Efficacy and Safety of Propafenone in Congenital Junctional Ectopic Tachycardia THOMAS
PAUL,
HANS-CARLO .%““rr”Pr.
MD. ANNETTE KALLFELZ,
REIMER.
MD, JAN JANOUSEK,
MD,*
MD
Cwnany rrnd Pr~:I,P, Czrck~&wK,lI
Objectives.Class IC antiarrhythmir dru8s have recently been shnwn to be eiiectivc in some padentSwith strial tiopic tachycxdia. We thereforestudied dte oiftcacyof thosedrugs in p&w with congnitat junctional ectopictarhyeardta. Bmkground. Eollaw-up data on patients with junctiinal ectopic tachycardia suggestthat this potentially lethal arrhythmia may ceasespantanoouslyin a signififiant proportion of aReted children. Therefore, temporary nntiarrhylhmic trealment ap pearsto be the therapy of choice.
The diagnosis of junctional ectopic tachycardia can be established bv exilmination of the surface electrocardiwam (ECG). This iare and untque type of t&hycardia is defined as a tachvcardia with a narmw OK.5 complex configuration and a~tioventricular (AV) diss&tion (1.2). Its electrophysiologic mechanism is an abnormally enhanced automalicity within the His bundle. Because the tachyarrhythmia is present >!X% of the time. it is classified as an incessant form of tachycardia. Its prognosis is poor. particularly in young children (I+6). Secondary dilated cardiomyopathy. ventricular fibrillation and sudden cardiac death have been reported (i.2.4,7-9). Automatic tachycardias are more resistant to medical treatment than are reenWant tachycardias (IO). In a recent multicenter study (9) involving 26 infants with congenital junctional ectapic tachycardia, amiodarone was found to be the most effective drug for this arrhythmia, and His bundle ablation was recommended for patients with tachycardia resistant to drug treatment. Amiodamne, however. has several significant physical and ekctmphysiologic side effects (I I).
supnventricular
Class IC drugs, such as encainide and kainide. have been shown to be effective in the treatment of chronic atria1 ectopic tachycardia (12). In postsurgical junctional ectopic tachycardia. prop&none, another class IC agent, has been demonstmted to be useful (13). In a previous study from our institution (14). we found pmpafenone to be effective in the management of supraventricular tachycardia caused by ectopic foci. However. pmpafenone and other class IC drugs were only infrequently used in the multicenter trial cited (9). Therefore the purpose of the present study was to evaluate the efikacy and safety of prop&none in patients with congenital junctional ectopic tachycardia.
MdhOd.9 Patient cbsrrteristia. Between 1987and 1991, four infants with congenital junctional ectopic tachycardia were admitted to our institution. The mean age at diagnosis was 1.1 months (range 0.1 to 2). The mean vcnrricular rate was 224 beatsimin (range I80 to 320). None of the four infants had a family history ofjunctional ectopic tachycxdia. BIectrwrdioBpphic dispoosis. The diagnosis of junctional ectopic rachycardia was made in each patient by surface ECG according to well established criteria (1,9). Administration al pmp&ootte. The drug was administered as pellets containing 10mgof prop&none and according to our recently published protocol (14). This registered preparation of pmpafenone was approved for use in pediat-
ric patients by the Federal Drug Administration (Bundesge&ndheitsamt) of the Federal Republic of Germany in 1985. Propafenone in IO-mg pellets was supplied by KIWII AC. The study protocol was appmved by the scientific committee of the Children’s Hospital of Hannover Medical School. Written informed consent u’as obtained from the parents of each of the patients. Treatment began with three oral doses of 100 mg of propafenone/m* body surface area pa day, given for at least 3 days. Patients were monitored with continuous Halter recordings and daily IS-lead ECGs during the 1st days of propafenone therapy. If the arrhythmia persisted, the dosage was increased to “11to My) meIn? per day in 100me/m2 steps in 3.day intervals.’ treatment. Treatment was considered completely effective if the tachycardia was lotally suppressed on Halter recordings and arrhythmia-related symptoms disappeared. Partial snccesswas detised as a decreasein the rate of the tachycardia to
PAUL,
HANS-CARLO .%““rr”Pr.
MD. ANNETTE KALLFELZ,
REIMER.
MD, JAN JANOUSEK,
MD,*
MD
Cwnany rrnd Pr~:I,P, Czrck~&wK,lI
Objectives.Class IC antiarrhythmir dru8s have recently been shnwn to be eiiectivc in some padentSwith strial tiopic tachycxdia. We thereforestudied dte oiftcacyof thosedrugs in p&w with congnitat junctional ectopictarhyeardta. Bmkground. Eollaw-up data on patients with junctiinal ectopic tachycardia suggestthat this potentially lethal arrhythmia may ceasespantanoouslyin a signififiant proportion of aReted children. Therefore, temporary nntiarrhylhmic trealment ap pearsto be the therapy of choice.
The diagnosis of junctional ectopic tachycardia can be established bv exilmination of the surface electrocardiwam (ECG). This iare and untque type of t&hycardia is defined as a tachvcardia with a narmw OK.5 complex configuration and a~tioventricular (AV) diss&tion (1.2). Its electrophysiologic mechanism is an abnormally enhanced automalicity within the His bundle. Because the tachyarrhythmia is present >!X% of the time. it is classified as an incessant form of tachycardia. Its prognosis is poor. particularly in young children (I+6). Secondary dilated cardiomyopathy. ventricular fibrillation and sudden cardiac death have been reported (i.2.4,7-9). Automatic tachycardias are more resistant to medical treatment than are reenWant tachycardias (IO). In a recent multicenter study (9) involving 26 infants with congenital junctional ectapic tachycardia, amiodarone was found to be the most effective drug for this arrhythmia, and His bundle ablation was recommended for patients with tachycardia resistant to drug treatment. Amiodamne, however. has several significant physical and ekctmphysiologic side effects (I I).
supnventricular
Class IC drugs, such as encainide and kainide. have been shown to be effective in the treatment of chronic atria1 ectopic tachycardia (12). In postsurgical junctional ectopic tachycardia. prop&none, another class IC agent, has been demonstmted to be useful (13). In a previous study from our institution (14). we found pmpafenone to be effective in the management of supraventricular tachycardia caused by ectopic foci. However. pmpafenone and other class IC drugs were only infrequently used in the multicenter trial cited (9). Therefore the purpose of the present study was to evaluate the efikacy and safety of prop&none in patients with congenital junctional ectopic tachycardia.
MdhOd.9 Patient cbsrrteristia. Between 1987and 1991, four infants with congenital junctional ectopic tachycardia were admitted to our institution. The mean age at diagnosis was 1.1 months (range 0.1 to 2). The mean vcnrricular rate was 224 beatsimin (range I80 to 320). None of the four infants had a family history ofjunctional ectopic tachycxdia. BIectrwrdioBpphic dispoosis. The diagnosis of junctional ectopic rachycardia was made in each patient by surface ECG according to well established criteria (1,9). Administration al pmp&ootte. The drug was administered as pellets containing 10mgof prop&none and according to our recently published protocol (14). This registered preparation of pmpafenone was approved for use in pediat-
ric patients by the Federal Drug Administration (Bundesge&ndheitsamt) of the Federal Republic of Germany in 1985. Propafenone in IO-mg pellets was supplied by KIWII AC. The study protocol was appmved by the scientific committee of the Children’s Hospital of Hannover Medical School. Written informed consent u’as obtained from the parents of each of the patients. Treatment began with three oral doses of 100 mg of propafenone/m* body surface area pa day, given for at least 3 days. Patients were monitored with continuous Halter recordings and daily IS-lead ECGs during the 1st days of propafenone therapy. If the arrhythmia persisted, the dosage was increased to “11to My) meIn? per day in 100me/m2 steps in 3.day intervals.’ treatment. Treatment was considered completely effective if the tachycardia was lotally suppressed on Halter recordings and arrhythmia-related symptoms disappeared. Partial snccesswas detised as a decreasein the rate of the tachycardia to
