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Arrhythmogenic substrates in the left atrium in patients with prior mitral valve surgery
Author’s Accepted Manuscript Arrhythmogenic substrates in the left atrium in patients with prior mitral valve surgery Hideharu Okamatsu, Ken Okumura, Junjirou Koyama www.elsevier.com/locate/buildenv
PII: DOI: Reference:
S1547-5271(16)31228-0S1547-5271(16)31157-2 http://dx.doi.org/10.1016/j.hrthm.2016.12.034 HRTHM6976
To appear in: Heart Rhythm Cite this article as: Hideharu Okamatsu, Ken Okumura and Junjirou Koyama, Arrhythmogenic substrates in the left atrium in patients with prior mitral valve surgery, Heart Rhythm, http://dx.doi.org/10.1016/j.hrthm.2016.12.034 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Arrhythmogenic Substrates in the Left Atrium in Patients With Prior Mitral Valve Surgery by Hideharu Okamatsu M.D., Ken Okumura M.D., Ph.D., Junjirou Koyama M.D., Ph.D.
From the Division of Cardiology, Saiseikai Kumamoto Hospital Cardiovascular Center, Kumamoto, Japan
There is no conflict of interest.
All Correspondence to: Ken Okumura, M.D. Division of Cardiology Saiseikai Kumamoto Hospital Cardiovascular Center Minami-ku, Chikami 5-3-1 Kumamoto, Japan 861-4193, Japan e-mail: [email protected]
Atrial tachycardia (AT) is an important late complication after cardiac surgery. Managing the patients with postoperative AT is sometimes difficult because the ventricular rate during AT is often rapid and hard to be controlled. Further, the symptom is intolerable in many cases. Antiarrhythmic medications have limited effects in terminating these ATs and preventing the recurrence. Radiofrequency catheter ablation (RFCA) has evolved as an effective, curative treatment for these ATs. AT occurring in patients with prior mitral valve (MV) surgery is much more complicated since the hemodynamic overload against the left atrium (LA) by primary MV disease promotes structural LA remodeling, resulting in the development of arrhythmogenic substrate in the LA. Further, concomitant Maze procedure performed in patients with atrial fibrillation (AF) adds new, iatrogenic lesions to the diseased LA. Although RFCA has been applied to ATs in patients with prior MV surgery, the data regarding the mechanism of these ATs and the long-term outcome of RFCA has been limited. In this issue of the Heart Rhythm, Enriquez et al. presented the electrophysiologic mechanisms of ATs occurring in patients with prior MV surgery and the outcome after RFCA.1 They found that macro-reentry was the predominant mechanism. The chamber of origin was the right atrium (RA) in 35 (52%) of the 67 patients studied, LA in 18 (27%) and both atria in the remaining 14 (21%). On the other hand, Chen et al. previously reported that of the 21 rheumatic heart disease patients with ATs after MV replacement, the chamber of AT rigin was the RA in 19 (90.5%),2 suggesting an arrhythmogenic substrate of ATs after the MV surgery being mainly in the RA, and acute success of RFCA was obtained in 95% without ablating the LA in almost
all patients. In this report, however, only 33% of the patients remained in stable sinus rhythm since the last procedure, and notably, the recurrence of new ATs originated from the LA or AF was common. Similar findings were noted by Enriquez et al.,1 and the patients who underwent only the cavotricuspid isthmus ablation had recurrences with AF and/or atypical flutter after the RFCA procedure. These results strongly suggest that atrial remodeling in the LA caused by primary MV disease is extensive and causes new atrial tachyarrhythmia. According to this hypothesis, even if the origin of ATs was only in the RA, concomitant LA ablation including pulmonary vein (PV) isolation and LA substrate modification at the time of RFCA may improve the outcome of RFCA. Enriquez et al. performed PV isolation in 56 of 67 patients (83.6%) although AF was detected before the procedure only in 28 of all patients.1 Such an aggressive LA ablation may improve the outcome of catheter ablation. Indeed, a freedom from atrial tachyarrhythmias after one or more procedure was 62% at 12 months, and was better than that reported by Chen et al.2 Masuda et al. reported that low voltage areas are associated with high inducibility of macro-reentrant ATs after PV isolation.3 They also showed that the distribution of low voltage areas is specific for each type of macro-reentrant AT: Patients with perimitral macro-reentrant AT frequently coincided with low voltage areas in the septal and anterior regions of the LA, and those with roof-dependent AT in the roof and posterior regions of the LA. Low voltage area in LA represents the presence of fibrotic tissue4 which may create an area of slow conduction that provide a substrate for reentry. Furthermore, the presence of low voltage area was an independent predictor of AF recurrence after PV isolation.5 These results indicate
that the presence of low voltage area in the LA in the patients with prior MV surgery may also be associated with increased risk of the recurrence of ATs originating from the LA and AF after RFCA procedure. Rolf et a. reported that additional ablation of low voltage area improved the outcome of RFCA for AF.6 During the procedure of RFCA for ATs occurring in patients with prior MV surgery, additional PV isolation and linear ablation along the low voltage area, if present, may prevent the recurrence or new occurrence of AT/AF. Further studies are needed to prove this. AF is common among patients undergoing MV surgery. Maze procedure is a well-established treatment for AF. Cardiothoracic Surgical Trials Network (CTSN) Investigators revealed results of a randomized trial on surgical ablation of AF during MV surgery,7 and concluded that the addition of AF ablation to MV surgery significantly increased the rate of freedom from AF at 1 year. Nevertheless, recurrence of atrial tachyarrhythmia, especially ATs, is a major clinical concern. Most of ATs after Maze procedure have origins in the LA.8 The difference in the origin of ATs between the reports by Enriquez et al.1 and Chen et al.2 seems to be attributed to presence or absence of the concomitant Maze procedure. In fact, almost half of the patients in the former report underwent Maze procedure, whereas no patients underwent Maze in the latter. Indeed, the former showed that AT originating from the LA was more frequently observed in patients with prior Maze procedure than in those without Maze (57.6% versus 38.2%, p=0.11).1 All of the 29 patients with prior Maze procedure and with PV assessment during RFCA for AT were found to have PV reconnection, and 8 of the 13 patients who underwent mitral isthmus line during surgical ablation had re-conduction
in the isthmus.1 Thus, reconnection in the ablation lines created by the prior Maze procedure can be another arrhythmogenic substrate of reentrant atrial tachyarrhythmias, indicating the importance of achieving the complete and durable lesions at the time of Maze surgery. Intraoperative electrophysiologic testing is useful in validating the complete electrical disconnection, but recovery of conduction can occur.9 Further studies should be required to create and confirm durable ablation lines during Maze procedure. AT after MV surgery not only deteriorates quality of life but increases the mortality.10 Although RFCA procedure for ATs can be accomplished successfully in almost all patients with prior MV surgery, the rate of late recurrence is still high. LA remodeling due to primary MV disease can cause new atrial tachyarrhythmias after ablation. In addition to ablating the clinical AT, evaluating the arrhythmogenic substrate of the atria and performing additional ablation may be needed to improve the outcome of the patients with prior MV disease.
Disclosures: None for all authors
1. Enriquez A, Santangeli P, Zado E, et al. Postoperative atrial tachycardias following mitral valve surgery: Mechanisms and outcomes of catheter ablation. Heart Rhythm, in press.
2. Chen H, Yang B, Ju W, Zhang F, Gu K, Li M, Wang J, Cao K, Chen M. Long-term outcome following ablation of atrial tachycardias occurring after mitral valve replacement in patients with rheumatic heart disease. Pacing Clin Electrophysiol 2013; 36:795-802.
3. Masuda M, Fujita M, Iida O, Okamoto S, Ishihara T, Nanto K, Kanda T, Shiraki T, Sunaga A, Matsuda Y, Uematsu M. Influence of underlying substrate on atrial tachyarrhythmias after pulmonary vein isolation. Heart Rhythm 2016; 13:870-878.
4. Oakes RS, Badger TJ, Kholmovski EG, et al. Detection and quantification of left atrial structural remodeling with delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation. Circulation 2009; 119:1758-1767.
5. Yamaguchi T, Tsuchiya T, Nagamoto Y, Miyamoto K, Murotani K, Okishige K, Takahashi N. Long-term results of pulmonary vein antrum isolation in patients with atrial fibrillation: an analysis in regards to substrates and pulmonary vein reconnections. Europace 2014; 16:511-520.
6. Rolf S, Kircher S, Arya A, Eitel C, Sommer P, Richter S, Gaspar T, Bollmann A, Altmann D, Piedra C, Hindricks G, Piorkowski C. Tailored atrial substrate
modification based on low-voltage areas in catheter ablation of atrial fibrillation. Circ Arrhythm Electrophysiol 2014; 7:825-833.
7. Gillinov AM, Gelijns AC, Parides MK, et al. Surgical ablation of atrial fibrillation during mitral-valve surgery. N Engl J Med 2015; 372:1399-1409.
8. Trumello C, Pozzoli A, Mazzone P, Nascimbene S, Bignami E, Cireddu M, Bella Della P, Alfieri O, Benussi S. Electrophysiological findings and long-term outcomes of percutaneous ablation of atrial arrhythmias after surgical ablation for atrial fibrillation. Eur J Cardiothorac Surg 2015; 49:273-280.
9. Zeng Y, Cui Y, Li Y, Liu X, Xu C, Han J, Meng X. Recurrent atrial arrhythmia after minimally invasive pulmonary vein isolation for atrial fibrillation. Ann Thorac Surg 2010; 90:510-515.
10. Bramer S, van Straten AHM, Soliman Hamad MA, van den Broek KC, Maessen JG, Berreklouw E. New-onset postoperative atrial fibrillation predicts late mortality after mitral valve surgery. Ann Thorac Surg 2011; 92:2091-2096.
PII: DOI: Reference:
S1547-5271(16)31228-0S1547-5271(16)31157-2 http://dx.doi.org/10.1016/j.hrthm.2016.12.034 HRTHM6976
To appear in: Heart Rhythm Cite this article as: Hideharu Okamatsu, Ken Okumura and Junjirou Koyama, Arrhythmogenic substrates in the left atrium in patients with prior mitral valve surgery, Heart Rhythm, http://dx.doi.org/10.1016/j.hrthm.2016.12.034 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Arrhythmogenic Substrates in the Left Atrium in Patients With Prior Mitral Valve Surgery by Hideharu Okamatsu M.D., Ken Okumura M.D., Ph.D., Junjirou Koyama M.D., Ph.D.
From the Division of Cardiology, Saiseikai Kumamoto Hospital Cardiovascular Center, Kumamoto, Japan
There is no conflict of interest.
All Correspondence to: Ken Okumura, M.D. Division of Cardiology Saiseikai Kumamoto Hospital Cardiovascular Center Minami-ku, Chikami 5-3-1 Kumamoto, Japan 861-4193, Japan e-mail: [email protected]
Atrial tachycardia (AT) is an important late complication after cardiac surgery. Managing the patients with postoperative AT is sometimes difficult because the ventricular rate during AT is often rapid and hard to be controlled. Further, the symptom is intolerable in many cases. Antiarrhythmic medications have limited effects in terminating these ATs and preventing the recurrence. Radiofrequency catheter ablation (RFCA) has evolved as an effective, curative treatment for these ATs. AT occurring in patients with prior mitral valve (MV) surgery is much more complicated since the hemodynamic overload against the left atrium (LA) by primary MV disease promotes structural LA remodeling, resulting in the development of arrhythmogenic substrate in the LA. Further, concomitant Maze procedure performed in patients with atrial fibrillation (AF) adds new, iatrogenic lesions to the diseased LA. Although RFCA has been applied to ATs in patients with prior MV surgery, the data regarding the mechanism of these ATs and the long-term outcome of RFCA has been limited. In this issue of the Heart Rhythm, Enriquez et al. presented the electrophysiologic mechanisms of ATs occurring in patients with prior MV surgery and the outcome after RFCA.1 They found that macro-reentry was the predominant mechanism. The chamber of origin was the right atrium (RA) in 35 (52%) of the 67 patients studied, LA in 18 (27%) and both atria in the remaining 14 (21%). On the other hand, Chen et al. previously reported that of the 21 rheumatic heart disease patients with ATs after MV replacement, the chamber of AT rigin was the RA in 19 (90.5%),2 suggesting an arrhythmogenic substrate of ATs after the MV surgery being mainly in the RA, and acute success of RFCA was obtained in 95% without ablating the LA in almost
all patients. In this report, however, only 33% of the patients remained in stable sinus rhythm since the last procedure, and notably, the recurrence of new ATs originated from the LA or AF was common. Similar findings were noted by Enriquez et al.,1 and the patients who underwent only the cavotricuspid isthmus ablation had recurrences with AF and/or atypical flutter after the RFCA procedure. These results strongly suggest that atrial remodeling in the LA caused by primary MV disease is extensive and causes new atrial tachyarrhythmia. According to this hypothesis, even if the origin of ATs was only in the RA, concomitant LA ablation including pulmonary vein (PV) isolation and LA substrate modification at the time of RFCA may improve the outcome of RFCA. Enriquez et al. performed PV isolation in 56 of 67 patients (83.6%) although AF was detected before the procedure only in 28 of all patients.1 Such an aggressive LA ablation may improve the outcome of catheter ablation. Indeed, a freedom from atrial tachyarrhythmias after one or more procedure was 62% at 12 months, and was better than that reported by Chen et al.2 Masuda et al. reported that low voltage areas are associated with high inducibility of macro-reentrant ATs after PV isolation.3 They also showed that the distribution of low voltage areas is specific for each type of macro-reentrant AT: Patients with perimitral macro-reentrant AT frequently coincided with low voltage areas in the septal and anterior regions of the LA, and those with roof-dependent AT in the roof and posterior regions of the LA. Low voltage area in LA represents the presence of fibrotic tissue4 which may create an area of slow conduction that provide a substrate for reentry. Furthermore, the presence of low voltage area was an independent predictor of AF recurrence after PV isolation.5 These results indicate
that the presence of low voltage area in the LA in the patients with prior MV surgery may also be associated with increased risk of the recurrence of ATs originating from the LA and AF after RFCA procedure. Rolf et a. reported that additional ablation of low voltage area improved the outcome of RFCA for AF.6 During the procedure of RFCA for ATs occurring in patients with prior MV surgery, additional PV isolation and linear ablation along the low voltage area, if present, may prevent the recurrence or new occurrence of AT/AF. Further studies are needed to prove this. AF is common among patients undergoing MV surgery. Maze procedure is a well-established treatment for AF. Cardiothoracic Surgical Trials Network (CTSN) Investigators revealed results of a randomized trial on surgical ablation of AF during MV surgery,7 and concluded that the addition of AF ablation to MV surgery significantly increased the rate of freedom from AF at 1 year. Nevertheless, recurrence of atrial tachyarrhythmia, especially ATs, is a major clinical concern. Most of ATs after Maze procedure have origins in the LA.8 The difference in the origin of ATs between the reports by Enriquez et al.1 and Chen et al.2 seems to be attributed to presence or absence of the concomitant Maze procedure. In fact, almost half of the patients in the former report underwent Maze procedure, whereas no patients underwent Maze in the latter. Indeed, the former showed that AT originating from the LA was more frequently observed in patients with prior Maze procedure than in those without Maze (57.6% versus 38.2%, p=0.11).1 All of the 29 patients with prior Maze procedure and with PV assessment during RFCA for AT were found to have PV reconnection, and 8 of the 13 patients who underwent mitral isthmus line during surgical ablation had re-conduction
in the isthmus.1 Thus, reconnection in the ablation lines created by the prior Maze procedure can be another arrhythmogenic substrate of reentrant atrial tachyarrhythmias, indicating the importance of achieving the complete and durable lesions at the time of Maze surgery. Intraoperative electrophysiologic testing is useful in validating the complete electrical disconnection, but recovery of conduction can occur.9 Further studies should be required to create and confirm durable ablation lines during Maze procedure. AT after MV surgery not only deteriorates quality of life but increases the mortality.10 Although RFCA procedure for ATs can be accomplished successfully in almost all patients with prior MV surgery, the rate of late recurrence is still high. LA remodeling due to primary MV disease can cause new atrial tachyarrhythmias after ablation. In addition to ablating the clinical AT, evaluating the arrhythmogenic substrate of the atria and performing additional ablation may be needed to improve the outcome of the patients with prior MV disease.
Disclosures: None for all authors
1. Enriquez A, Santangeli P, Zado E, et al. Postoperative atrial tachycardias following mitral valve surgery: Mechanisms and outcomes of catheter ablation. Heart Rhythm, in press.
2. Chen H, Yang B, Ju W, Zhang F, Gu K, Li M, Wang J, Cao K, Chen M. Long-term outcome following ablation of atrial tachycardias occurring after mitral valve replacement in patients with rheumatic heart disease. Pacing Clin Electrophysiol 2013; 36:795-802.
3. Masuda M, Fujita M, Iida O, Okamoto S, Ishihara T, Nanto K, Kanda T, Shiraki T, Sunaga A, Matsuda Y, Uematsu M. Influence of underlying substrate on atrial tachyarrhythmias after pulmonary vein isolation. Heart Rhythm 2016; 13:870-878.
4. Oakes RS, Badger TJ, Kholmovski EG, et al. Detection and quantification of left atrial structural remodeling with delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation. Circulation 2009; 119:1758-1767.
5. Yamaguchi T, Tsuchiya T, Nagamoto Y, Miyamoto K, Murotani K, Okishige K, Takahashi N. Long-term results of pulmonary vein antrum isolation in patients with atrial fibrillation: an analysis in regards to substrates and pulmonary vein reconnections. Europace 2014; 16:511-520.
6. Rolf S, Kircher S, Arya A, Eitel C, Sommer P, Richter S, Gaspar T, Bollmann A, Altmann D, Piedra C, Hindricks G, Piorkowski C. Tailored atrial substrate
modification based on low-voltage areas in catheter ablation of atrial fibrillation. Circ Arrhythm Electrophysiol 2014; 7:825-833.
7. Gillinov AM, Gelijns AC, Parides MK, et al. Surgical ablation of atrial fibrillation during mitral-valve surgery. N Engl J Med 2015; 372:1399-1409.
8. Trumello C, Pozzoli A, Mazzone P, Nascimbene S, Bignami E, Cireddu M, Bella Della P, Alfieri O, Benussi S. Electrophysiological findings and long-term outcomes of percutaneous ablation of atrial arrhythmias after surgical ablation for atrial fibrillation. Eur J Cardiothorac Surg 2015; 49:273-280.
9. Zeng Y, Cui Y, Li Y, Liu X, Xu C, Han J, Meng X. Recurrent atrial arrhythmia after minimally invasive pulmonary vein isolation for atrial fibrillation. Ann Thorac Surg 2010; 90:510-515.
10. Bramer S, van Straten AHM, Soliman Hamad MA, van den Broek KC, Maessen JG, Berreklouw E. New-onset postoperative atrial fibrillation predicts late mortality after mitral valve surgery. Ann Thorac Surg 2011; 92:2091-2096.