- Email: [email protected]
Arrhythmia Substrate Ablation for Nonischemic Cardiomyopathy
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY
VOL. 68, NO. 18, 2016
ª 2016 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 0735-1097/$36.00
PUBLISHED BY ELSEVIER
http://dx.doi.org/10.1016/j.jacc.2016.08.028
EDITORIAL COMMENT
Arrhythmia Substrate Ablation for Nonischemic Cardiomyopathy All or Some?* Usha B. Tedrow, MD, MSC, William G. Stevenson, MD
I
n both ischemic cardiomyopathy (ICM) and non-
prior myocarditis, “burnt-out” hypertrophic cardio-
ischemic cardiomyopathy (NICM), recurrent sus-
myopathy, and others. The exact etiology can be
tained monomorphic ventricular tachycardia
difficult to diagnose (3). In addition, the optimal
(VT) is usually due to re-entry through regions of
ablation strategy is not clear. Ablation may seek to
ventricular scar that characterize the arrhythmia
target specific inducible VTs, but hemodynamic
substrate. Percutaneous catheter ablation is an
intolerance and inconsistency in VT induction often
important
of
limits mapping during VT. Alternatively, during sinus
improving quality of life and reducing mortality as
adjunct,
offering
the
possibility
or paced rhythm, the arrhythmia substrate can be
well as reducing painful defibrillator shocks and heart
targeted, focusing on late potentials within the low-
failure hospitalizations (1,2). However, the success
voltage area, local abnormal ventricular activities,
rate of catheter ablation in NICM is lower than in
or pace mapping; or the entire low-voltage region can
ICM, likely related to differences in the arrhythmia
be targeted for ablation in a “scar homogenization”
substrate (3).
type of approach (6–11). Approaches vary among
During catheter mapping, the scar-related substrate is identified on the basis of the presence of low
laboratories, as do the procedural endpoints and assessment of success (12).
voltage (bipolar voltage is best validated) and
SEE PAGE 1990
abnormal electrograms. Although many patients with NICM with VT have large areas of low-voltage endo-
lan et al. (13) In this issue of the Journal, Göko g
cardial and/or epicardial scar similar to ICM, in others
report
the scar is largely intramural and thus difficult to
study of 2 ablation approaches in 93 patients with
identify and treat with standard mapping techniques
presumed scar-related VT, NICM, and areas of low
and catheter ablation (4,5). Still others have auto-
voltage (<1.5 mV in bipolar recordings). In group 1,
matic VTs that can be difficult to induce for mapping.
“standard” ablation was guided by inducible VT
Some of these differences are likely related to
(either
a
prospective,
mapping
when
multicenter,
stable
or
observational
targeting
the
variations in the disease processes causing NICM,
substrate for the induced VT QRS configuration).
which include genetic cardiomyopathies, sarcoidosis,
Mapping started on the endocardium, and epicardial mapping was performed only in the 53% of patients who still had VT induced after endocardial ablation. In group 2, ablation sought to “homogenize” the entire
*Editorials published in the Journal of the American College of Cardiology
low-voltage scar area with ablation targeting all
reflect the views of the authors and do not necessarily represent the
abnormal, low-voltage sites, including the endocar-
views of JACC or the American College of Cardiology.
dium and epicardium in all patients. It is not clear if
From the Arrhythmia Unit, Brigham and Women’s Hospital, Boston,
group 2 was assessed for inducibility at the outset, but
Massachusetts. Dr. Tedrow has received speaking honoraria and research
success in both groups was assessed by inducibility of
funds in the minor range from St. Jude Medical, Biosense Webster, and Boston Scientific. Dr. Stevenson is the holder of a patent for needle ablation consigned to Brigham and Women’s Hospital and shared with Biosense Webster.
VT at the end of the procedure. Outcomes were better in group 2, with fewer patients inducible for any VT (69% vs. 42%), although
2000
Tedrow and Stevenson
JACC VOL. 68, NO. 18, 2016 NOVEMBER 1, 2016:1999–2001
Arrhythmia Substrate Ablation for NICM
persistent inducibility of a clinical VT was not
substrate would likely skew the results of the study
different. Group 2 also had fewer procedural compli-
toward higher success rates in general, but particu-
cations and fewer patients with recurrent VT during
larly in the scar homogenization arm, as these pa-
follow-up of 14 months (64% vs. 39%). The in-
tients are more likely to have substrate accessible for
vestigators conclude that the substrate homogeniza-
ablation, rather than an intramural arrhythmia that
tion approach might be considered for the initial
might require mapping during VT for localization.
ablation strategy, but they note that the overall
The lower success rates noted in group 2 when scar
recurrence rate was higher than they previously re-
substrate was believed to be less accessible (septal,
ported for ICM (14).
midmyocardial,
Several
important
observations
and
caveats
accompanied this welcome comparison of ablation
epicardial
fat)
supported
this
contention. The increased use of mechanical hemodynamic
strategies in NICM. In contrast to this group’s pre-
support
vious study in ICM (14), the ablation approach in the
mostly vascular, in the standard ablation group
and
greater
number
of
complications,
present study was not randomized. Because of the
1 is also notable. Although hemodynamic support
heterogeneity in substrate of NICM, the lack of
can allow extended mapping during VT, its risks may
randomization was a significant potential source of
outweigh the benefit. When mapping during VT
confounding. Etiologic factors were not included in
is needed, we favor mapping regions selected
the multivariate model and may not have been
from substrate characteristics and then using only
balanced across groups. The 2 most common VT
brief periods (often <1 min) of induced VT for
substrate locations in NICM, basal septal and basal
mapping
lateral left ventricular scar, can be reasonably pre-
longer episodes and avoid mechanical hemodynamic
dicted on the basis of the VT QRS configuration.
support.
to
avoid
the
hemodynamic
stress
of
Basal septal VTs are often more difficult to ablate
Overall, this paper underscores the challenges in
and do not usually benefit from an epicardial
ablating VT in NICM substrates. A success rate
approach, in contrast to VTs that originate from the
of 64%, as found in the homogenization arm, is
basal lateral left ventricle. More than two-thirds of
still
patients in the present study had scar in the basal
recurrent
lateral left ventricle (either endocardial or epicar-
therapies. Future work on strategies to identify and
disappointing
for
implantable
patients
experiencing
cardioverter-defibrillator
dial), compared with fewer than 20% with septal
address arrhythmogenic scar substrate in difficult
areas of scar. The investigators excluded patients
locations
who did not have areas of low-voltage scar (108
strides forward.
will
be
essential
to
make
important
screened and 93 enrolled; 13.9% excluded), an exclusion that could occur only after initial catheter
REPRINT REQUESTS AND CORRESPONDENCE: Dr.
mapping. Furthermore, the operator would also
William G. Stevenson, Brigham & Women’s Hospital,
likely consider whether VT was inducible or not in
Cardiovascular Division, 75 Francis Street, Boston,
selecting the ablation approach. Eliminating patients
Massachusetts
without endocardial- or epicardial-identified scar
partners.org.
02115-6110.
E-mail:
wstevenson@
REFERENCES 1. Poole JE, Johnson GW, Hellkamp AS, et al. Prognostic importance of defibrillator shocks in patients with heart failure. N Engl J Med 2008; 359:1009–17. 2. Dinov B, Fiedler L, Schonbauer R, et al. Outcomes in catheter ablation of ventricular tachycardia in dilated nonischemic cardiomyopathy compared with ischemic cardiomyopathy: results from the Prospective Heart Centre of Leipzig VT (HELP-VT) Study. Circulation 2014;129:728–36. 3. Tokuda M, Tedrow UB, Kojodjojo P, et al. Catheter ablation of ventricular tachycardia in nonischemic heart disease. Circ Arrhythm Electrophysiol 2012;5:992–1000. 4. Kumar S, Barbhaiya CR, Sobieszczyk P, et al. Role of alternative interventional procedures when endo- and epicardial catheter ablation
attempts for ventricular arrhythmias fail. Circ Arrhythm Electrophysiol 2015;8:606–15. 5. Sapp JL, Beeckler C, Pike R, et al. Initial human feasibility of infusion needle catheter ablation for refractory ventricular tachycardia. Circulation 2013;128:2289–95. 6. Berruezo A, Fernandez-Armenta J, Andreu D, et al. Scar dechanneling: new method for scarrelated left ventricular tachycardia substrate ablation. Circ Arrhythm Electrophysiol 2015;8:326–36. 7. Carbucicchio C, Ahmad Raja N, Di Biase L, et al. High-density substrate-guided ventricular tachycardia ablation: role of activation mapping in an attempt to improve procedural effectiveness. Heart Rhythm 2013;10:1850–8. 8. Jais P, Maury P, Khairy P, et al. Elimination of local abnormal ventricular activities: a new end
point for substrate modification in patients with scar-related ventricular tachycardia. Circulation 2012;125:2184–96. 9. Piers SR, van Huls van Taxis CF, Tao Q, et al. Epicardial substrate mapping for ventricular tachycardia ablation in patients with nonischaemic cardiomyopathy: a new algorithm to differentiate between scar and viable myocardium developed by simultaneous integration of computed tomography and contrast-enhanced magnetic resonance imaging. Eur Heart J 2013; 34:586–96. 10. Soejima K, Suzuki M, Maisel WH, et al. Catheter ablation in patients with multiple and unstable ventricular tachycardias after myocardial infarction: short ablation lines guided by reentry circuit isthmuses and sinus rhythm mapping. Circulation 2001; 104:664–9.
Tedrow and Stevenson
JACC VOL. 68, NO. 18, 2016 NOVEMBER 1, 2016:1999–2001
Arrhythmia Substrate Ablation for NICM
11. Vergara P, Trevisi N, Ricco A, et al. Late potentials abolition as an additional technique for reduction of arrhythmia recurrence in scar related ventricular tachycardia ablation. J Cardiovasc
branch of the European Society of Cardiology (ESC), and the Heart Rhythm Society (HRS); in collaboration with the American College of Cardiology (ACC) and the American Heart Association
14. Di Biase L, Burkhardt JD, Lakkireddy D, et al. Ablation of stable VTs versus substrate ablation in ischemic cardiomyopathy: the VISTA randomized multicenter trial. J Am Coll Cardiol 2015;66:
Electrophysiol 2012;23:621–7.
(AHA). Heart Rhythm 2009;6:886–933.
2872–82.
12. Aliot
Almendral-
lan Y, Mohanty S, Gianni C, et al. Scar 13. Gökog
Garrote JM, et al. EHRA/HRS expert consensus on catheter ablation of ventricular arrhythmias: developed in a partnership with the European Heart Rhythm Association (EHRA), a registered
homogenization versus limited-substrate ablation in patients with nonischemic cardiomyopathy and ventricular tachycardia. J Am Coll Cardiol 2016;68:1990–8.
EM,
Stevenson
WG,
KEY WORDS mapping, scar homogenization, ventricular tachycardia
2001
VOL. 68, NO. 18, 2016
ª 2016 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 0735-1097/$36.00
PUBLISHED BY ELSEVIER
http://dx.doi.org/10.1016/j.jacc.2016.08.028
EDITORIAL COMMENT
Arrhythmia Substrate Ablation for Nonischemic Cardiomyopathy All or Some?* Usha B. Tedrow, MD, MSC, William G. Stevenson, MD
I
n both ischemic cardiomyopathy (ICM) and non-
prior myocarditis, “burnt-out” hypertrophic cardio-
ischemic cardiomyopathy (NICM), recurrent sus-
myopathy, and others. The exact etiology can be
tained monomorphic ventricular tachycardia
difficult to diagnose (3). In addition, the optimal
(VT) is usually due to re-entry through regions of
ablation strategy is not clear. Ablation may seek to
ventricular scar that characterize the arrhythmia
target specific inducible VTs, but hemodynamic
substrate. Percutaneous catheter ablation is an
intolerance and inconsistency in VT induction often
important
of
limits mapping during VT. Alternatively, during sinus
improving quality of life and reducing mortality as
adjunct,
offering
the
possibility
or paced rhythm, the arrhythmia substrate can be
well as reducing painful defibrillator shocks and heart
targeted, focusing on late potentials within the low-
failure hospitalizations (1,2). However, the success
voltage area, local abnormal ventricular activities,
rate of catheter ablation in NICM is lower than in
or pace mapping; or the entire low-voltage region can
ICM, likely related to differences in the arrhythmia
be targeted for ablation in a “scar homogenization”
substrate (3).
type of approach (6–11). Approaches vary among
During catheter mapping, the scar-related substrate is identified on the basis of the presence of low
laboratories, as do the procedural endpoints and assessment of success (12).
voltage (bipolar voltage is best validated) and
SEE PAGE 1990
abnormal electrograms. Although many patients with NICM with VT have large areas of low-voltage endo-
lan et al. (13) In this issue of the Journal, Göko g
cardial and/or epicardial scar similar to ICM, in others
report
the scar is largely intramural and thus difficult to
study of 2 ablation approaches in 93 patients with
identify and treat with standard mapping techniques
presumed scar-related VT, NICM, and areas of low
and catheter ablation (4,5). Still others have auto-
voltage (<1.5 mV in bipolar recordings). In group 1,
matic VTs that can be difficult to induce for mapping.
“standard” ablation was guided by inducible VT
Some of these differences are likely related to
(either
a
prospective,
mapping
when
multicenter,
stable
or
observational
targeting
the
variations in the disease processes causing NICM,
substrate for the induced VT QRS configuration).
which include genetic cardiomyopathies, sarcoidosis,
Mapping started on the endocardium, and epicardial mapping was performed only in the 53% of patients who still had VT induced after endocardial ablation. In group 2, ablation sought to “homogenize” the entire
*Editorials published in the Journal of the American College of Cardiology
low-voltage scar area with ablation targeting all
reflect the views of the authors and do not necessarily represent the
abnormal, low-voltage sites, including the endocar-
views of JACC or the American College of Cardiology.
dium and epicardium in all patients. It is not clear if
From the Arrhythmia Unit, Brigham and Women’s Hospital, Boston,
group 2 was assessed for inducibility at the outset, but
Massachusetts. Dr. Tedrow has received speaking honoraria and research
success in both groups was assessed by inducibility of
funds in the minor range from St. Jude Medical, Biosense Webster, and Boston Scientific. Dr. Stevenson is the holder of a patent for needle ablation consigned to Brigham and Women’s Hospital and shared with Biosense Webster.
VT at the end of the procedure. Outcomes were better in group 2, with fewer patients inducible for any VT (69% vs. 42%), although
2000
Tedrow and Stevenson
JACC VOL. 68, NO. 18, 2016 NOVEMBER 1, 2016:1999–2001
Arrhythmia Substrate Ablation for NICM
persistent inducibility of a clinical VT was not
substrate would likely skew the results of the study
different. Group 2 also had fewer procedural compli-
toward higher success rates in general, but particu-
cations and fewer patients with recurrent VT during
larly in the scar homogenization arm, as these pa-
follow-up of 14 months (64% vs. 39%). The in-
tients are more likely to have substrate accessible for
vestigators conclude that the substrate homogeniza-
ablation, rather than an intramural arrhythmia that
tion approach might be considered for the initial
might require mapping during VT for localization.
ablation strategy, but they note that the overall
The lower success rates noted in group 2 when scar
recurrence rate was higher than they previously re-
substrate was believed to be less accessible (septal,
ported for ICM (14).
midmyocardial,
Several
important
observations
and
caveats
accompanied this welcome comparison of ablation
epicardial
fat)
supported
this
contention. The increased use of mechanical hemodynamic
strategies in NICM. In contrast to this group’s pre-
support
vious study in ICM (14), the ablation approach in the
mostly vascular, in the standard ablation group
and
greater
number
of
complications,
present study was not randomized. Because of the
1 is also notable. Although hemodynamic support
heterogeneity in substrate of NICM, the lack of
can allow extended mapping during VT, its risks may
randomization was a significant potential source of
outweigh the benefit. When mapping during VT
confounding. Etiologic factors were not included in
is needed, we favor mapping regions selected
the multivariate model and may not have been
from substrate characteristics and then using only
balanced across groups. The 2 most common VT
brief periods (often <1 min) of induced VT for
substrate locations in NICM, basal septal and basal
mapping
lateral left ventricular scar, can be reasonably pre-
longer episodes and avoid mechanical hemodynamic
dicted on the basis of the VT QRS configuration.
support.
to
avoid
the
hemodynamic
stress
of
Basal septal VTs are often more difficult to ablate
Overall, this paper underscores the challenges in
and do not usually benefit from an epicardial
ablating VT in NICM substrates. A success rate
approach, in contrast to VTs that originate from the
of 64%, as found in the homogenization arm, is
basal lateral left ventricle. More than two-thirds of
still
patients in the present study had scar in the basal
recurrent
lateral left ventricle (either endocardial or epicar-
therapies. Future work on strategies to identify and
disappointing
for
implantable
patients
experiencing
cardioverter-defibrillator
dial), compared with fewer than 20% with septal
address arrhythmogenic scar substrate in difficult
areas of scar. The investigators excluded patients
locations
who did not have areas of low-voltage scar (108
strides forward.
will
be
essential
to
make
important
screened and 93 enrolled; 13.9% excluded), an exclusion that could occur only after initial catheter
REPRINT REQUESTS AND CORRESPONDENCE: Dr.
mapping. Furthermore, the operator would also
William G. Stevenson, Brigham & Women’s Hospital,
likely consider whether VT was inducible or not in
Cardiovascular Division, 75 Francis Street, Boston,
selecting the ablation approach. Eliminating patients
Massachusetts
without endocardial- or epicardial-identified scar
partners.org.
02115-6110.
E-mail:
wstevenson@
REFERENCES 1. Poole JE, Johnson GW, Hellkamp AS, et al. Prognostic importance of defibrillator shocks in patients with heart failure. N Engl J Med 2008; 359:1009–17. 2. Dinov B, Fiedler L, Schonbauer R, et al. Outcomes in catheter ablation of ventricular tachycardia in dilated nonischemic cardiomyopathy compared with ischemic cardiomyopathy: results from the Prospective Heart Centre of Leipzig VT (HELP-VT) Study. Circulation 2014;129:728–36. 3. Tokuda M, Tedrow UB, Kojodjojo P, et al. Catheter ablation of ventricular tachycardia in nonischemic heart disease. Circ Arrhythm Electrophysiol 2012;5:992–1000. 4. Kumar S, Barbhaiya CR, Sobieszczyk P, et al. Role of alternative interventional procedures when endo- and epicardial catheter ablation
attempts for ventricular arrhythmias fail. Circ Arrhythm Electrophysiol 2015;8:606–15. 5. Sapp JL, Beeckler C, Pike R, et al. Initial human feasibility of infusion needle catheter ablation for refractory ventricular tachycardia. Circulation 2013;128:2289–95. 6. Berruezo A, Fernandez-Armenta J, Andreu D, et al. Scar dechanneling: new method for scarrelated left ventricular tachycardia substrate ablation. Circ Arrhythm Electrophysiol 2015;8:326–36. 7. Carbucicchio C, Ahmad Raja N, Di Biase L, et al. High-density substrate-guided ventricular tachycardia ablation: role of activation mapping in an attempt to improve procedural effectiveness. Heart Rhythm 2013;10:1850–8. 8. Jais P, Maury P, Khairy P, et al. Elimination of local abnormal ventricular activities: a new end
point for substrate modification in patients with scar-related ventricular tachycardia. Circulation 2012;125:2184–96. 9. Piers SR, van Huls van Taxis CF, Tao Q, et al. Epicardial substrate mapping for ventricular tachycardia ablation in patients with nonischaemic cardiomyopathy: a new algorithm to differentiate between scar and viable myocardium developed by simultaneous integration of computed tomography and contrast-enhanced magnetic resonance imaging. Eur Heart J 2013; 34:586–96. 10. Soejima K, Suzuki M, Maisel WH, et al. Catheter ablation in patients with multiple and unstable ventricular tachycardias after myocardial infarction: short ablation lines guided by reentry circuit isthmuses and sinus rhythm mapping. Circulation 2001; 104:664–9.
Tedrow and Stevenson
JACC VOL. 68, NO. 18, 2016 NOVEMBER 1, 2016:1999–2001
Arrhythmia Substrate Ablation for NICM
11. Vergara P, Trevisi N, Ricco A, et al. Late potentials abolition as an additional technique for reduction of arrhythmia recurrence in scar related ventricular tachycardia ablation. J Cardiovasc
branch of the European Society of Cardiology (ESC), and the Heart Rhythm Society (HRS); in collaboration with the American College of Cardiology (ACC) and the American Heart Association
14. Di Biase L, Burkhardt JD, Lakkireddy D, et al. Ablation of stable VTs versus substrate ablation in ischemic cardiomyopathy: the VISTA randomized multicenter trial. J Am Coll Cardiol 2015;66:
Electrophysiol 2012;23:621–7.
(AHA). Heart Rhythm 2009;6:886–933.
2872–82.
12. Aliot
Almendral-
lan Y, Mohanty S, Gianni C, et al. Scar 13. Gökog
Garrote JM, et al. EHRA/HRS expert consensus on catheter ablation of ventricular arrhythmias: developed in a partnership with the European Heart Rhythm Association (EHRA), a registered
homogenization versus limited-substrate ablation in patients with nonischemic cardiomyopathy and ventricular tachycardia. J Am Coll Cardiol 2016;68:1990–8.
EM,
Stevenson
WG,
KEY WORDS mapping, scar homogenization, ventricular tachycardia
2001