254
Brief Communications
American
January 1992 Heart Journal
"i
Fig. 2. The ectopic atria1 tachycardia (EAT) is abruptly converted into sinus beats by manipulating the ablation catheter. From the top: Calibration line (50 msec/division); surface leads I, AVF, VI, and intracardiac electrograms; HBE, His bundle electrogram; LRA, low right atria1 electrogram; HRA, high right atria1 electrogram. The hexapolar catheter was advanced into the heart from the superior vena cava. Its distal and proximal poles are used to record HRA and LRA, respectively (see Fig. 1). LAl, Left atria1 electrogram 1 (recorded from the distal pole of the quadripolar catheter that is placed in the posterolateral left atrium, indicated by arrow in Fig. 1). LA2, Left atria1 electrogram 2 (recorded from the distal pole of the left atria1 ablation catheter). Note that during EAT the earliest atria1 depolarization is recorded in LA2. Note also in lead I the P wave is negative during EAT and positive during sinus beats.
(807 U/L) but with a normal MB band fraction (4 % ). A follow-up echocardiogram showed an improved left ventricular ejection fraction (68%) and a small amount of pericardial effusion, which spontaneously resolved 2 weeks later. The follow-up electrocardiogram showed normal sinus rhythm. The patient was symptom-free and drug-free in the 11 months of follow-up. In this patient during manipulation of the mapping catheter the incessant EAT was suddenly converted into sinus beats when the catheter tip pressed the specific site of the left atrium. This is analogous to the sign of “disappearance of preexcitation related to the pressure of the catheter on the accessory pathway’@ in localizing the site of fulguration for treating the preexcitation syndrome. This site is also the earliest site of activation of the EAT. Fulguration of this site cured the patient’s EAT. It is likely that the ablation catheter was in the left atria1 appendage, as suggested by the chest radiographs. Because the right atria1 appendage is a favorable site for successful catheter ablation of right atria1 EAT,3 it stands to reason that catheter ablation may also be successful if the focus is inside the left atria1 appendage. For each individual shock, Gillette et a1.3 used 1 to 5 joules/kg of energy, with a cumulative energy of up to 15 joules/kg (one to three shocks) for each individual patient. DC ablation of the left atria1 EAT was not attempted for fear of embolization of gas or parts of the catheter. While our case of a left atria1 EAT was successfully ablated by a relatively large dose of energy (close to 6 joules/kg) without the development of any problems, a risk still exists. In light of a recent report of successful catheter ablation of left EAT by radiofrequency in an adult,7 DC ablation should not be used until radiofrequency ablation, if available, has first been attempted. REFERENCES
1. Mehta AV, Sanchez GR, Sacks EJ, Casta A, Dunn JM, ner RM. Ectopic atria1 tachycardia in children: clinical
Donchar-
2.
3.
4.
5.
6. 7.
acteristics, management and follow-up. J Am Co11 Cardiol 1988;11:379-85. Ott DA, Gillette PC, Garson A, Cooley DA, Reul GJ, McNamara DG. Surgical management of refractory supraventricular tachycardia in infants and children. J Am Co11 Cardiol 1985;5:124-9. Gillette PC, Wampler DG, Garson A, Zinner A, Ott D, Cooley D. Treatment of atria1 automatic tachycardia by ablation procedures. J Am Co11 Cardiol 1985;6:405-9. Davis J, Scheinman MM, Ruder MA, Griffin JC, Herre JM, Finkebeiner WE, Chin MC, Eldar M. Ablation of cardiac tissues by an electrode catheter technique for treatment of ectopic atrial supraventricular tachycardia in adults. Circulation 1986;74:1044-53. Gillette PC, Garson A Jr. Electrophysiologic and pharmacologic characteristics of automatic ectopic atria1 tachycardia. Circulation 1977;56:571-5. Warin JF, Haissaguerre M. Fulguration of accessory pathways in any location: report of seventy cases. PACE 1989;12:215-8. Margolis PD, Roman CA, Moulton KP, Calame J, Wang X, Lazzara R, Jackman WM. Radiofrequency catheter ablation of left and right ectopic atria1 tachycardia [Abstract]. Circulation 1990;82:111-718.
Oral sotalol in pediatric tachycardia Vincenzo Ventriglia,
atrial ectopic
Colloridi, MD, Cesare Perri, MD, and Giuseppe Critelli,
MD, Flavia MD. Rome, Italy
Sotalol has received increasing attention as an antiarrhythmic agent that combines class II beta-blocking properties From the Departments University of Rome Reprint 4/4/33473
requests:
“La
of Pediatric Sapienza.”
Giuseppe
Critelli,
Cardiology
and Cardiovascular
MD, Via Ceresio,
11.00199
Disease, Rome,
Italy.
volume
123
Number
1
Brief Communications
255
Fig. 1. Patient No. 2. A, Narrow QRS tachycardia with first-degree AV block and 1:l AV conduction. B, Intravenous bolus of ATP (5 mg) induces second-degree AV block with persistence of atria1 tachycardia, thus confirming atrial origin of arrhythmia. Table
I. Treatment
Patient No.
D, Digitalis;
Sex
Age at onset
F*
4yr
F
Prenatal
F
data
Age at referral
Tachycardia rate (beatslmin)
Dilated cardiomyopathy
Previous treatment
Effective dose of sotalol (mglkgjday)
4 yr
160-220
?
9 days
260-300
+
W,F,V
8.0
Birth
4mo
210-250
-
D,P,F,V,A
8.0
M
Birth
20 days
215-300
-
W
5.0
F
Prenatal
4 days
200-270
-
W’
8.0
Pj, prop&none; V, verapamil; P, propanolol; *Patient underwent Fontan procedure. tNumbers in parenthesis indicate values before treatment.
D,Pf,V
F, flecainide;
4.0
Heart rate on sotalol (beatslmin)
QRS on sotalol
60-80 (sinus rhythm) 110-130 (sinus rhythm) 110-130 (sinus rhythm) 120-130 (sinus rhythm) 120-130 (sinus rhythm)
80
400 (39O)T
12
70
410 (425)t
11
80
380 (370)t
11
70
380 (370)t
7
70
410 (390)T
4
h.4
QTC on sotalol
(met)
Follow-up (mo)
A, amiodarone.
with the class III ability to prolong cardiac repolarizathere are few reports on the antiarrhythtion. 1,2 However, mic activity of sotalol in the pediatric age group.3, 4 We describe five children with atrial ectopic tachycardia (AET) refractory to conventional treatment, in whom oral therapy with sotalol allowed restoration of stable sinus rhythm. The mean age of the patients (four girls and one boy) was 10.7 months, with a range of 4 days to 5 years. Clinical and ECG characteristics are shown in Table I. One patient had undergone a Fontan procedure 1 year previously. Age at onset of tachycardia ranged from before birth to 4 years. The maximum rate of tachycardia ranged from 200 to 300 beats/min (mean 269 beats/min). One patient had presyncope when first seen. Echocardiographic examination showed dilated cardiomyopathy in one patient. Results of thyroid function tests were normal in all patients. The diagnosis of AET was based on the following criteria: (1) rate
of tachycardia inappropriate for age, (2) wide variability in the R-R interval from minute to minute and hour to hour, (3) presence of the “warm-up” phenomenon, (4) distinct P wave configuration, and (5) occurrence of spontaneous or adenosine triphosphate-induced second-degree atrioventricular (AV) block, with persistence of atria1 tachycardia (Fig. 1). The tachycardia was incessant (present more than 90% of the time) in two patients and repetitive (present more than 50% of the time) in three. During the tachycardia narrow QRS complexes were present in all but two patients, in whom aberrant ventricular conduction occurred at high rates (Fig. 2). Treatment with conventional antiarrhythmic drugs (Table I) proved to be ineffective in all patients, and oral therapy with racemic sotalol at an initial dose of 2.5 mg/kg/day was instituted while they were receiving digitalis. The dosage of the drug was subsequently increased up to a maxi-
256
Brief Communications
American
Fig. 2. Patient No. 4. A, Two episodes of AET with ventricular aberrance. phenomenon is evident. B, Stable sinus rhythm during sotalol therapy.
mum of 8 mg/kg/day and was determined on the basis of the clinical response. Suggestions for the maintenance dosages or treatment withdrawal were based on suppression of tachycardia or the appearance of intolerable side effects, respectively. After 4 to 7 days of treatment, normal sinus rhythm was restored in all patients, with no recurrences of tachycardia during the follow-up period (mean 9.0 months, range 4 to 12 months). Improvement in left ventricular ejection fraction was observed on the echocardiogram of the patient with dilated cardiomyopathy. No adverse reactions were noted during treatment, and the QRS and corrected QT intervals remained normal in all patients. AET is an uncommon type of supraventricular tachycardia that occurs predominantly in children. This arrhythmia is frequently resistant to conventional treatment and has been reported to be the cause of dilated cardiomyopathy. Surgical or catheter ablation of the tachycardia focus is recommended,5 but inconsistent results have been reported with such therapeutic procedures. On the other hand, spontaneous resolution of AET in children has been observed,4 so that therapeutic attempts with the use of new antiarrhythmic agents seem to be reasonable. In our patients, in whom standard treatment was unsuccessful, complete therapeutic success was reached with the use of sotalol, and improvement in left ventricular function was observed in one patient with dilated cardiomyopathy. Oral sotalol has been used rarely in the treatment of AET in infancy. Complete therapeutic success was achieved in two neonates by Bowman et a1.,3 whereas in the series of Koike et a1.4 sinus rhythm was restored in only one of four trials. The difference in success rates may be ascribed to the higher doses used in our study. Unlike d-sotalol, which exerts a predominantly class III antiarrhythmic action, racemic sotalol as used in our patients produces beta-adrenergic receptor blockade and a class III antiarrhythmic effect. Such a combination may account for the success in our pa-
In both instances
January 1992 Heart Journal
“warm-up”
tients, since a relatively high rate of efficacy in the control of AET in children has been reported with the separate use of amiodarone (a class III antiarrhythmic drug) and betablocking agents.’ In terms of side effects, an advantage could be derived from the association between beta blockade and class III antiarrhythmic action, the former possibly resulting in attenuation of lengthening of the action potential duration as a result of the latter. This peculiarity might be beneficial especially in young infants, inasmuch as a decreased sensitivity of developing cardiac tissues to class III antiarrhythmic agents has been demonstrated.6 Indeed, in two neonates in this series in whom tachycardia had been detected before the birth, a relatively high dose of sotalol could have been used. In spite of this, in none of them was the corrected QT interval affected significantly by the treatment. Nevertheless, the tolerability and safety of this agent in the pediatric age group needs to be defined in a larger series.
REFERENCES
1. Singh BN, Nademanee K. Sotalol: a beta-blocker with unique antiarrhythmic properties. AM HEART J 1987;114:121-39. 2. Mehta A, Sanchez GR, Saks BJ, Casta A, Dunn JM, Donner RM. Ectopic automatic atria1 tachycardia in children: clinical characteristics, management and follow-up. J Am Co11 Cardiol 1988;11:379-85.
3. Bowman E, Paes BA, Way RC. Oral sotalol in neonatal supraventriculsr tachycardia. Acta Pediatr Stand 1988;77:171. 4. Koike K, Hesslein PS, Finlay CD, Williams WG, Izukawa T, Freedom RM. Atria1 automatic tachycardia in children. Am J Cardiol 1988;61:1127-30. 5. Gillette PC, Wampler DG, Garson A, Zinner A, Ott D, Cooley D. Treatment of atrial automatic tachycsrdia by ablation procedures. J Am Co11 Cardiol 1985;6:405-9. 6. Yabek SM, Kato R, Ikeda N, Singh BN. Cellular electrophysiologic responses of isolated neonatal and adult cardiac fibers to d-sotalol. J Am Co11 Cardiol 1988;11:1094-9.
Brief Communications
American
January 1992 Heart Journal
"i
Fig. 2. The ectopic atria1 tachycardia (EAT) is abruptly converted into sinus beats by manipulating the ablation catheter. From the top: Calibration line (50 msec/division); surface leads I, AVF, VI, and intracardiac electrograms; HBE, His bundle electrogram; LRA, low right atria1 electrogram; HRA, high right atria1 electrogram. The hexapolar catheter was advanced into the heart from the superior vena cava. Its distal and proximal poles are used to record HRA and LRA, respectively (see Fig. 1). LAl, Left atria1 electrogram 1 (recorded from the distal pole of the quadripolar catheter that is placed in the posterolateral left atrium, indicated by arrow in Fig. 1). LA2, Left atria1 electrogram 2 (recorded from the distal pole of the left atria1 ablation catheter). Note that during EAT the earliest atria1 depolarization is recorded in LA2. Note also in lead I the P wave is negative during EAT and positive during sinus beats.
(807 U/L) but with a normal MB band fraction (4 % ). A follow-up echocardiogram showed an improved left ventricular ejection fraction (68%) and a small amount of pericardial effusion, which spontaneously resolved 2 weeks later. The follow-up electrocardiogram showed normal sinus rhythm. The patient was symptom-free and drug-free in the 11 months of follow-up. In this patient during manipulation of the mapping catheter the incessant EAT was suddenly converted into sinus beats when the catheter tip pressed the specific site of the left atrium. This is analogous to the sign of “disappearance of preexcitation related to the pressure of the catheter on the accessory pathway’@ in localizing the site of fulguration for treating the preexcitation syndrome. This site is also the earliest site of activation of the EAT. Fulguration of this site cured the patient’s EAT. It is likely that the ablation catheter was in the left atria1 appendage, as suggested by the chest radiographs. Because the right atria1 appendage is a favorable site for successful catheter ablation of right atria1 EAT,3 it stands to reason that catheter ablation may also be successful if the focus is inside the left atria1 appendage. For each individual shock, Gillette et a1.3 used 1 to 5 joules/kg of energy, with a cumulative energy of up to 15 joules/kg (one to three shocks) for each individual patient. DC ablation of the left atria1 EAT was not attempted for fear of embolization of gas or parts of the catheter. While our case of a left atria1 EAT was successfully ablated by a relatively large dose of energy (close to 6 joules/kg) without the development of any problems, a risk still exists. In light of a recent report of successful catheter ablation of left EAT by radiofrequency in an adult,7 DC ablation should not be used until radiofrequency ablation, if available, has first been attempted. REFERENCES
1. Mehta AV, Sanchez GR, Sacks EJ, Casta A, Dunn JM, ner RM. Ectopic atria1 tachycardia in children: clinical
Donchar-
2.
3.
4.
5.
6. 7.
acteristics, management and follow-up. J Am Co11 Cardiol 1988;11:379-85. Ott DA, Gillette PC, Garson A, Cooley DA, Reul GJ, McNamara DG. Surgical management of refractory supraventricular tachycardia in infants and children. J Am Co11 Cardiol 1985;5:124-9. Gillette PC, Wampler DG, Garson A, Zinner A, Ott D, Cooley D. Treatment of atria1 automatic tachycardia by ablation procedures. J Am Co11 Cardiol 1985;6:405-9. Davis J, Scheinman MM, Ruder MA, Griffin JC, Herre JM, Finkebeiner WE, Chin MC, Eldar M. Ablation of cardiac tissues by an electrode catheter technique for treatment of ectopic atrial supraventricular tachycardia in adults. Circulation 1986;74:1044-53. Gillette PC, Garson A Jr. Electrophysiologic and pharmacologic characteristics of automatic ectopic atria1 tachycardia. Circulation 1977;56:571-5. Warin JF, Haissaguerre M. Fulguration of accessory pathways in any location: report of seventy cases. PACE 1989;12:215-8. Margolis PD, Roman CA, Moulton KP, Calame J, Wang X, Lazzara R, Jackman WM. Radiofrequency catheter ablation of left and right ectopic atria1 tachycardia [Abstract]. Circulation 1990;82:111-718.
Oral sotalol in pediatric tachycardia Vincenzo Ventriglia,
atrial ectopic
Colloridi, MD, Cesare Perri, MD, and Giuseppe Critelli,
MD, Flavia MD. Rome, Italy
Sotalol has received increasing attention as an antiarrhythmic agent that combines class II beta-blocking properties From the Departments University of Rome Reprint 4/4/33473
requests:
“La
of Pediatric Sapienza.”
Giuseppe
Critelli,
Cardiology
and Cardiovascular
MD, Via Ceresio,
11.00199
Disease, Rome,
Italy.
volume
123
Number
1
Brief Communications
255
Fig. 1. Patient No. 2. A, Narrow QRS tachycardia with first-degree AV block and 1:l AV conduction. B, Intravenous bolus of ATP (5 mg) induces second-degree AV block with persistence of atria1 tachycardia, thus confirming atrial origin of arrhythmia. Table
I. Treatment
Patient No.
D, Digitalis;
Sex
Age at onset
F*
4yr
F
Prenatal
F
data
Age at referral
Tachycardia rate (beatslmin)
Dilated cardiomyopathy
Previous treatment
Effective dose of sotalol (mglkgjday)
4 yr
160-220
?
9 days
260-300
+
W,F,V
8.0
Birth
4mo
210-250
-
D,P,F,V,A
8.0
M
Birth
20 days
215-300
-
W
5.0
F
Prenatal
4 days
200-270
-
W’
8.0
Pj, prop&none; V, verapamil; P, propanolol; *Patient underwent Fontan procedure. tNumbers in parenthesis indicate values before treatment.
D,Pf,V
F, flecainide;
4.0
Heart rate on sotalol (beatslmin)
QRS on sotalol
60-80 (sinus rhythm) 110-130 (sinus rhythm) 110-130 (sinus rhythm) 120-130 (sinus rhythm) 120-130 (sinus rhythm)
80
400 (39O)T
12
70
410 (425)t
11
80
380 (370)t
11
70
380 (370)t
7
70
410 (390)T
4
h.4
QTC on sotalol
(met)
Follow-up (mo)
A, amiodarone.
with the class III ability to prolong cardiac repolarizathere are few reports on the antiarrhythtion. 1,2 However, mic activity of sotalol in the pediatric age group.3, 4 We describe five children with atrial ectopic tachycardia (AET) refractory to conventional treatment, in whom oral therapy with sotalol allowed restoration of stable sinus rhythm. The mean age of the patients (four girls and one boy) was 10.7 months, with a range of 4 days to 5 years. Clinical and ECG characteristics are shown in Table I. One patient had undergone a Fontan procedure 1 year previously. Age at onset of tachycardia ranged from before birth to 4 years. The maximum rate of tachycardia ranged from 200 to 300 beats/min (mean 269 beats/min). One patient had presyncope when first seen. Echocardiographic examination showed dilated cardiomyopathy in one patient. Results of thyroid function tests were normal in all patients. The diagnosis of AET was based on the following criteria: (1) rate
of tachycardia inappropriate for age, (2) wide variability in the R-R interval from minute to minute and hour to hour, (3) presence of the “warm-up” phenomenon, (4) distinct P wave configuration, and (5) occurrence of spontaneous or adenosine triphosphate-induced second-degree atrioventricular (AV) block, with persistence of atria1 tachycardia (Fig. 1). The tachycardia was incessant (present more than 90% of the time) in two patients and repetitive (present more than 50% of the time) in three. During the tachycardia narrow QRS complexes were present in all but two patients, in whom aberrant ventricular conduction occurred at high rates (Fig. 2). Treatment with conventional antiarrhythmic drugs (Table I) proved to be ineffective in all patients, and oral therapy with racemic sotalol at an initial dose of 2.5 mg/kg/day was instituted while they were receiving digitalis. The dosage of the drug was subsequently increased up to a maxi-
256
Brief Communications
American
Fig. 2. Patient No. 4. A, Two episodes of AET with ventricular aberrance. phenomenon is evident. B, Stable sinus rhythm during sotalol therapy.
mum of 8 mg/kg/day and was determined on the basis of the clinical response. Suggestions for the maintenance dosages or treatment withdrawal were based on suppression of tachycardia or the appearance of intolerable side effects, respectively. After 4 to 7 days of treatment, normal sinus rhythm was restored in all patients, with no recurrences of tachycardia during the follow-up period (mean 9.0 months, range 4 to 12 months). Improvement in left ventricular ejection fraction was observed on the echocardiogram of the patient with dilated cardiomyopathy. No adverse reactions were noted during treatment, and the QRS and corrected QT intervals remained normal in all patients. AET is an uncommon type of supraventricular tachycardia that occurs predominantly in children. This arrhythmia is frequently resistant to conventional treatment and has been reported to be the cause of dilated cardiomyopathy. Surgical or catheter ablation of the tachycardia focus is recommended,5 but inconsistent results have been reported with such therapeutic procedures. On the other hand, spontaneous resolution of AET in children has been observed,4 so that therapeutic attempts with the use of new antiarrhythmic agents seem to be reasonable. In our patients, in whom standard treatment was unsuccessful, complete therapeutic success was reached with the use of sotalol, and improvement in left ventricular function was observed in one patient with dilated cardiomyopathy. Oral sotalol has been used rarely in the treatment of AET in infancy. Complete therapeutic success was achieved in two neonates by Bowman et a1.,3 whereas in the series of Koike et a1.4 sinus rhythm was restored in only one of four trials. The difference in success rates may be ascribed to the higher doses used in our study. Unlike d-sotalol, which exerts a predominantly class III antiarrhythmic action, racemic sotalol as used in our patients produces beta-adrenergic receptor blockade and a class III antiarrhythmic effect. Such a combination may account for the success in our pa-
In both instances
January 1992 Heart Journal
“warm-up”
tients, since a relatively high rate of efficacy in the control of AET in children has been reported with the separate use of amiodarone (a class III antiarrhythmic drug) and betablocking agents.’ In terms of side effects, an advantage could be derived from the association between beta blockade and class III antiarrhythmic action, the former possibly resulting in attenuation of lengthening of the action potential duration as a result of the latter. This peculiarity might be beneficial especially in young infants, inasmuch as a decreased sensitivity of developing cardiac tissues to class III antiarrhythmic agents has been demonstrated.6 Indeed, in two neonates in this series in whom tachycardia had been detected before the birth, a relatively high dose of sotalol could have been used. In spite of this, in none of them was the corrected QT interval affected significantly by the treatment. Nevertheless, the tolerability and safety of this agent in the pediatric age group needs to be defined in a larger series.
REFERENCES
1. Singh BN, Nademanee K. Sotalol: a beta-blocker with unique antiarrhythmic properties. AM HEART J 1987;114:121-39. 2. Mehta A, Sanchez GR, Saks BJ, Casta A, Dunn JM, Donner RM. Ectopic automatic atria1 tachycardia in children: clinical characteristics, management and follow-up. J Am Co11 Cardiol 1988;11:379-85.
3. Bowman E, Paes BA, Way RC. Oral sotalol in neonatal supraventriculsr tachycardia. Acta Pediatr Stand 1988;77:171. 4. Koike K, Hesslein PS, Finlay CD, Williams WG, Izukawa T, Freedom RM. Atria1 automatic tachycardia in children. Am J Cardiol 1988;61:1127-30. 5. Gillette PC, Wampler DG, Garson A, Zinner A, Ott D, Cooley D. Treatment of atrial automatic tachycsrdia by ablation procedures. J Am Co11 Cardiol 1985;6:405-9. 6. Yabek SM, Kato R, Ikeda N, Singh BN. Cellular electrophysiologic responses of isolated neonatal and adult cardiac fibers to d-sotalol. J Am Co11 Cardiol 1988;11:1094-9.
