Radiofrequency Ablation of Symptomatic but Benign Ventricular Arrhythmias SINAN GURSOY, JOSEP BRUGADA, OLGA SOUZA, GUNTER STEUFER, ERIK ANDRIES, and PEDRO BRUGADA From the Cardiovascular Center, OLV Hospital, Aalst, Belgium
GURSOY, S., ET AL.: RadiofrequencyAblation of Symptomatic but Benign Ventricular Arrhythmias. Two cases are presented where ablation of severely symptomatic ventricular arrhythmias not responding to medical therapy was accomplished with radiofrequency current application. After a routine programmed stimulation protocol, a quadripolar ablation catheter with a 4-mm tip was advanced percutaneously into the left ventricle in one case and into the right ventricle in the second case; and after precise pace mapping, the arrhythmogenic focus was successfully ablated using radiofrequency current. The postablation ambulatory recording revealed virtual eradication of ventricular ectopy in both cases. In conclusion, in severely symptomatic cases of “benign” ventricular arrhythmias, radiofrequency ablation offers an effective therapeutic alternative. (PACE, Vol. 15, May 1992) radiofrequency, ablation, ventricular
Introduction Recently, radiofrequency energy has come to play a major role in the management of a variety of supraventricular a r r h y t h m i a ~ ~ lVarious -~ reports have shown it is a relatively safe and efficacious alternative for the ablation of accessory pathw a y ~ , ’ -the ~ atrioventricular node,4 and even for atrioventricular nodal reentrant t a ~ h y c a r d i aThe .~ reports of its use in ventricular arrhythmias remain parse.^-^ Two cases are reported where radiofrequency energy was used successfully in ablating the arrhythmogenic focus in two patients with severely symptomatic ventricular arrhythmias.
Case Number One The patient is a 30-year-old female with a history of palpitations for 9 years, associated with presyncope and exertional dyspnea. For the last 2
Address for reprints: Sinan Gursoy, M.D., Cardiovascular Center, OLV Hospital, 9300 Aalst, Belgium. Fax: 5 3 724587. Received October 1, 1991; revision December 11, 1991; accepted December 16, 1991.
738
years, there had been an increase in her symptoms as she started to have five to ten episodes of daily palpitations occurring at rest and with exercise, lasting a few minutes, and terminating spontaneously. Multiple ambulatory recordings revealed runs of nonsustained monomorphic ventricular tachycardia. She was started on sotalol 160 mg PO daily 3 months before admission without any success. An exercise test done 1month prior to admission while on sotalol revealed frequent unimorphic ventricular premature beats and nonsustained ventricular tachycardia (29 beats at 130 beatdmin). She was then referred for evaluation. Programmed stimulation was performed at three different basic drive cycle lengths (600 msec, 500 msec, 430 msec) using up to three extrastimuli with and without isoproterenol (3 pglkglmin) and no sustained arrhythmia could be induced. An increase in the frequency and duration of the ventricular arrhythmias was noted after isoproterenol, although still no sustained arrhythmias could be observed. Pace mapping was performed using a 7 French quadripolar ablation catheter with a 4-mm tip (Boston Scientific Corp., Watertown, MA, USA) and a QRS morphology homologous to the patients ventricular tachycardia was obtained from the right ventricular outflow tract (Fig. 1).
May 1992
PACE, Vol. 15
ABLATION OF BENIGN VENTRICULAR ARRHYTHMIAS
six ventricular ectopic beats/24 h, all with a different morphology). The patient was discharged on no antiarrhythmic medication and remains asymptomatic at a 2-month follow-up. Case Number Two
Figure 1. Pace mapping in patient 1 : Panel A shows the clinical tachycardia, while panel B shows the pace mapping.
Radiofrequency current was applied twice to that site (total energy 428 and 568 W) for a duration of 30 seconds using a HAT 200 unit (Osypka, GmBh, Grenzach-Wyhlen, Germany). Complete resolution of the ventricular ectopy was observed immediately following the first application. The fluoroscopy time was 1 2 minutes and the total procedure time was 70 minutes. The patient tolerated the procedure well and had no postoperative ECG changes or enzyme rise (all values within normal range). A postoperative ambulatory recording revealed abolition of the ventricular ectopy (total of
PACE, Vol. 15
The patient is a 30-year-old female with an extensive history of cardiac dysrhythmias. There was a 6-year history of recurrent episodes of syncope and palpitations. At an electrophysiological test 1 year ago, an atrial tachycardia originating from the anterolateral right atrium and AV nodal tachycardia were induced. At the time, no ventricular arrhythmias were induced, although frequent ventricular premature beats had been noted on several ambulatory recordings. Multiple drug regimens had been ineffective, including digoxin, beta blockers, flecainide, diphenylhydantoine, and propafenone. Torsade de pointes developed during an attempt to control the episodes with sotalol. A left heart catheterization arid a coronary angiography were performed and were both normal. An attempt at chemical ablation of the AV node was aborted due to anatomic limitations. An excision of the anterolateral right atrium abolished the clinical atrial tachycardia, but as an intraoperative electrophysiological study still revealed at least two other forms of atrial tachycardia, surgical cryoablation of the AV node was performed and a DDDR pacemaker implanted. Postoperatively, the patient did well for 2 months when she started complaining about being chronically tired and feeling slow and regular palpitations most of the day. Several ambulatory recordings revealed a dual chamber paced rhythm with frequent monomorphic ventricular bigeminy (> 20% of the total QRS complexes were ectopic ventricular beats). There was a correlation between the patient’s symptoms and the bigeminy. As atenolol, mexiletine, then finally flecainide failed to suppress the ectopy and the symptoms, the patient was admitted for radiofrequency ablation. Before the study, the patient was in ventricular bigeminy (Fig. 1A). A 6 French quadripolar catheter (1-cm interelectrode distance) was advanced from the right femoral vein and positioned at the right ventricular apex, to be used for stimulation and as a back-up external pacemaker in case of pacemaker malfunction during the application
May 1992
739
GURSOY, ET AL.
Figure 2. Panel A shows the patient's rhythm immediately before the ablation. Pane1 B shows the ventricdar pace mapping. Note the long pacing spike to QRS interval. Panel C shows the patient's rhythm immediately after the ablation.
.
of radiofrequency current.1° A 7 French quadripolar ablation catheter with a 4-mm tip was advanced from the right femoral artery to the left ventricle. Venticular stimulation using three different basic drives (600, 500, and 4 3 0 msec), with up to three extrastimuli, failed to induce any arrhythmias. Pace mapping was then performed until a QRS morphology homologous to the one of patient's ventricular premature beats was obtained (Fig. 2B). Radiofrequency current was applied to this site located in the lateral wall (Fig. 3). Two applications were given ( 4 2 5 and 5 3 9 W/sec), both for a duration of 25 seconds each. The first shock was effective and the bigeminal rhythm resolved immediately after the onset of the current application (Fig. 2C). The fluoroscopy time was 8 minutes, the total procedure time was 40 minutes. There were no postoperative enzyme rises or ECG changes. A postoperative ambulatory recording revealed rare ventricular ectopic beats (< 1% of total QRS complexes), but with a different morphology. The patient was discharged without any antiarrhythmic medication and remains asymptomatic at a 2-month follow-up.
740
Discussion The treatment of ventricular arrhythmias remains as one the major challenges in electrophysiology. Mapping for ventricular arrhythmias can be done by identifying the site of earliest activation or the site of slow conduction, or by ventricular pace mapping. The results with direct current ablation have been inconclusive in defining the best target area for energy delivery in patients with ventricular arrhythmias." The major factor limiting the success of ablative techniques in these patients is the anatomy of the reentrant circuit, as although the site of earlier activation can be identified, energy application at this point could be ineffective and might have to be directed to the area of slow conduction in some cases7 There is also evidence that the area of earliest activation and the area of slow conduction are not necessarily the same. The best results with catheter ablation in patients with ventricular arrhythmias have been obtained in patients with ventricular tachycardia due to bundle branch reentry.8.'2 In these cases, as there is a macroreentrant circuit, ablation of a critical limb for
May 1992
PACE, Vol. 15
ABLATION OF BENIGN VENTRICULAR ARRHYTHMIAS
ies are needed to define the role of ablation using radiofrequency current in the management of patients with ventricular arrhythmias. References 1. Scheinman MM, Laks MM, DiMarco J, et al. Cur-
2.
3.
4. 5.
6.
Figure 3. Panel A is a right anterior oblique projection, while panel B is a left anterior oblique projection showing the catheter at the ablation site (large arrowheads). Small arrowheads point to the back-up pacing catheter.
7.
a. reentry will be effective. Regardless of the mechanism of the ventricular arrhythmia, catheter ablation using radiofrequency current following pace mapping that reproduces a homologous QRS morphology may be effective in cases where the arrhythmogenic focus is small.’ This might specially hold true in patients with no underlying heart disease and monomorphic ventricular arrhythmias (including the patients with nonsustained arrhythmias), as in this subset of patients, the arrhythmogenic focus will be limited in size. In conclusion, in patients with no underlying heart disease and severely symptomatic but “benign” ventricular arrhythmias, ablation using radiofrequency current should be possible in some patients. The success rate can be high in patients with a small arrhythmogenic focus. Further stud-
PACE, Vol. 15
9.
10.
11.
12.
May 1992
rent role of catheter ablative procedures in patients with cardiac arrhythmias. Circulation 1991; 83: 2146-2153. Jackman WM, Wang X, Friday KJ, et al. Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current. N Engl J Med 1991; 324: 1605-1611. Calkins H, Sousa J, El-Atassi R, et al. Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test. N Engl J Med 1991; 324:1612-1618. Kuck KH, Schluter M, Geiger M, et al. Radiofrequency current ablation of accessory atrioventricular pathways. Lancet 1991; 337:1557-1561. Jackman WM, Wang X, Friday K, et al. Catheter ablation of atrioventricular junction using radiofrequency current in 17 patients: Comparison of standard and large-tip catheter electrodes. Circulation 1991; 83:1562-1576. Davis MJE, Murdock C. Radiofrequency catheter ablation of refractory ventricular tachycardia. PACE 1988; ii:725-729. Kuck KH, Schluter M, Geiger M, et al. Successful catheter ablation of human ventricular tachycardia with radiofrequency current guided by a n endocardial map of the area of slow conduction. PACE 1991; 14:1060- 1071. Langberg JL, Desai J, Dullet N, et al. Treatment of macroreentrant ventricular tachycardia with radiofrequency ablation of the right bundle branch. Am J Cardiol 1989; 63:lOlO-1013. Klein LS, Miles WM, Gering LE, et al. Radiofrequency catheter ablation of ventricular tachycardia in patients without structural heart disease. (abstract) J Am Coll Cardiol 1991; 17:91A. Chin MC, Rosenqvist M, Lee MA, et al. The effect of radiofrequency catheter ablation on permanent pacemakers: An experimental study. PACE 1990; 13123-29. Morady F, Kadish A, Rosenheck S, et al. Concealed entrainment as a guide for catheter ablation of ventricular tachycardia in patients with prior myocardial infarction. J Am Coll Cardiol 1991; 17: 678-689. Tchou P, Jazayeri M, Denker S, et al. Transcatheter electrical ablation of the right bundle: A method of treating macroreentrant ventricular tachycardia attributed to bundle branch reentry. Circulation 1988; 246-257.
74 1
GURSOY, S., ET AL.: RadiofrequencyAblation of Symptomatic but Benign Ventricular Arrhythmias. Two cases are presented where ablation of severely symptomatic ventricular arrhythmias not responding to medical therapy was accomplished with radiofrequency current application. After a routine programmed stimulation protocol, a quadripolar ablation catheter with a 4-mm tip was advanced percutaneously into the left ventricle in one case and into the right ventricle in the second case; and after precise pace mapping, the arrhythmogenic focus was successfully ablated using radiofrequency current. The postablation ambulatory recording revealed virtual eradication of ventricular ectopy in both cases. In conclusion, in severely symptomatic cases of “benign” ventricular arrhythmias, radiofrequency ablation offers an effective therapeutic alternative. (PACE, Vol. 15, May 1992) radiofrequency, ablation, ventricular
Introduction Recently, radiofrequency energy has come to play a major role in the management of a variety of supraventricular a r r h y t h m i a ~ ~ lVarious -~ reports have shown it is a relatively safe and efficacious alternative for the ablation of accessory pathw a y ~ , ’ -the ~ atrioventricular node,4 and even for atrioventricular nodal reentrant t a ~ h y c a r d i aThe .~ reports of its use in ventricular arrhythmias remain parse.^-^ Two cases are reported where radiofrequency energy was used successfully in ablating the arrhythmogenic focus in two patients with severely symptomatic ventricular arrhythmias.
Case Number One The patient is a 30-year-old female with a history of palpitations for 9 years, associated with presyncope and exertional dyspnea. For the last 2
Address for reprints: Sinan Gursoy, M.D., Cardiovascular Center, OLV Hospital, 9300 Aalst, Belgium. Fax: 5 3 724587. Received October 1, 1991; revision December 11, 1991; accepted December 16, 1991.
738
years, there had been an increase in her symptoms as she started to have five to ten episodes of daily palpitations occurring at rest and with exercise, lasting a few minutes, and terminating spontaneously. Multiple ambulatory recordings revealed runs of nonsustained monomorphic ventricular tachycardia. She was started on sotalol 160 mg PO daily 3 months before admission without any success. An exercise test done 1month prior to admission while on sotalol revealed frequent unimorphic ventricular premature beats and nonsustained ventricular tachycardia (29 beats at 130 beatdmin). She was then referred for evaluation. Programmed stimulation was performed at three different basic drive cycle lengths (600 msec, 500 msec, 430 msec) using up to three extrastimuli with and without isoproterenol (3 pglkglmin) and no sustained arrhythmia could be induced. An increase in the frequency and duration of the ventricular arrhythmias was noted after isoproterenol, although still no sustained arrhythmias could be observed. Pace mapping was performed using a 7 French quadripolar ablation catheter with a 4-mm tip (Boston Scientific Corp., Watertown, MA, USA) and a QRS morphology homologous to the patients ventricular tachycardia was obtained from the right ventricular outflow tract (Fig. 1).
May 1992
PACE, Vol. 15
ABLATION OF BENIGN VENTRICULAR ARRHYTHMIAS
six ventricular ectopic beats/24 h, all with a different morphology). The patient was discharged on no antiarrhythmic medication and remains asymptomatic at a 2-month follow-up. Case Number Two
Figure 1. Pace mapping in patient 1 : Panel A shows the clinical tachycardia, while panel B shows the pace mapping.
Radiofrequency current was applied twice to that site (total energy 428 and 568 W) for a duration of 30 seconds using a HAT 200 unit (Osypka, GmBh, Grenzach-Wyhlen, Germany). Complete resolution of the ventricular ectopy was observed immediately following the first application. The fluoroscopy time was 1 2 minutes and the total procedure time was 70 minutes. The patient tolerated the procedure well and had no postoperative ECG changes or enzyme rise (all values within normal range). A postoperative ambulatory recording revealed abolition of the ventricular ectopy (total of
PACE, Vol. 15
The patient is a 30-year-old female with an extensive history of cardiac dysrhythmias. There was a 6-year history of recurrent episodes of syncope and palpitations. At an electrophysiological test 1 year ago, an atrial tachycardia originating from the anterolateral right atrium and AV nodal tachycardia were induced. At the time, no ventricular arrhythmias were induced, although frequent ventricular premature beats had been noted on several ambulatory recordings. Multiple drug regimens had been ineffective, including digoxin, beta blockers, flecainide, diphenylhydantoine, and propafenone. Torsade de pointes developed during an attempt to control the episodes with sotalol. A left heart catheterization arid a coronary angiography were performed and were both normal. An attempt at chemical ablation of the AV node was aborted due to anatomic limitations. An excision of the anterolateral right atrium abolished the clinical atrial tachycardia, but as an intraoperative electrophysiological study still revealed at least two other forms of atrial tachycardia, surgical cryoablation of the AV node was performed and a DDDR pacemaker implanted. Postoperatively, the patient did well for 2 months when she started complaining about being chronically tired and feeling slow and regular palpitations most of the day. Several ambulatory recordings revealed a dual chamber paced rhythm with frequent monomorphic ventricular bigeminy (> 20% of the total QRS complexes were ectopic ventricular beats). There was a correlation between the patient’s symptoms and the bigeminy. As atenolol, mexiletine, then finally flecainide failed to suppress the ectopy and the symptoms, the patient was admitted for radiofrequency ablation. Before the study, the patient was in ventricular bigeminy (Fig. 1A). A 6 French quadripolar catheter (1-cm interelectrode distance) was advanced from the right femoral vein and positioned at the right ventricular apex, to be used for stimulation and as a back-up external pacemaker in case of pacemaker malfunction during the application
May 1992
739
GURSOY, ET AL.
Figure 2. Panel A shows the patient's rhythm immediately before the ablation. Pane1 B shows the ventricdar pace mapping. Note the long pacing spike to QRS interval. Panel C shows the patient's rhythm immediately after the ablation.
.
of radiofrequency current.1° A 7 French quadripolar ablation catheter with a 4-mm tip was advanced from the right femoral artery to the left ventricle. Venticular stimulation using three different basic drives (600, 500, and 4 3 0 msec), with up to three extrastimuli, failed to induce any arrhythmias. Pace mapping was then performed until a QRS morphology homologous to the one of patient's ventricular premature beats was obtained (Fig. 2B). Radiofrequency current was applied to this site located in the lateral wall (Fig. 3). Two applications were given ( 4 2 5 and 5 3 9 W/sec), both for a duration of 25 seconds each. The first shock was effective and the bigeminal rhythm resolved immediately after the onset of the current application (Fig. 2C). The fluoroscopy time was 8 minutes, the total procedure time was 40 minutes. There were no postoperative enzyme rises or ECG changes. A postoperative ambulatory recording revealed rare ventricular ectopic beats (< 1% of total QRS complexes), but with a different morphology. The patient was discharged without any antiarrhythmic medication and remains asymptomatic at a 2-month follow-up.
740
Discussion The treatment of ventricular arrhythmias remains as one the major challenges in electrophysiology. Mapping for ventricular arrhythmias can be done by identifying the site of earliest activation or the site of slow conduction, or by ventricular pace mapping. The results with direct current ablation have been inconclusive in defining the best target area for energy delivery in patients with ventricular arrhythmias." The major factor limiting the success of ablative techniques in these patients is the anatomy of the reentrant circuit, as although the site of earlier activation can be identified, energy application at this point could be ineffective and might have to be directed to the area of slow conduction in some cases7 There is also evidence that the area of earliest activation and the area of slow conduction are not necessarily the same. The best results with catheter ablation in patients with ventricular arrhythmias have been obtained in patients with ventricular tachycardia due to bundle branch reentry.8.'2 In these cases, as there is a macroreentrant circuit, ablation of a critical limb for
May 1992
PACE, Vol. 15
ABLATION OF BENIGN VENTRICULAR ARRHYTHMIAS
ies are needed to define the role of ablation using radiofrequency current in the management of patients with ventricular arrhythmias. References 1. Scheinman MM, Laks MM, DiMarco J, et al. Cur-
2.
3.
4. 5.
6.
Figure 3. Panel A is a right anterior oblique projection, while panel B is a left anterior oblique projection showing the catheter at the ablation site (large arrowheads). Small arrowheads point to the back-up pacing catheter.
7.
a. reentry will be effective. Regardless of the mechanism of the ventricular arrhythmia, catheter ablation using radiofrequency current following pace mapping that reproduces a homologous QRS morphology may be effective in cases where the arrhythmogenic focus is small.’ This might specially hold true in patients with no underlying heart disease and monomorphic ventricular arrhythmias (including the patients with nonsustained arrhythmias), as in this subset of patients, the arrhythmogenic focus will be limited in size. In conclusion, in patients with no underlying heart disease and severely symptomatic but “benign” ventricular arrhythmias, ablation using radiofrequency current should be possible in some patients. The success rate can be high in patients with a small arrhythmogenic focus. Further stud-
PACE, Vol. 15
9.
10.
11.
12.
May 1992
rent role of catheter ablative procedures in patients with cardiac arrhythmias. Circulation 1991; 83: 2146-2153. Jackman WM, Wang X, Friday KJ, et al. Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current. N Engl J Med 1991; 324: 1605-1611. Calkins H, Sousa J, El-Atassi R, et al. Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test. N Engl J Med 1991; 324:1612-1618. Kuck KH, Schluter M, Geiger M, et al. Radiofrequency current ablation of accessory atrioventricular pathways. Lancet 1991; 337:1557-1561. Jackman WM, Wang X, Friday K, et al. Catheter ablation of atrioventricular junction using radiofrequency current in 17 patients: Comparison of standard and large-tip catheter electrodes. Circulation 1991; 83:1562-1576. Davis MJE, Murdock C. Radiofrequency catheter ablation of refractory ventricular tachycardia. PACE 1988; ii:725-729. Kuck KH, Schluter M, Geiger M, et al. Successful catheter ablation of human ventricular tachycardia with radiofrequency current guided by a n endocardial map of the area of slow conduction. PACE 1991; 14:1060- 1071. Langberg JL, Desai J, Dullet N, et al. Treatment of macroreentrant ventricular tachycardia with radiofrequency ablation of the right bundle branch. Am J Cardiol 1989; 63:lOlO-1013. Klein LS, Miles WM, Gering LE, et al. Radiofrequency catheter ablation of ventricular tachycardia in patients without structural heart disease. (abstract) J Am Coll Cardiol 1991; 17:91A. Chin MC, Rosenqvist M, Lee MA, et al. The effect of radiofrequency catheter ablation on permanent pacemakers: An experimental study. PACE 1990; 13123-29. Morady F, Kadish A, Rosenheck S, et al. Concealed entrainment as a guide for catheter ablation of ventricular tachycardia in patients with prior myocardial infarction. J Am Coll Cardiol 1991; 17: 678-689. Tchou P, Jazayeri M, Denker S, et al. Transcatheter electrical ablation of the right bundle: A method of treating macroreentrant ventricular tachycardia attributed to bundle branch reentry. Circulation 1988; 246-257.
74 1
