Amiodarone and fetal supraventricular tachycardia. Apropos of a case with neonatal hypothyroidism]

BACKGROUND. Fetal tachycardia can be a cause of in utero death. Its detection is not always easy and its treatment is still controversial. CASE REPORT. Paroxysms of supraventricular tachycardia were detected on echocardiography at the 25th week of a second pregnancy. The mother was given sotalol, but the supraventricular tachycardia became permanent. At the 27th week of gestation, sotalol was stopped and the mother was given digoxin and the foetus received 2 injections of digoxin, 10 micrograms/kg, via the umbilical cord. As this treatment was only partially effective, the mother was also given amiodarone 800 mg/day at week 28, then the dose was reduced to 400 mg/day. However, at the 31st week, the mother showed signs of digoxin intolerance, and it was replaced by sotalol. Fetal blood tests at week 34 showed a high placental transfer of digoxin and sotalol and a low fetal level of amiodarone. The newborn, a girl, was born at the 36th week having a sinus rhythm. She developed signs of hypothyroidism (T4: 4 micrograms/ml; TSH:325 microliters U/ml at 5 days of life). CONCLUSION. The placental transfers of sotalol, digoxin and amiodarone are in the range of values known to be effective. The amiodarone responsible for hypothyroidism was given to the mother because she was intolerant to digoxin. Its use must be limited to arrhythmias that are resistant to other drugs or complicated by hydrops fetalis. When used, amiodarone should not be given for more than 6 weeks, and at the lowest possible dose.     

Sotalol in treatment of pediatric cardiac arrhythmias

BACKGROUND: There is limited experience on sotalol use in the management of childhood arrhythmias. This study reviews the results of our experience with oral sotalol for treatment and prevention of tachyarrhythmias in children. METHODS: The records of 62 patients (27 female, 35 male, mean age: 8.5+/-5.3 years) treated with sotalol for supraventricular or ventricular arrhythmias from 1994 to 1999 at our institution were reviewed. Demographic, clinical, echocardiographic, electrocardiographic (ECG), ambulatory ECG and electrophysiologic variables were collected. RESULTS: Forty-two (63.6%) patients had re-entrant supraventricular tachycardia, eight patients (12.9%) had atrial tachycardia, one patient (1.6%) had junctional ectopic tachycardia, four patients (6.5%) had ventricular tachycardia, and seven patients (11.3%) had complex ventricular arrhythmias, as evidenced by surface or ambulatory ECG records; or revealed during the electrophysiological study. The mean sotalol dose was 3.9+/-1.2 mg/kg per day. In 15.5+/-13.9 months of sotalol use 50% (n=31) had complete relief of symptoms and/or arrhythmia and 29% (n=18) had partial relief. Sotalol was ineffective in 20% (n=13). Sotalol was more effective in re-entrant type supraventricular tachycardias (P=0.012). Sotalol was the first choice in 35.5% of patients. The sotalol therapy was initiated in inpatient settings in 40.3% (25 patients). Complications due to sotalol were seen in six patients (five patients developed bradycardia/pauses, and one patient had torsades de pointes) for which the sotalol dose was modified. In patients with sick sinus syndrome, a pacemaker was implanted and in another patient sotalol was stopped. CONCLUSION: Sotalol, being an effective and safe drug particularly in children, is a good therapeutic alternative for the preventive treatment of childhood tachyarrhythmias.     

Second-Line Treatment of Fetal Supraventricular Tachycardia Using Flecainide Acetate

Digoxin has been an effective treatment for fetal supraventricular tachycardia (SVT), but second-line therapy remains more controversial. Thirty-seven cases of fetal SVT were identified that received digoxin as first-line therapy. Seventeen fetuses (46%) converted to and maintained normal sinus rhythm. Flecainide was used in 13/15 patients requiring second-line therapy; 12/13 (92%) converted to sinus rhythm. Of seven hydropic fetuses, five required second-line therapy and were then successfully converted with flecainide. The improved efficacy of flecainide was statistically significant with a p value <0.01. Complete follow-up was available in 13 digoxin-treated and in 12 second-line therapy infants. Prolonged or multiple drug therapy for postnatal arrhythmia management was required in 3/13 (23%) patients in the digoxin group and in 8/12 (67%) patients requiring second-line therapy. This demonstrated a correlation between the need for second-line fetal therapy and more complex postnatal management with a p value of 0.003. Digoxin remains an effective first-line therapy in the treatment of fetal SVT. Flecainide is an effective second-line therapy, especially in the face of fetal hydrops. Use of second-line therapy in fetal SVT is a predictor of complex postnatal course, and these patients should be followed more closely.     

Intrauterine conversion of fetal supraventricular tachycardia with combination of digoxin and verapamil

A case of fetal supraventricular tachycardia (SVT) diagnosed by fetal echocardiography at 31 weeks gestation and successfully converted in utero is reported. Administration of digoxin orally to the mother resulted in very brief periods of normal fetal cardiac rhythm. Intravenous administration of verapamil to the mother resulted in sustained conversion to normal fetal sinus rhythm. Maintenance therapy with oral digoxin and verapamil was given to the mother for the remainder of the pregnancy with no recurrence of the fetal arrhythmia.     

小儿室上性心动过速87例临床分析和治疗药物选择

目的探讨小儿室上性心动过速（SVT）诊断和分型中体表心电图的价值以及如何合理应用治疗SVT的药物。方法分析87例经过电生理检查的SVT患儿临床资料。结果89.7%的病例能通过体表心电图正确诊断及定位。SVT构成比为：房室折返性心动过速（AVRT）66.7%,房室结折返性心动过速（AVNRT）27.6%,其他5.7%。AVRT患儿应用普罗帕酮转复率为94.9%,维拉帕米为71.4%,ATP为75.0%,地高辛为62.5%;AVNRT用普罗帕酮转复率为83.3%,维拉帕米为90.0%,ATP为100.0%,地高辛为66.7%。药物不良反应发生率为：普罗帕酮14.8%,维拉帕米31.6%,ATP18.8%,地高辛18.2%。结论正确运用体表心电图诊断和定位以及药物治疗能有效地解决小儿SVT的诊疗问题,几种治疗SVT的药物对不同类型SVT的治疗价值各不相同,应用时应遵循一定的原则。     

Supraventricular tachycardia in the neonate and infant

Supraventricular tachycardia (SVT) is the most common sustained arrhythmia to present in the neonatal and infancy age group. Predisposing factors (congenital heart disease, drug administration, illness and fever) occur only in 15% of infants. The presentation of SVT in the neonate is frequently subtle, and may include pallor, cyanosis, restlessness, irritability, feeding difficulty, tachypnea, diaphoresis and grunting. Congestive heart failure is more common in infants under 4 months of age (35% incidence). Age-related differences in the distribution of SVT mechanisms occur in different age groups. In infants under 1 year of age, the mechanisms underlying SVT are atrial tachycardia (15%), AV nodal re-entry tachycardia (5%), and AV reciprocating tachycardia (80%). Options for acute management include: use of the diving reflex, intravenous adenosine, transesophageal pacing, and cardioversion. Intravenous administration of verapamil should be avoided. Data regarding freedom from recurrence of untreated SVT in the first year of life are limited, and may be in the range of 25-60%. Chronic therapy with digoxin, beta-blockers, flecainide, sotalol and amiodarone has proved effective in controlling recurrent episodes of SVT. Radiofrequency ablation can be employed successfully in medically refractory cases, but should be avoided in this age group (increased complication rate).     

Methemoglobinemia induced by refrigerated vegetable puree in conjunction with supraventricular tachycardia

We report on a case of methemoglobinemia in conjunction with supraventricular tachycardia. A 6-mo-old infant was admitted to hospital with perioral cyanosis three hours after eating a refrigerated mixed-vegetable puree. The patient developed supraventricular tachycardia (SVT) and had a heart rate of 230 beats/min. The arrhythmia resolved spontaneously. A chemical analysis showed oxygen saturation of 85% and a methemoglobin level of 25%. The infant was treated with oxygen and referred to the Pediatric Intensive Care Unit. The patient had two additional short episodes of SVT, which were resolved spontaneously without treatment. She received oxygen for 8 h until the methemoglobin level dropped to 1%. CONCLUSION: Long-term storage of refrigerated vegetables can cause methemoglobinemia in infants. Methemoglobinemia can appear in conjunction with SVT, but it is also possible that in a child with a tendency to develop SVT, methemoglobinemia involved hypoxemia, which then triggers SVT.     

High-Dose Sotalol Is Safe and Effective in Neonates and Infants With Refractory Supraventricular Tachyarrhythmias

Our objective was to assess the efficacy and safety of high-dose sotalol in neonates and infants with refractory supraventricular tachycardia (SVT). SVT in neonates and infants can be refractory to primary therapies; therefore, secondary agents, e.g., sotalol, are often required to obtain control of SVT. Age-factor nomogram dosing of sotalol is widely used; however, our institution uses greater doses based on body surface area (approximately 150–200 mg/m²/d). A retrospective review of 78 inpatients receiving sotalol, after failing another antiarrthymic medication, at our institution from 2001 to 2008 was performed. Corrected QT intervals (QTc), 24-h Holter–monitoring results, and outpatient records were reviewed to assess safety and efficacy for patients ≤2 years of age. Median patient age at the time of initiation of therapy was 24 days (range 3–728). Forty-eight patients (62%) were neonates, and 36 (46%) had congenital heart disease. The median sotalol dosage was 152 mg/m²/day (range 65–244). The SVT of 70 patients (90%) was controlled with sotalol. No patients experienced significant QTc prolongation or proarrhythmia. Mean duration of follow-up was 3.3 ± 0.24 years. High-dose sotalol allows for safe and rapid control of refractory tachyarrhythmias in this young age group.     

Re-entrant supraventricular tachycardia in infancy: current role of prophylactic digoxin treatment

Re-entrant supraventricular tachycardia is the most common cardiac arrhythmia in infancy. Pharmacological prevention of recurrencies is a standard recommendation for infants less than 1 year of age. In view of the often benign spontaneous clinical course of the disease, the risk-benefit analysis of any antiarrhythmic agent given is important. It was the aim of this retrospective study, to assess the value of oral long-term digoxin given to paediatric patients with supraventricular tachycardia with onset in the first 4 months of life. Twenty-six newborns and infants fulfilled the inclusion criteria. Median age at first presentation of the patients was 7 days. Eight patients (31%) had structural heart disease, 9 patients had a pre-excitation syndrome, and the other 17 children had a concealed accessory atrioventricular pathway. Long-term prophylaxis with oral digoxin was considered successful in 17 children (65%). In 2 patients therapy with digoxin was considered partially effective and in 7 patients (27%) failure of digoxin to improve symptoms led to the introduction of other anti-arrhythmic agents. Serum digoxin levels were no different in the patients with successful therapy as compared to those with treatment failure. No side-effects due to digoxin were noted in all the patients treated. After a mean followup of 54 months (12–130 months), 19 children (73%) were free of recurrencies and on no medication, 5 children were free of recurrencies but had anti-arrhythmic therapy. Only 2 patients, both on anti-arrhythmic therapy, were still suffering from tachycardia. Conclusion Digoxin remains an effective treatment option in infants with supraventricular tachycardia and it helped to avoid the long-term use of other anti-arrhythmic drugs with potentially more serious side-effects (pro-arrhythmia) in a considerable proportion of infants treated. Received: 29 April 1997 / Accepted in revised form: 31 July 1997     

Prediction of digoxin treatment failure in infants with supraventricular tachycardia: role of transesophageal pacing

Transesophageal atrial pacing was used to initiate and terminate tachycardia in 24 infants (seven female and 17 male, aged 1 to 34 days) with ECG documentation of supraventricular tachycardia. Six infants received no chronic treatment, and chronic oral digoxin prophylaxis was administered to 18 infants in an effort to prevent recurrences of tachycardia. In these 18 infants, the effectiveness of digoxin therapy in preventing the initiation of tachycardia by transesophageal pacing was compared with its ability to prevent spontaneous recurrences of supraventricular tachycardia. While receiving chronic oral digoxin therapy, tachycardia could be reinitiated in 15/18 (83%) infants. In these infants, the cycle length of tachycardia and the atrioventricular interval were the same before and during chronic digoxin treatment. Three infants in whom tachycardia could not be initiated during chronic digoxin therapy had no spontaneous recurrences during 6 months of follow-up, whereas 10/15 (67%) infants in whom tachycardia could be reinitiated had clinically significant recurrences in spite of chronic digoxin therapy. Six infants who received no chronic drug treatment had no documented recurrences during 6 months of follow-up. This study demonstrates that digoxin was effective in preventing significant spontaneous recurrences of supraventricular tachycardia in only 8/18 (44%) infants treated with digoxin. The ability to initiate supraventricular tachycardia with transesophageal pacing may be useful in determining which digoxin-treated infants are at risk for recurrence. Finally, not all infants with supraventricular tachycardia require chronic prophylaxis; six of the untreated infants had no documented recurrences.     

Prevalence of Arrhythmias and Their Risk Factors Mid- and Long-Term After the Arterial Switch Operation

Early results of the arterial switch operation (ASO) for transposition of the great arteries (TGA) are good, but there are few mid- and long-term data on postoperative arrhythmias, especially in Japan. In this study, clinical data on 624 1-year survivors who had an ASO between 1976 and 1995 were collected from six institutes in Japan up to October 2002. Sixty (9.6%) 1-year survivors had significant arrhythmias. Bradycardia occurred in 22 patients, including complete atrioventricular block (CAVB) in 12, sick sinus syndrome (SSS) in 6, and second-degree atrioventricular block in 4. Syncope developed in 2 with CAVB and 2 with SSS. Ten patients with bradycardia underwent permanent pacemaker implantation. Supraveutricular tachycardia (SVT) was seen in 25 patients, including paroxysmal supraventricular tachycardia in 16, atrial flutter in 7, and atrial fibrillation in 2. Six patients with SVT received antiarrhythmic medication. SVT was transient in 20 and persistent in 5. Ventricular arrhythmias occurred in 13 patients, including nonsustained ventricular tachycardia in 5, paroxysmal ventricular contractions with couplets in 5, ventricular flutter in 2, and sustained ventricular tachycardia in 1. Four patients with ventricular arrhythmias received antiarrhythmic medication. Of the study patients, 8 died 1 year or more after ASO. Death was directly related to arrhythmia in 1 patient and was due to nonsustained ventricular tachycardia with severe congestive heart failure. The presence of a ventricular septal defect (VSD) was a risk factor for postoperative arrhythmia. Patients with TGA and VSD had more arrhythmias than those with TGA and an intact ventricular septum (13.7 vs 8.7%, p < 0.05), and this was especially true for CAVB (3.9% vs 1.0%, p < 0.05). In 36 patients clearly documented time onset of postoperative arrhythmia arrhythmia developed in 18 (50%) after less than 1 year and in 15 (42%) after more than 5 years. In summary serious arrhythmias after ASO were uncommon, but postoperative arrhythmias, such as unpaced CAVB, SSS, and VT, were related to morbidity and mortality. VSD was a risk factor for postoperative arrhythmia, especially CAVB. Approximately half of the arrhythmias developed late. Lifelong monitoring with respect to arrhythmia is needed for patients after ASO.     

食管心房调搏在小儿心动过速中的应用

目的探讨食管电生理检查对小儿心动过速的诊断、分型和终止发作的临床意义。方法采用食管心房调搏技术对３２例小儿快速心律失常进行分型诊断及转复治疗。结果心动过速３２例中体表心电图表现为室上性心动过速（室上速）２７例：其中房室折返性心动过速１５例,房室结折返...     

A Multi-institutional Analysis of Inpatient Treatment for Supraventricular Tachycardia in Newborns and Infants

This study aimed to examine practice patterns in the inpatient medical treatment of newborns and infants with supraventricular tachycardia (SVT) using the Pediatric Health Information System (PHIS) database, a large, multi-institutional administrative database. A retrospective examination of pediatric hospital discharge data was performed during the study period from January 2003 to September 2008. Data were extracted from the index hospitalization of all individuals younger than 1 year with the principal discharge diagnosis of SVT. Those with coexisting congenital or acquired structural heart disease were excluded from the study. The analysis included 171 patients. No deaths occurred, and 95 % of the infants were discharged to home. More than half (53 %) of the patients spent a portion of their hospital stay in an intensive care unit (ICU) setting. Multidrug therapy was common, with 45 % of the patients receiving two or more antiarrhythmic agents on the day of discharge. The five most commonly used antiarrhythmic drugs, in order of decreasing frequency of use, were propranolol, digoxin, amiodarone, flecainide, and sotalol. The median hospital stay for the group was 4 days, and this value increased as a function of the number of antiarrhythmic drugs used (median, 7 days for three or more agents) and the need for intensive care (median, 6 days). The information provided in this study helps to define common practice patterns and should allow caregivers to provide meaningful expectations to families regarding their potential treatment course and to anticipate the hospital length of stay.     

胎儿先天性心脏病和心律失常的诊断及干预

目的 研究胎儿超声心动图产前诊断先天性心脏病（简称先心病）和经胎盘治疗胎儿心律失常的价值。方法 应用国产FECG－D型胎儿心电图仪筛查,结合胎儿超声心动图检测第1胎患先心病的460例胎龄为18－40周的高危胎儿,超声仪采用ALT、Maker LX和TOSHBA SSA 40A多普勒彩色超声仪,探头频率为3．5MHz。结果 发现先心病8例,同胞一级亲属患病率为1．7％。先心病的类型：房间隔缺损（简称房缺）3例（其中1例合并胎儿水肿）,室间隔缺损（简称室缺）13例（其中1例合并神经管缺损）,完全性的房室管缺损1例,法洛四联症1例。检出23例胎儿心律失常,检出率为5．0％,以室上性心动过速（简称室上速）最多见（13例）,首选地高辛经胎盘治疗,7例有效,其中3例合并先心病或心力衰竭者加用异博定2例有效,1例因有严重的非免疫性胎儿水肿而死亡;3例窦性心运过速（简称窦速）患儿用心得安治疗有效,1例频发室性早博用普鲁卡因酰胺治疗后转复。3例妊娠晚期的室上速和2例室上性早博未用药,经阴道分娩后转复。结论 胎儿超声心动图是产前诊断胎儿心脏异常的重要手段,地高辛是经胎盘治疗胎儿快速心律失常的首选药物。     

Impact of Transesophageal Electrophysiologic Study to Elucidate the Mechanism of Arrhythmia on Children With Supraventricular Tachycardia and No Preexcitation

An electrophysiologic study (EPS) of children and teenagers with paroxysmal supraventricular tachycardia (SVT) and normal electrocardiography (ECG) in sinus rhythm was evaluated. Generally, EPS is performed only before paroxysmal SVT ablation in these patients. In this study, 140 patients (mean age, 15 ± 3 years) with normal ECG in sinus rhythm were studied for SVT by a transesophageal route in baseline state and after isoproterenol. Idiopathic left or right ventricular tachycardia was diagnosed in four patients (3 %). Anterograde conduction over an atrioventricular (AV) left lateral (n = 10) or septal (n = 9) accessory pathway (AP) was noted in 19 patients (13.5 %) at atrial pacing. Orthodromic AV reentrant tachycardia (AVRT) was induced in these children. Five of the patients had a high rate conducted over AP (>240 bpm in baseline state or >290 bpm after isoproterenol). Two of the patients (a 10-year-old girl with well-tolerated SVT and a 17-year-old with syncope-related SVT) had the criteria for a malignant form with the induction of atrial fibrillation conducted over AP at a rate exceeding 290 bpm in baseline state. Of the 140 patients, 74 (53 %) had typical AV node reentrant tachycardia (AVNRT), nine had atypical AVNRT (6 %), 1 had atrial tachycardia (0.7 %), and 33 (23.5 %) had AVRT related to a concealed AP with only retrograde conduction. Electrophysiologic study is recommended for children with paroxysmal SVT and normal ECG in sinus rhythm. The data are helpful for guiding the treatment. Ventricular tachycardia or atrial tachycardia can be misdiagnosed. Masked preexcitation syndrome with anterograde conduction through AP was present in 13.5 % of the patients, and 1.4 % had a malignant preexcitation syndrome.     

Recommendations for the treatment of recurrent supraventricular tachycardia in infants]

AIM: The effectiveness and safety of antiarrhythmic agents, mostly digoxin and amiodarone given to prevent recurrences, were compared in 141 infants of less than 1 year (77% < 1 month) with re-entrant supraventricular tachycardia. RESULTS: Digoxin was the drug of first choice in 114 patients at a dose of 10-20 micrograms/kg/d and was effective in 74 cases (65%). Amiodarone was used as first line therapy or after failure of digoxin. It was given at a maintenance dose of 250 mg/m2/d, alone in 22 infants and together with digoxin in another 36; it was effective in 56 cases (96.5%). Early adverse events occurred in six patients receiving digoxin: ventricular fibrillation requiring cardioversion in three, two of whom had Wolff-Parkinson-White syndrome, significant sinus bradycardia in two, accidental overload in one. At further follow-up, one child treated with digoxin but having also gastroesophageal reflux, died suddenly at 3 months of age; autopsy was normal and the digoxin blood level was 3 ng/mL. Among the 58 infants who received amiodarone, there were no proarrhythmia, a slight and transient increase in TSH in six infants and only one required a short-term treatment for hypothyroidism. Prophylactic therapy was maintained for 6 to 12 months and only ten patients had recurrences in the year following withdrawal. CONCLUSION: Amiodarone was found to be safer and more effective than digoxin. No significant side-effect was demonstrated in infants receiving a short-term treatment. Amiodarone may be proposed as first line therapy for prophylaxis of re-entrant supraventricular tachycardia in infancy, especially for those patients with reentry and Wolff-Parkinson-White syndrome.     

Idiopathic atrial flutter in infancy: a review of eight cases.

The experience of three institutions in the management of atrial flutter in infants under 2 years of age without associated heart disease is reviewed. Five babies with neonatal onset were treated with digoxin and had uncomplicated resolution of their arrhythmia, although one continued to have episodes of paroxysmal supraventricular tachycardia for six years. Two of the three older infants required DC cardioversion for complications after quinidine was substituted for digoxin therapy. Digoxin continues to be the preferred initial therapy for non-acutely ill patients; those showing signs of cardiac decompensation should be converted with DC countershock.     

Intrauterine supraventricular tachyarrhythmias and transplacental digitalisation.

Six newborn infants with intrauterine supraventricular tachyarrhythmias (five cases of atrial flutter and one of supraventricular tachycardia) are described. Transplacental digitalisation was attempted in three cases. Supraventricular tachycardia associated with hydrops fetalis, detected in a fetus at a gestation of 31 weeks, was successfully converted to normal sinus rhythm eight days after the mother began treatment with digoxin. The serum concentration of digoxin in cord blood almost equalled the maternal concentration in three cases. In the remaining three cases treatment with digitalis was effective in converting tachyarrhythmias to sinus rhythm after delivery. With maintenance digoxin therapy, the prognosis of fetal tachyarrhythmias seems to be good, once conversion to sinus rhythm has been accomplished.     

The treatment of arrhythmias in infants and children using propafenone

Antiarrhythmic treatment was required in 35 patients aged one day to 11 8/12 years (average 5 7/12 years) for one or several of the following arrhythmias: paroxysmal supraventricular tachycardia (17), ventricular extrasystole (16), ventricular tachycardia (17), ventricular extrasystole (16), ventricular tachycardia (4), junctional tachycardia (4), and atrial flutter (3). 300 mg/m2/day oral propafenone was administered in 3 to 4 divided doses. The arrhythmia in 21 of the 35 patients had been unsuccessfully treated by digoxin (6), verapamil (5), ajmalin (4), propranolol (3), spartein (1), phenytoin (1), and lidocain (1) prior to the propafenone therapy. However, the arrhythmias could be abolished or reduced in 30 patients (85.7%) by Propafenone. In 5 patients with supraventricular tachycardia (2), junctional tachycardia (2), or ventricular extrasystole (1), propafenone therapy had no effect. In two other patients propafenone led to atrioventricular conduction disturbances and had to be discontinued. Propafenone is an effective well tolerated antiarrhythmic drug without major side effects in pediatric patients.     

CHRONIC SUPRAVENTRICULAR TACHYCARDIA IN INFANCY AND CHILDHOOD

ABSTRACT: Jacobsen, J. R., Andersen, E. D., Sandøe, E., Videbeek, J. and Wennevold, A. (Medical Department B and Department of Paediatrics, Rigshospitalet, Queen Louise's Hospital for Children, Copenhagen, and Departments of Cardiology and Paediatrics, århus Kommunehospital, århus, Denmark). Chronic supraventricular tachycardia in infancy and childhood. Acta Paediatr Scand, 64:597, 1975.–The results of a one to 19 year follow-up study of 9 children with supraventricular tachycardia of more than one month's duration are reported. The ECG diagnosis of tachycardia was made before birth in one patient and between the ages of 8 months and 12 years in 8. Four had sustained and 4 had repetitive tachycardia, while one patient had both patterns at different times. Reciprocal rhythm was diagnosed in 3 patients and exit block in 2. Severe symptoms had occurred in 2 patients, but as a rule symptoms were mild or absent. No treatment abolished the arrhythmias but digitalis reduced the overall ventricular rate in 6 patients. After a duration of 1–7 years, 3 patients still had tachycardia at the follow-up. In the remaining 6 patients the tachycardia had subsided 7 months to 10 years after the onset.