After aspiration along the proximal LAD antegrade flow was restored. A 4 × 3 × 2-mm soft tissue specimen and white material was extracted via the aspiration catheter (figure 3). A 3.5 × 15-mm stent was implanted and restored TIMI 3 flow (figure 2 D). Chest pain decreased and ST-segment elevation was resolved. Pathological evaluation of the tissue specimen revealed a cluster of inflammatory cells and fibrinous material. The patient was discharged the next day on clopidogrel 75 mg per day for 1 year; aspirin 300 mg for one month; and 100 mg afterwards.
335
336
B.S. Yildiz et al.
Fig. 3
Arrow shows tissue specimen after thrombectomy.
DISCUSSION RFA has proved to be very effective in removing accessory atrioventricular pathways with high success and has a relatively low complication rate. These complications include: femoral access sites, atrioventricular block, bleeding and cardiac rupture. Coronary complications in particular are quite uncommon1. Strickberger et al.2 prospectively monitored 16 patients whose coronary arteries were normal before RF ablation. Repeat coronary angiography 3 to 11 months later showed no abnormalities. Solomon et al.3 performed quantitative coronary angiography of 70 patients before, immediately after, 1 to 3 months after RF ablation. Only one patient demonstrated reduction in vessel calibre immediately after RF ablation due to acute coronary spasm with distal occlusion. It was reversed with medical therapy without subsequent myocardial infarction. Calkins et al.4, reporting on 106 patients, described one case of inadvertent RF energy delivery in the Cx coronary artery resulting in myocardial infarction. Kosinski et al.5 described a 17-year-old male in whom ventricular tachycardia (VT) and ST-segment elevation occurred after RF ablation for a left-sided accessory pathway. Coronary angiography showed complete occlusion of the LMCA. In spite of emergency angioplasty and subsequent bypass surgery, the patient ultimately died. Hope et al.6 reported a second case of LMCA occlusion 12 h after RF ablation for an accessory pathway in a 40-year-old woman. Dinckal et al.7 reported LAD coronary artery occlusion after left lateral free wall accessory pathway ablation with frequent episodes of supraventricular tachycardia (SVT), which was resistant to antiarrhythmics in a 32-year-old male. Unlike the other cases Turkoglu et al.8 reported
chronic total occlusion of Cx artery after radiofrequency ablation of a left ventricular tract tachycardia in a 22-year-old woman. After the beginning of RF ablation, thermal damage from RF energy has been implicated as a cause of complication of RF ablation therapy2-3. Coronary artery damage is most likely to occur during ablation on the atrial side of the valve annuli and within the coronary sinus. Transmural lesions with involvement of epicardial coronary arteries are also possible during catheter ablation within the ventricle as in Dinckals’ case7. In our patient we used the retrograde aortic approach, since the ablation site was far from the LAD and indirect trauma to the LAD was not possible. Coronary spasm is another explanation for coronary injury subsequent to RF ablation. Spasm is postulated to be the most common cause particularly if the RF energy is delivered within the coronary sinus because of its proximity to the epicardial surface of the heart. Inadvertent delivery of intracoronary RF current can result in serious coronary complications with acute or subacute occlusion. But RF energy was not given through the coronary sinus. Alternatively, a coronary artery could be directly traumatized by the ablation catheter during attempts to cross the aortic valve with subsequent intimal dissection and thrombus formation. This hypothesis is considered to be the most logical explanation for LMCA occlusion in contrast to our patient only with proximal LAD occlusion. We assumed that acute occlusion of the proximal LAD was caused by dissection of vulnerable atherosclerotic plaque with indirect thermal trauma although it is far from the RF application site. Due to the RF application site (left lateral atrioventricular groove) indirect thermal trauma (oedema and intimal injury within the vessel wall) would be expected to affect the Cx artery, but the vessel occlusion was detected in the proximal LAD and the obstruction site is far from the target site. The soft tissue specimen that was extracted from the thrombectomy catheter was reported as a cluster of inflammatory cells and fibrinous material. This indicates the rupture or dissection of a vulnerable plaque in the proximal LAD. Before the RF ablation procedure the patient had no anginal symptoms. As a consequence, he did not undergo coronary angiography before the RF ablation procedure and the vulnerable atherosclerotic plaque went unnoticed. Our case illustrates an unusual complication of RF ablation and reinforces the importance of careful catheter manipulation and appropriate antithrombotic measures for patients undergoing left-sided electrophysiologic study or RF ablation. Despite systemic anticoagulation and care in prolapsing the ablation catheter across the aortic valve, this complication still can occur. We administer 300 mg aspirin for 3 months
Left lateral free wall pathway ablation
after any ablation procedure involving a left side approach. Although the overall risk of coronary artery complications with RF ablation is low, this case reinforces the importance of RF application to be performed carefully, in particular when the target site is on the left atrial site. Therefore, we recommend that all patients
undergoing an ablation procedure involving entry into the left ventricle should be monitored overnight after the procedure. Full anticoagulation should be taken during left-sided procedures and the operator should be careful in the manipulation of catheters and titration of RF energy.
REFERENCES 1. Hindricks G, for the MERFS investigators. The Multicentre European Radiofrequency Survey (MERFS): complications of radiofrequency ablation of arrhythmias. The Multicentre European Radiofrequency Survey (MERFS) investigators of the Working Group on Arrhythmias of the European Society of Cardiology. Eur Heart J 1993; 14: 1644-53. 2. Strickberger SA, Okishige K, Meyerovitz S, Shea J, Friedman PL. Evaluation of possible long-term adverse consequences of radiofrequency catheter ablation of accessory pathways. Am J Cardiol 1993; 71: 473-5. 3. Soloman AJ, Tracy CM, Swartz JF, Reagan KM, Karasik PE, Fletcher RD. Effect on coronary
artery anatomy of radiofrequency catheter ablation of atrial insertion sites of accessory pathways. J Am Coll Cardiol 1993; 21: 1440-4. 4. Calkins H, Sousa J, el-Atassi R, Rosenheck S, de Buitleir M, Kou WH, Kadish AH, Langberg JJ, Morady F. Diagnosis and cure of Wolff–Parkinson–White Syndrome or paroxysmal supraventricular tachycardia during a single electrophysiologic test. N Engl J Med 1991; 324: 1612-8. 5. Kosinski DJ, Burket MW, Durzinsky D. Occlusion of the left main coronary artery during radiofrequency ablation for the Wolff– Parkinson–White syndrome. Eur J Card Pacing Electrophysiol 1993; 3: 63-6.
6. Hope EJ, Haigney MC, Calkins H, Resar JR. Left main coronary thrombosis after radiofrequency ablation: successful treatment with percutaneous transluminal angioplasty. Am Heart J 1995; 129: 1217-9. 7. Dinckal H, Yucel O, Kirilmaz A, Karaca M, Kilicaslan F, Dokumaci B. Left anterior descending coronary artery occlusion after left lateral free wall accessory pathway ablation: what is the possible mechanism? Europace 2003; 5: 263-6. 8. Turkoğlu C, Aliyev F, Arat-Ozkan A, Gürmen T. Chronic total occlusion of left circumflex artery after radiofrequency ablation of left ventricular outflow tract tachycardia. Europace 2010; 12: 443-4.
337
