Atrial Flutter in the Neonate and Early Infancy

Transcription

1 Atrial Flutter in the Neonate and Early Infancy Chun-Chih PENG, MD, Ming-Ren CHEN, MD, Charles Jia-Yin HOU,1 MD, Han-Yang HUNG, MD, Hsin-An KAO, MD, Chyong-Hsin HSU, MD, and Fu-Yuan HUANG, MD SUMMARY Atrial flutter is a rare arrhythmia in the neonate and early infancy. We retrospectively reviewed the clinical presentations, treatment and outcome of seven patients who presented clinically with atrial flutter. The age of onset ranged from 1 day to 3 months. Atrial flutter was diagnosed in the first 3 days of life in 4. Three cases presented as atrial flutter with 2:1 atrioventricular conduction and the remaining 4 with variable AV block. Heart failure was present in 3 patients and 6 patients showed normal intracardiac structure on echocardiography. Electrical cardioversion was attempted as the first treatment in 4 cases, followed by digoxin in three of the four. Digoxin was given as an initial therapy in 2 patients. One patient recovered spontaneously without treatment. In the 6 patients who received therapy, 5 converted to normal sinus rhythm within 2 days. The remaining patient had ventricular ectopic beats for about 4 months. Only 2 cases were maintained on oral digoxin for at least 4 months after discharge. No patient had a recurrence of atrial flutter during the follow-up period which ranged from 6 months to 7 years. We conclude that there is a good long-term prognosis for atrial flutter in the neonate. Digoxin and DC cardioversion may be effective as initial therapy. Long-term digoxin prophylaxis after conversion to sinus rhythm may be not necessary. (Jpn Heart J 1998; 39: ) Key words: Atrial flutter, Neonate, Digoxin, Cardioversion TRIAL flutter is a rare arrhythmia in the newborn. Besides a large series of 25 cases reported by Casey et al.,1) we found only 6 to 10 patients described in the literature.2-7) Atrial flutter was classified into two groups according to the age of onset and the response to therapy.2,3) However some authors could not demonstrate a difference between these groups.4,5,6) Rodriguez-Coronel et al.2) classified atrial flutter in infancy into 2 types: Type 1 (congenital) atrial flutter From the Department of Pediatrics, 1Section of Cardiology, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan, ROC. Address for correspondence: Ming-Ren Chen, MD, Department of Pediatrics, Mackay Memorial Hospital, 92, Sec 2, Chung-Shan North Road, Taipei 104, Taiwan, ROC. Received for publication January 14, Accepted February 18,

2 288 PENG ET AL Jpn Heart J May 1998 which was present from birth, refractory to conversion by pharmacologic agents, but well tolerated and tended to become spontaneous conversion and type 2 (paroxysmal) atrial flutter which occurred paroxysmally several weeks or months after birth, was more likely to cause congestive heart failure and usually converted to sinus rhythm with medical therapy, but tended to recur afterwards. Moller et al.3) proposed a similar classification but noted that half of their patients with the "congenital" form responded to digoxin therapy. On the other hand, Rowland and coworkers4) concluded that separation of infants who had atrial flutter into congenital and paroxysmal types was superficial since the initiation of the arrhythmia may precede its detection by a considerable period. Mendelsohn et al.5) could not demonstrate any difference between those patients who were diagnosed with atrial flutter before birth, at birth, or later in the first year of life by either atrial flutter cycle length, response to therapy, or outcome. Casey et al.1) further concluded that neonatal atrial flutter had significant morbidity but an excellent long-term prognosis. The purpose of this retrospective report was to study the clinical course of atrial flutter in the neonate and early infancy, and try to identify optimal therapeutic options. METHODS We reviewed the medical records for all patients between 1984 and 1997 who presented with atrial flutter within the first 3 months of life. Diagnosis of atrial flutter was based on surface electrocardiographic findings of a typical flutter wave ("sawtooth" pattern). The prenatal/perinatal history and presentations, including age at diagnosis, symptoms, signs, electrocardiography, echocardiography, chest roentgenography, management and follow-up were analyzed. The loading dosage of digoxin used in our series was 0.03mg/kg. Directcurrent cardioversion used 0.5 to 1 Joule/kg. RESULTS Seven patients (2 girls and 5 boys) were included in the study. The clinical data are summarized in the Tables I `III. Clinical presentation Age at presentation. The diagnosis was made on the first day of life in 3 patients, on the 3rd day in 1 patient; and on days 28, 44 and 63 in the remaining 3 patients. Four patients was diagnosed in the first three days of life. No patient was noted to have atrial flutter in prenatal examinations (Table I). Birth history and symptoms. Only 1 patient was born prematurely (34 weeks gesta-

3 Vol 39 ATRIAL FLUTTER IN NEONATE AND INFANCY 289 No 3 Table I. Clinical Features BW=birth weight; C/S=Caesarean section; FT=full term; GA=gestational age; HF=sign of heart failure; NSD=vaginal delivery; PROM=premature rupture of the membranes. Table II. Patient Data AR=atrial rate; ASD=atrial septal defect; CK=creatine kinase; CK-MB=MB isoenzyme of CK; CXR=chest X-ray; MAS=meconium aspiration syndrome; PC=pulmonary congestion; U/l=unit per liter; VR=ventricular rate; WNL=within normal limits. tion). Patient 1 was born via cesarean section due to prolonged labor, preterm rupture of the membranes for 2 days and maternal pre-eclampsia. Patient 5 had meconium aspiration syndrome. The other patients had no perinatal complications. All patients were born outside our hospital. The clinical circumstances varied at the time when tachycardia was noted. Patients 1 and 4 had no symptoms and the tachyarrhythmia was found on routine examination. Patient 2 had poor activity on the first day of life with tachycardia and hepatomegaly noted. Patient 3 was referred to our hospital due to mild fever and arrhythmia. Patient 5 was noted to have tachycardia and tachypnea in the delivery room immediately after birth and was diagnosed with meconium aspiration syndrome. Patient 6 was brought to a local practitioner due to tachypnea and cyanosis at 44 days of age when tachycardia was found. He had cough and rhinorrhea 1 week prior to this episode. In patient 7, atrial flutter was

4 290 PENG ET AL Jpn Heart J May 1998 Figure 1. Lead II electrocardiography (ECG) from patient 5 demonstrated a classic atrial flutter wave with 2:1 atrioventricular block. The atrial rate was 428 beats per minute, and the ventricular rate was 214 beats per minute. Figure 2. Rhythm strip from patient 4 showed atrial flutter with variable atrioventricular conduction. Frequent VPCs were recorded. diagnosed immediately after bilateral herniorrhaphy. The patient had general anesthesia with halothane and nitrous oxide (N2O). Atropine had been administered during surgery. Electrocardiographic data (Table II). ECG rhythm strips in each infant demonstrated typical flutter waves ("sawtooth" pattern). The mean atrial rate was 391 (ranged 270 to 500) beats per minute while the mean ventricular rate was 164 (range 150 to 214) beats per minute. The atrioventricular conduction ratio was variable in 4 patients, and 2:1 AV block was recorded in 3 patients (Figure 1). In patient 4, frequent ventricular premature contractions were recorded (Figure 2). Echocardiography. Echocardiography was done in 6 of 7 patients and showed normal intracardiac structures in 4, and a small atrial septal defect (ASD) in 2 patients. The ASD closed spontaneously as shown by follow-up echocardiographic examination.

5 Vol 39 ATRIAL FLUTTER IN NEONATE AND INFANCY 291 No 3 Table III. Treatment, Follow-up and Outcome AF=atrial flutter; HF=sign of heart failure. Figure 3. Treatment and outcome in 7 patients. Other. Chest roentogenography revealed cardiomegaly in 2 patients. Creatine phosphokinase (CK) and its MB isoenzyme (CK-MB) were checked in 2 patients. No evidence of bacterial or viral infection was found in any patient. Treatment Initial treatment and response (Table III). In the initial treatment, conversion to normal sinus rhythm was achieved by digoxin in 2 patients, including 1 patient with heart failure. Cardioversion was used as the initial therapy in 4 patients, including 2 with heart failure, followed by digoxin in 3 of these 4. One patient had no treatment (patient 1) and the atrial flutter subsided after discharge; the duration of the arrhythmia from onset as well as the time conversion back to normal sinus rhythm remained unknown. Normal sinus rhythm occurred within 2 days in 5 out of 6 who received treatment. In patient 7, cardioversion was performed twice and was followed by digoxin injection. The duration of atrial flutter was 5 days in this patient. Long-term treatment and outcome (Figure 3). Two patients (patient 4 and patient 7)

6 292 PENG ET AL Jpn Heart J May 1998 had medication for 4 to 5 months after discharge. In patient 7, occasional ectopic ventricular premature contractions were recorded for about 4 months. No complications occurred during the therapeutic course except in patient 2, in whom digoxin was discontinued due to complete atrioventricular block despite a normal serum level (1.91ng/ml; normal range: 0.8 `2.0ng/ml). There was no recurrence of atrial flutter during follow-up which ranged from 0.5 to 7 years. (mean: 3.77 years) in any patient. DISCUSSION The present study has demonstrated that diagnosis of atrial flutter was usually evident from the surface electrocardiogram and most of the patients were rapidly diagnosed after delivery.1) Although fetal echocardiography is the most reliable method for the diagnosis of fetal arrhythmia,1,8,9) it usually requires a high level of expertise. Casey et al.1) reported neonatal atrial flutter had significant fetal and neonatal morbidity. In their series of 25 patients, 20 had fetal tachycardia; hydrops fetalis or heart failure presented at delivery in 12, no symptoms in 11 and the remaining 2 had nonspecific constitutional symptoms. The clinical severity in our series varied from no symptoms to mild cardiac decompensation, but there was no hydrops fetalis. Tachycardia was noted at delivery in only two patients, but we could not be sure whether they had preexisting tachycardia in utero. All of the patients were born in local clinics. None of our patients was diagnosed prenatally. The mechanism of atrial flutter in the newborn remains unknown. Pickoff et al.10) reported that the normal neonatal atrium is more susceptible to intraatrial reentry in response to premature extrastimulation than the more mature canine atrium. To date, research into the mechanism of atrial flutter has focused on reentry. Rowland et al.4) reported the etiology of atrial flutter was obscure in the majority of cases, although association with congenital heart diseases, indwelling atrial catheters, or cardiac surgery were reported as possible causes. In our study, there was no association with significant structural heart diseases. In patient 7, the atrial flutter was noted immediately after herniorrhaphy. General anesthesia was performed by inhalation of halothane and nitrous oxide (N2O). Halothane and N2O are popular and safe inhalation anesthetics in pediatric surgery. They have myocardial depressent effects and may slow sinoatrial node conduction. We could find no reports of atrial flutter resulting from anesthesia using halothane and N2O. In patients 2 and 5, elevations of CK/CK-MB and CK were found; myocarditis was suspected but not proved, because creatine kinase and isoenzyme levels might be normal in infants during the first 24 hours of life.11,12) The aim of pharmacologic therapy for atrial flutter is to slow the ventricular

7 Vol 39 No 3 ATRIAL FLUTTER IN NEONATE AND INFANCY 293 rate by increasing atrioventricular block.2-4,6) Rowland et al.4) indicated that the drug of choice for atrial flutter in infancy is digoxin, and direct current cardioversion should be reserved for critically ill patients. Martin et al.6) had similar conclusions and reported that digoxin therapy prior to DC cardioversion resulted in a better conversion rate and lower rate of recurrence. Dunnigan et al.7) reported that treatment with electrical conversion was usually sufficient and chronic pharmacological therapy was rarely necessary. Casey et al.1) showed that in the patients without evidence of severely compromised cardiovascular status, the choice of first-line therapy depended on institutional experience and expertise. In their series, digoxin was the first-line therapy and termination of atrial flutter occurred in only 33% of patients with digoxin alone. When a second treatment option was needed, direct-current cardioversion was better than propranolol and esophageal overdrive pacing. In contrast to Casey, response to digoxin therapy was good in four of our patients (atrial flutter was terminated in two patients with initial digoxin therapy). In the present series, we agreed that digoxin should be used first in asymptomatic atrial flutter and cardioversion should be used in symptomatic cases, although both digoxin and DC cardioversion were effective in patients with or without heart failure in our study. Electrical cardioversion can be performed more than once before stable sinus rhythm is achieved. On the other hand, digoxin may be used if rhythm does not convert to normal sinus rhythm after cardioversion. Drugs other than digoxin, such as quinidine,4) propranolol,6) and procainamide7) have been used, while amiodarone12) should be reserved for intractable, drug refractory atrial flutter in neonates. Atrial pacing or transesophageal overdrive pacing have been found to be effective treatments in some infants with atrial flutter,6,7) but they were not effective in Casey's series.1) In children, radiofrequency catheter ablation to cure cardiac arrhythmias, including atrial flutter, has shown good results,14) and this procedure was also used for intractable atrial flutter after Fontan procedure.15) But the risk of radiofrequency catheter ablation in patients under 2 years of age needs to be assessed.14) In our small series of patients, these all seemed unnecessary. Rowland4) recommended chronic digoxin therapy for one year after conversion, but others did not. The study of Mendelsohn et al.5) indicated no difference between patients treated for 6 months or longer with digoxin and those not so treated. Chronic digoxin therapy may be useful only for those patients with mixed flutter/fibrillation or other forms of supraventricular tachycardia.5) The recommendation by Casey et al.1) for continuation of treatment after hospital discharge is probably unnecessary in patients without evidence of preexcitation who are at risk for orthodromic atrioventricular reentry tachycardia. The optimal

8 294 PENG ET AL Jpn Heart J May 1998 duration of therapy and definitive efficacy of digoxin for atrial flutter prophylaxis in neonates have not been well established yet. Our study confirmed the good long-term prognosis for neonatal atrial flutter. There was no recurrence in any patient during follow-up. Spontaneous conversion is possible in some patients. On the other hand, the prognosis for a newborn with atrial flutter is poor if cardiac malformation or atrial fibrillation is present. A differential diagnosis between atrial flutter and atrial fibrillation, and further evaluation of the heart structure are thus important. Only 2 out of 7 patients had digoxin therapy for 4 to 5 months. Because of the narrow safety margin for digoxin and the good prognosis for atrial flutter, long-term digoxin therapy seems unnecessary after conversion to normal sinus rhythm. We conclude that the long-term prognosis for atrial flutter in the neonate is good. Digoxin and DC cardioversion may be effective as the initial therapy. Chronic digoxin therapy may not be necessary in most cases after conversion to normal sinus rhythm. Because of the low incidence of this arrhythmia in infancy, no prospective, randomized study comparing the therapeutic effects of different medications has been reported. Further trials are warranted in a larger number of patients to better delineate possible advantages and drawbacks between different treatment modalities, such as digoxin and cardioversion. REFERENCES 1. Casey FA, McCrindle BW, Hamilton RM, Gow RM. Neonatal atrial flutter: significant early morbidity and excellent long-term prognosis. Am Heart J 1997; 133: Rodriguez-Coronel A, Sueblingvong V, Hastreiter AR. Clinical forms of atrial flutter in infancy. J Pediatr 1969; 75: Moller JH, Davachi F, Anderson RC. Atrial flutter in infancy. Pediatrics 1969; 75: Rowland TW, Matthew R, Chameides L, Keane JF. Idiopathic atrial flutter in infancy: a review of eight cases. Pediatrics 1978; 61: Mendelsohn A, Dick II M, Serwer GA. Natural history of isolated atrial flutter in infancy. J Pediatr 1991; 3: Martin TC, Hernandez A. Atrial flutter in infancy. J Pediatr 1982; 100: Dunnigan A, Benson DW, Benditt DG. Atrial flutter in infancy: diagnosis, clinical features and treatment. Pediatrics 1985; 75: Allan LD, Anderson RH, Sullivan ID, Campbell S, Holt DW, Tynan M. Evaluation of fetal arrhythmias by echocardiography. Br Heart J 1983; 50: Kleinman CS, Donnerstein RL, Jaffe CC, et al. Fetal echocardiography: a tool for the evaluation of in utero cardiac arrythmias and the monitoring of in utero therapy: analysis of 71 patients. Am J Cardiol 1983; 51: Pickoff AS, Singh S, Flinn CJ, McCormack J, Stolfi A, Gelband H. Atrial vulnerability in the immature canine heart. Am J Cardiol 1985; 55: Jedeikin R, Makela SK, Shennan AT, Rowe RD, Ellis G. Creatine kinase isoenzymes in serum from cord blood and the blood of healthy term infants during the first three postnatal days. Clin Chem 1982; 28: Malamitsi-Puchner A, Minaretzis O, Maetzeli L, Papas C. Serum levels of creatine kinase and its isoenzymes during the first postpartum day in healthy newborns delivered vaginally or by Cesarean

9 Vol 39 ATRIAL FLUTTER IN NEONATE AND INFANCY 295 No 3 section. Gynecol Obstet Invest 1993; 36: Hijazi ZM, Rosenfeld LE, Copel JA, Kleinman CS. Amiodarone therapy of intractable atrial flutter in a premature hydropic neonate. Pediatr Cardiol 1992; 13: Van Hare GF, Witherell CL, Lesh MD. Follow-up of radiofrequency catheter ablation in children: results in 100 consecutive patients. J Am Coll Cardiol 1994; 23; Balaji S, Johnson TB, Sade RM, Case AL, Gillette PC. Management of atrial flutter after the Fontan procedure J Am Coll Cardiol 1994; 23: