Early and late arrhythmias after the Fontan operation: predisposing factors and clinical consequences.

OBJECTIVE--To study the incidence, predisposing factors, and clinical significance of arrhythmias early and late after the Fontan operation for congenital heart disease. PATIENTS AND METHODS--All 104 consecutive patients undergoing Fontan repair from 1975 to 1988 were studied retrospectively. Hospital records were reviewed for perioperative arrhythmia. Clinical information and annual electrocardiograms were available for all 78 hospital survivors during a follow up of up to 13 years (mean 3.7 years). Ambulatory electrocardiographic monitoring was performed in 67 patients (81%). RESULTS--Eleven patients (10.6%) developed a perioperative tachycardia (eight, atrial flutter; three, His bundle tachycardia). Multivariate analysis showed that raised preoperative mean pulmonary artery pressure and low aortic saturation were significant risk factors for the development of atrial flutter (r2 = 0.32, p = 0.0001) but not for His bundle tachycardia. Despite intensive medical treatment 10 of these 11 patients died. At the last visit 72 (92%) of the 78 patients were in sinus rhythm on their standard 12 lead electrocardiogram. Junctional rhythm was present in three patients, two patients had atrial flutter, and one had a paced rhythm. Ambulatory monitoring did not show important bradycardia or ventricular arrhythmias. Actuarial survival free of supraventricular arrhythmia was 82% at eight years after operation. Multivariate analysis identified older age, increased right atrial size, and raised mean preoperative pulmonary artery pressure as risk factors for arrhythmia during intermediate follow-up (r2 = 0.46, p less than 0.001). Late tachycardias, in contrast to those occurring in the perioperative period, were not associated with an increased mortality. CONCLUSIONS--Except for his bundle tachycardia in the perioperative period, early and late arrhythmias after a Fontan operation seem to be a consequence of adverse preoperative and postoperative haemodynamic function. The perioperative outcome is therefore poor even when the patient can be restored to sinus rhythm. Medical and surgical modifications to improve the haemodynamic disturbances associated with arrhythmias are therefore indicated.     

Arrhythmias after the Fontan procedure.

OBJECTIVE--To study the determinants and outcome of arrhythmias after the Fontan type operation. DESIGN--Retrospective analysis of data in patients operated on between 1972 and 1986 (follow up 5-19 years (mean 12 years)). PATIENTS--All 60 patients undergoing a Fontan type procedure at the National Heart Hospital, London, during the study period (mean age (SD) 12.3 (6.8) years). RESULTS--Postoperative arrhythmias occurred in 34 patients (57%), and 11 (58%) of 19 early postoperative deaths (within seven days) were related to arrhythmias. Early arrhythmias occurred in 19 (32%) patients of whom 11 (58%) died. All patients with early atrial fibrillation and His bundle tachycardia died and only preoperative atrial fibrillation recurred early. There was a higher incidence of early arrhythmias, which were less well tolerated, in double inlet single ventricle patients (9/19) than in those with tricuspid atresia (8/37). There were no other preoperative determinants of early arrhythmias or deaths from early arrhythmia. Late (after seven days) arrhythmias occurred in 15 (37% of hospital survivors). They had higher right atrial (RA) pressures both early and late after operation and had lower ventricular ejection fractions late after operation. Of those with atrial arrhythmias 86% had RA obstruction and 57% had an RA thrombus or pulmonary embolism at presentation; this was also confirmed in two patients in whom late sudden deaths occurred. Atrial fibrillation early after reoperation for RA obstruction was fatal. The actuarial arrhythmia free survival for hospital survivors was 60% at 10 years. CONCLUSIONS--Early postoperative arrhythmias were poorly tolerated, particularly atrial fibrillation and His bundle tachycardia. Previous atrial fibrillation was a relative contraindication to this procedure. Late postoperative arrhythmias were associated with higher RA pressures measured both early and late after operation and worse late ventricular function. Late arrhythmias may be the first manifestation of RA obstruction, which must be sought. RA thrombus was common in patients with atrial arrhythmias and should be treated early with anticoagulants.     

Moderate hypothermia in the management of resistant automatic tachycardias in children.

BACKGROUND--Automatic focus tachycardias are often resistant to electrical and pharmacological treatment. Moderate systemic hypothermia (32-34 degrees C) may reduce the tachycardia rate in children with His bundle tachycardia after cardiac surgery. METHODS--The case notes of seven children with automatic focus tachycardias treated with hypothermia were reviewed. Six had His bundle tachycardia after cardiac surgery and one had ectopic atrial tachycardia; all had signs of low cardiac output. RESULTS--Hypothermia led to a reduction in heart rate in all patients (from 211 (28) (mean (SD] to 146 (5) beats/minute, p less than 0.001), with rises in systolic blood pressure (from 74 (14) mm Hg to 97 (10) mm Hg, p less than 0.01) and hourly urine output (from 0.5 (0.4) ml/kg to 4.6 (2.8) ml/kg, p less than 0.02). No direct adverse effects were noted. The arrhythmia did not resolve in three children, who died (two with His bundle tachycardia after Fontan procedures and one with ectopic atrial tachycardia); the other four regained sinus rhythm which was maintained at follow up of 3-13 (mean 9) months. CONCLUSIONS--Moderate systemic hypothermia led to slowing of the arrhythmia rate and an improvement in cardiac output in patients with resistant automatic focus tachycardias. It can be used to improve the haemodynamic condition while other measures of arrhythmia control are being pursued or until spontaneous recovery of normal rhythm.     

Moderate hypothermia in the management of resistant automatic tachycardias in children

BACKGROUND--Automatic focus tachycardias are often resistant to electrical and pharmacological treatment. Moderate systemic hypothermia (32-34 degrees C) may reduce the tachycardia rate in children with His bundle tachycardia after cardiac surgery. METHODS--The case notes of seven children with automatic focus tachycardias treated with hypothermia were reviewed. Six had His bundle tachycardia after cardiac surgery and one had ectopic atrial tachycardia; all had signs of low cardiac output. RESULTS--Hypothermia led to a reduction in heart rate in all patients (from 211 (28) (mean (SD] to 146 (5) beats/minute, p less than 0.001), with rises in systolic blood pressure (from 74 (14) mm Hg to 97 (10) mm Hg, p less than 0.01) and hourly urine output (from 0.5 (0.4) ml/kg to 4.6 (2.8) ml/kg, p less than 0.02). No direct adverse effects were noted. The arrhythmia did not resolve in three children, who died (two with His bundle tachycardia after Fontan procedures and one with ectopic atrial tachycardia); the other four regained sinus rhythm which was maintained at follow up of 3-13 (mean 9) months. CONCLUSIONS--Moderate systemic hypothermia led to slowing of the arrhythmia rate and an improvement in cardiac output in patients with resistant automatic focus tachycardias. It can be used to improve the haemodynamic condition while other measures of arrhythmia control are being pursued or until spontaneous recovery of normal rhythm.     

Atrial pacing as an adjunct to the management of post-surgical His bundle tachycardia.

OBJECTIVE--To examine the benefits of restoring atrioventricular synchrony to children with His bundle tachycardia after operation for congenital heart disease. DESIGN--Review of clinical outcome of adopting the technique of R wave synchronised atrial pacing as an adjunct to the management of His bundle tachycardia from September of 1987 till June of 1990. PATIENTS--Eleven consecutive children (aged between 3 days and 13 years) with haemodynamically significant His bundle tachycardia after cardiopulmonary bypass surgery. INTERVENTIONS--Atrial pacing synchronised either manually or automatically to the R wave of the His bundle tachycardia was implemented so that atrial depolarisation preceded the following R wave by an appropriate PR interval. RESULTS--An immediate and sustained increase in mean systemic blood pressure (average 15 mm Hg, range 6-30 mm Hg) was seen with the onset of atrial pacing in 10 of the 11 children. One child, who had undergone a Fontan procedure, developed atrial flutter shortly after the onset of atrial pacing and required direct current cardioversion. Four children died. Of the seven survivors, six have sustained sinus rhythm which returned between two and 10 days after the onset of tachycardia. One of the survivors has severe neurological impairment attributed to a period of low cardiac output during tachycardia; the others are alive and well. In those children who did badly the mean time between arrhythmia occurrence and the start of atrial pacing or cooling or both was nine hours; in those who did well it was one hour. CONCLUSIONS--Atrial pacing synchronous with the His bundle is a useful adjunct in the management of children with His bundle tachycardia after surgery for congenital cardiac disease.     

Atrial pacing as an adjunct to the management of post-surgical His bundle tachycardia

OBJECTIVE--To examine the benefits of restoring atrioventricular synchrony to children with His bundle tachycardia after operation for congenital heart disease. DESIGN--Review of clinical outcome of adopting the technique of R wave synchronised atrial pacing as an adjunct to the management of His bundle tachycardia from September of 1987 till June of 1990. PATIENTS--Eleven consecutive children (aged between 3 days and 13 years) with haemodynamically significant His bundle tachycardia after cardiopulmonary bypass surgery. INTERVENTIONS--Atrial pacing synchronised either manually or automatically to the R wave of the His bundle tachycardia was implemented so that atrial depolarisation preceded the following R wave by an appropriate PR interval. RESULTS--An immediate and sustained increase in mean systemic blood pressure (average 15 mm Hg, range 6-30 mm Hg) was seen with the onset of atrial pacing in 10 of the 11 children. One child, who had undergone a Fontan procedure, developed atrial flutter shortly after the onset of atrial pacing and required direct current cardioversion. Four children died. Of the seven survivors, six have sustained sinus rhythm which returned between two and 10 days after the onset of tachycardia. One of the survivors has severe neurological impairment attributed to a period of low cardiac output during tachycardia; the others are alive and well. In those children who did badly the mean time between arrhythmia occurrence and the start of atrial pacing or cooling or both was nine hours; in those who did well it was one hour. CONCLUSIONS--Atrial pacing synchronous with the His bundle is a useful adjunct in the management of children with His bundle tachycardia after surgery for congenital cardiac disease.     

Cardiac arrhythmias in patients with surgical repair of Ebstein's anomaly

Preoperative, perioperative and postoperative arrhythmias in 52 consecutive patients who underwent operation for Ebstein's anomaly were reviewed. There were 25 male and 27 female patients (mean age 18 years, range 11 months to 64 years). Thirty-four patients had one or more documented arrhythmias preoperatively (18 had paroxysmal supraventricular tachycardia, 10 had paroxysmal atrial fibrillation or flutter, 13 had ventricular arrhythmia and 3 had high grade atrioventricular block). Seven patients without documented arrhythmias had a history typical of tachyarrhythmias. During the perioperative and early postoperative periods, 14 patients had atrial tachyarrhythmias and 8 had ventricular tachycardia or ventricular fibrillation. There were seven deaths between day 1 and 27 months after operation. Five of these deaths were sudden (all in male patients, aged 12 to 34 years), and four of the patients had had perioperative ventricular tachycardia or ventricular fibrillation. One patient was taking one antiarrhythmic agent and another patient was taking two at the time of sudden death. Of the 18 patients with paroxysmal supraventricular tachycardia and 9 patients with paroxysmal atrial fibrillation or flutter preoperatively who were followed up for a mean of 40 and 36 months, respectively, 22 and 33% continued to have symptomatic tachycardia. Of the 11 patients (mean age 9 years) without preoperative documentation or symptoms of arrhythmia, follow-up data were obtained (range 1 to 144 months, mean 31) in 9 patients. None died suddenly or developed symptomatic arrhythmia.     

Arrhythmias after the Fontan procedure

Objective—To study the determinants and outcome of arrhythmias after the Fontan type operation.Design—Retrospective analysis of data in patients operated on between 1972 and 1986 (follow up 5–19 years (mean 12 years)).Patients—All 60 patients undergoing a Fontan type procedure at the National Heart Hospital, London, during the study period (mean age (SD) 12·3 (6·8) years).Results—Postoperative arrhythmias occurred in 34 patients (57%), and 11 (58%) of 19 early postoperative deaths (within seven days) were related to arrhythmias. Early arrhythmias occurred in 19 (32%) patients of whom 11 (58%) died. All patients with early atrial fibrillation and His bundle tachycardia died and only preoperative atrial fibrillation recurred early. There was a higher incidence of early arrhythmias, which were less well tolerated, in double inlet single ventricle patients (9/19) than in those with tricuspid atresia (8/37). There were no other preoperative determinants of early arrhythmias or deaths from early arrhythmia. Late (after seven days) arrhythmias occurred in 15 (37% of hospital survivors). They had higher right atrial (RA) pressures both early and late after operation and had lower ventricular ejection fractions late after operation. Of those with atrial arrhythmias 86% had RA obstruction and 57% had an RA thrombus or pulmonary embolism at presentation; this was also confirmed in two patients in whom late sudden deaths occurred. Atrial fibrillation early after reoperation for RA obstruction was fatal. The actuarial arrhythmia free survival for hospital survivors was 60% at 10 years.Conclusions—Early postoperative arrhythmias were poorly tolerated, particularly atrial fibrillation and His bundle tachycardia. Previous atrial fibrillation was a relative contraindication to this procedure. Late postoperative arrhythmias were associated with higher RA pressures measured both early and late after operation and worse late ventricular function. Late arrhythmias may be the first manifestation of RA obstruction, which must be sought. RA thrombus was common in patients with atrial arrhythmias and should be treated early with anticoagulants.     

Peri-operative supraventricular arrhythmias in coronary bypass surgery

One hundred consecutive admissions for coronary bypass surgery were studied to establish the incidence of peri-operative supraventricular arrhythmias, to monitor their evolution, and to identify their possible aetiological factors. No important arrhythmias were detected before the operation. Post-operatively, 24 patients (24%) developed supraventricular arrhythmias. Nineteen of them had atrial fibrillation or flutter (19%), 2 had supraventricular tachycardia (2%), and 3 had inappropriate sinus bradycardia (less than 45 min) (3%). Almost two-thirds of the arrhythmias occurred within the critical early post-operative period (63%). Haemodynamic compromise ushered the onset of arrhythmias in more than one-third of the patients in whom antiarrhythmic measures ensured prompt improvement (37.5%). Three-quarters of those with atrial fibrillation or flutter were back in sinus rhythm at the time of discharge from hospital (74%). The incidence of supraventricular arrhythmia was significantly higher in patients with demonstrable myocardial ischaemia prior to surgery, in patients who underwent adjunctive coronary endarterectomy, or in those in whom topical cardiac cooling was applied (50%, 45%, and 58%, respectively). Supraventricular arrhythmias are frequently encountered during the critical early post-operative period when serious but reversible haemodynamic compromise might be precipitated. Although the nature of the underlying myocardial insult remains obscure, supraventricular arrhythmia may be related more to defective myocardial preservation than to any specific underlying myocardial lesion.     

Arrhythmias after the Fontan procedure

Objective—To study the determinants and outcome of arrhythmias after the Fontan type operation.

Design—Retrospective analysis of data in patients operated on between 1972 and 1986 (follow up 5–19 years (mean 12 years)).

Patients—All 60 patients undergoing a Fontan type procedure at the National Heart Hospital, London, during the study period (mean age (SD) 12·3 (6·8) years).

Results—Postoperative arrhythmias occurred in 34 patients (57%), and 11 (58%) of 19 early postoperative deaths (within seven days) were related to arrhythmias. Early arrhythmias occurred in 19 (32%) patients of whom 11 (58%) died. All patients with early atrial fibrillation and His bundle tachycardia died and only preoperative atrial fibrillation recurred early. There was a higher incidence of early arrhythmias, which were less well tolerated, in double inlet single ventricle patients (9/19) than in those with tricuspid atresia (8/37). There were no other preoperative determinants of early arrhythmias or deaths from early arrhythmia. Late (after seven days) arrhythmias occurred in 15 (37% of hospital survivors). They had higher right atrial (RA) pressures both early and late after operation and had lower ventricular ejection fractions late after operation. Of those with atrial arrhythmias 86% had RA obstruction and 57% had an RA thrombus or pulmonary embolism at presentation; this was also confirmed in two patients in whom late sudden deaths occurred. Atrial fibrillation early after reoperation for RA obstruction was fatal. The actuarial arrhythmia free survival for hospital survivors was 60% at 10 years.

Conclusions—Early postoperative arrhythmias were poorly tolerated, particularly atrial fibrillation and His bundle tachycardia. Previous atrial fibrillation was a relative contraindication to this procedure. Late postoperative arrhythmias were associated with higher RA pressures measured both early and late after operation and worse late ventricular function. Late arrhythmias may be the first manifestation of RA obstruction, which must be sought. RA thrombus was common in patients with atrial arrhythmias and should be treated early with anticoagulants.

     

Electrophysiologic findings after Fontan repair of functional single ventricle

Cardiac arrhythmias are well recognized sequelae of the Fontan operation for complex congenital anomalies. In this study the electrophysiologic effects of the Fontan procedure were evaluated in 30 patients who underwent cardiac catheterization with electrophysiologic study 1.9 +/- 1.3 years (mean +/- SD) after modified Fontan repair for functional single ventricle. Abnormalities of sinus node or ectopic pacemaker automaticity were detected in 50% (15 patients) by determination of a prolonged corrected sinus node or pacemaker recovery time. Total sinoatrial conduction time was prolonged in 50% of the patients with normal sinus rhythm. Sinus node or ectopic atrial pacemaker function was entirely normal in only 43% of patients. The predominant atrial rhythm was normal sinus in 70% and ectopic atrial or junctional in 30%. Abnormalities of atrial effective and functional refractory periods were noted in 43% of patients and were most pronounced at faster paced cycle lengths. Atrial endocardial catheter mapping revealed intraatrial conduction delays between adjacent sites in 76% of the patients tested and in eight of nine patients with inducible intraatrial reentry. Programmed atrial stimulation induced nonsustained supraventricular arrhythmias in 10% of the 30 patients and sustained arrhythmias in 27%. Intraatrial reentry was the most common inducible arrhythmia and was present in seven of the eight patients with sustained and two of the three patients with nonsustained atrial arrhythmias. Atrioventricular conduction abnormalities were noted in 10% (three patients). No patient had inducible ventricular arrhythmias with programmed ventricular stimulation. The electrophysiologic findings after Fontan repair include abnormal sinus node function, prolonged atrial refractoriness, delayed intraatrial conduction and inducible atrial arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term results of the corridor operation for atrial fibrillation.

OBJECTIVE--To investigate the long-term results of the corridor operation in the treatment of symptomatic atrial fibrillation refractory to drug treatment. BACKGROUND--The corridor operation is designed to isolate from the left and right atrium a conduit of atrial tissue connecting the sinus node area with the atrioventricular node region in order to preserve physiological ventricular drive. The excluded atria can fibrillate without affecting the ventricular rhythm. This surgical method offers an alternative treatment when atrial fibrillation becomes refractory to drug treatment. PATIENTS--From 1987 to 1993, 36 patients with drug refractory symptomatic paroxysmal atrial fibrillation underwent surgery. The in hospital rhythm was followed thereafter by continuous rhythm monitoring and with epicardial electrograms. After discharge Holter recording and stress testing were regularly carried out to evaluate the sinus node function and to detect arrhythmias; whereas Doppler echocardiography was used to measure atrial contraction and size. MAIN OUTCOME MEASURES--Maintained absence of atrial fibrillation without drug treatment after operation; preservation of normal chronotropic response in the sinus node. RESULTS--The corridor procedure was successful in 31 (86%) of the 36 patients. After a mean (SD) follow up of 41 (16) months 25 (69%) of the 36 patients were free of arrhythmias without taking drugs (mean (SE) actuarial freedom at four years 72 (9)%)). Paroxysmal atrial fibrillation recurred in three patients; paroxysmal atrial flutter (two patients) and atrial tachycardia (one patient) developed in the corridor in three others. Among the 31 patients in whom the operation was successful sinus node function at rest and during exercise remained undisturbed in 26 and 25 patients respectively (mean (SE) actuarial freedom of sinus node dysfunction at four years (81(7)%)). Pacemakers were needed in five (16%) of the 31 patients for insufficient sinus node rhythm at rest only. Doppler echocardiography showed maintenance of right atrial contribution to right ventricle filling in 26 of the 31 patients after operation in contrast to the left atrium, which never showed such contribution. His bundle ablation was performed and a pacemaker implanted in the five patients in whom the corridor operation was unsuccessful. CONCLUSION--These results substantiate the idea of this surgical procedure. Modification of the technique is, however, needed to achieve a reliable isolation between left atrium and corridor, which would make this experimental surgery widely applicable in the treatment of drug refractory atrial fibrillation.     

肌袖性房性心律失常动态心电图特点及临床意义

目的探讨肌袖性房性心律失常的动态心电图特征及临床意义。方法对11例肌袖性房性心律失常患者的动态心电图及临床资料进行回顾性分析。结果肌袖性房性心律失常均发生在窦性心律的基础上,反复出现短阵房性心动过速、短阵心房扑动、短阵心房颤动等多种房性心律失常。各种房性心律失常常共存或交替出现、连绵不断、长期迁延。发作时间1—20min不等。诱发肌袖性房性心律失常的偶联间期较短,几乎均呈“P—on—T”现象。结论肌袖性房性心律失常是一组具有特征性的房性心律失常,多数患者并无器质性心脏病,药物治疗无效,射频消融术可根治。     

Diagnostik komplexer Arrhythmien

The correct diagnosis of complex arrhythmias requires an exact knowledge of arrhythmia mechanisms and their application in each specific case. In a patient with dilated cardiomyopathy and nonspecific sinus tachycardia, the interpretation of the coronary vein sinus electrogram could quickly raise the possibility of left atrial tachycardia. In a patient with tachycardia, pre-existing left bundle branch block, and syncope, the induction mechanism of the tachycardia in the electrophysiological examination as well as in the detailed analysis of the His bundle electrogram were finally identified as an unusual presentation of AV nodal re-entrant tachycardia. In the patient with broad complex tachycardia and coronary heart disease, successful ablation was only possible with the knowledge that the access to the area of the slow pathway is only possible via the epicardia. Atrial macro re-entrant tachycardia after atrial fibrillation ablation is a growing challenge in clinical rhythmology. An example of this type could be analyzed with the case history of left atrial perimitral atrial flutter after pulmonary vein ablation.     

The Spectrum of Long‐term Electrophysiologic Abnormalities in Patients with Univentricular Hearts

Patients with univentricular hearts experience a wide range of electrophysiolgic abnormalities which tend to develop years after cardiovascular surgical interventions. Intra‐atrial reentrant tachycardia (atrial flutter) in the Fontan population is the most common arrhythmia and, as such, has the largest body of literature addressing its cause and treatment. However, sinus node dysfunction, other atrial arrhythmias, ventricular arrhythmias, and cardiac dysynchrony also occur in this patient population. The purpose of this article is to review the prevalence, mechanisms, and treatment of these electrophysiologic abnormalities within the single ventricle and Fontan patient.     

Time to Cardioversion of Recurrent Atrial Arrhythmias After Catheter Ablation of Atrial Fibrillation and Long‐Term Clinical Outcome

Introduction: It is unclear whether early restoration of sinus rhythm in patients with persistent atrial arrhythmias after catheter ablation of atrial fibrillation (AF) facilitates reverse atrial remodeling and promotes long‐term maintenance of sinus rhythm. The purpose of this study was to determine the relationship between the time to restoration of sinus rhythm after a recurrence of an atrial arrhythmia and long‐term maintenance of sinus rhythm after radiofrequency catheter ablation of AF. Methods and Results: Radiofrequency catheter ablation was performed in 384 consecutive patients (age 60 ± 9 years) for paroxysmal (215 patients) or persistent AF (169 patients). Transthoracic cardioversion was performed in all 93 patients (24%) who presented with a persistent atrial arrhythmia: AF (n = 74) or atrial flutter (n = 19) at a mean of 51 ± 53 days from the recurrence of atrial arrhythmia and 88 ± 72 days from the ablation procedure. At a mean of 16 ± 10 months after the ablation procedure, 25 of 93 patients (27%) who underwent cardioversion were in sinus rhythm without antiarrhythmic therapy. Among the 46 patients who underwent cardioversion at ≤30 days after the recurrence, 23 (50%) were in sinus rhythm without antiarrhythmic therapy. On multivariate analysis of clinical variables, time to cardioversion within 30 days after the onset of atrial arrhythmia was the only independent predictor of maintenance of sinus rhythm in the absence of antiarrhythmic drug therapy after a single ablation procedure (OR 22.5; 95% CI 4.87–103.88, P < 0.001). Conclusion: Freedom from AF/flutter is achieved in approximately 50% of patients who undergo cardioversion within 30 days of a persistent atrial arrhythmia after catheter ablation of AF.     

Holter monitoring in patients with mitral stenosis and sinus rhythm

To determine the type and frequency of supraventricular arrhythmias in patients with mitral stenosis and sinus rhythm we studied 63 such patients, mean (sd) age 48.8 (8.2) years, by 24 hour ambulatory ECG monitoring. Thirty-five patients (55.6%) had supraventricular tachyarrhythmias. Twenty-five (39.7%) had paroxysmal atrial tachycardia, 14 (22.2%) atrial fibrillation, 8 (12.7%) multifocal atrial tachycardia and 5 atrial flutter. Ninety-five per cent (101) of episodes were asymptomatic and 96% non-sustained. Supraventricular premature beats occurred in 59 patients with couplets and triplets in 40 (63.5%) and 28 (44.4%), respectively. Frequent supraventricular premature beats, couplets, triplets and episodes of paroxysmal arrhythmias were commoner in patients greater than 50 years. Ectopic atrial rhythms with varying P wave morphology occurred in 12 patients (19%). Nine patients (14.3%) had suffered systemic embolic episodes. We conclude that supraventricular ectopic and tachyarrhythmias occur frequently in patients with mitral stenosis and sinus rhythm and that most paroxysms are non-sustained and asymptomatic.     

The response of paediatric arrhythmias to intravenous and oral flecainide

Flecainide acetate was administered intravenously and orally to 12 consecutive children, aged 1-15 years, presenting with arrhythmias that were life threatening or resistant to conventional medical treatment. Three children had arrhythmias related to Wolff-Parkinson-White syndrome, four had concealed accessory pathways, two had His bundle tachycardia, and three had ventricular tachycardia. Of seven patients who were given flecainide intravenously, four returned to sinus rhythm and in a fifth successful rate control of His bundle tachycardia was achieved. All 12 patients were given the drug orally: in nine it was successful in preventing recurrence of arrhythmia, in one satisfactory rate control was achieved, and in two it was withdrawn because it produced more frequent attacks of tachycardia. No other adverse effects occurred. The efficacy and low toxicity of treatment in this study suggests that flecainide acetate may have an important role in the management of selected paediatric arrhythmias.     

The response of paediatric arrhythmias to intravenous and oral flecainide.

Flecainide acetate was administered intravenously and orally to 12 consecutive children, aged 1-15 years, presenting with arrhythmias that were life threatening or resistant to conventional medical treatment. Three children had arrhythmias related to Wolff-Parkinson-White syndrome, four had concealed accessory pathways, two had His bundle tachycardia, and three had ventricular tachycardia. Of seven patients who were given flecainide intravenously, four returned to sinus rhythm and in a fifth successful rate control of His bundle tachycardia was achieved. All 12 patients were given the drug orally: in nine it was successful in preventing recurrence of arrhythmia, in one satisfactory rate control was achieved, and in two it was withdrawn because it produced more frequent attacks of tachycardia. No other adverse effects occurred. The efficacy and low toxicity of treatment in this study suggests that flecainide acetate may have an important role in the management of selected paediatric arrhythmias.     

Spectrum of regular tachycardias with wide QRS complexes in patients with accessory atrioventricular pathways

Reciprocating tachycardia and atrial flutter or fibrillation are the rhythm disorders most frequently documented in patients with accessory atrioventricular (A-V) pathways. Reciprocating tachycardia typically results in a regular tachycardia (140 to 250/min) with a normal QRS pattern, although on occasion bundle branch block aberration occurs. Atrial flutter or fibrillation may result in an irregular ventricular response, with the QRS configuration being normal or exhibiting bundle branch block or various degrees of ventricular preexcitation, or both. Although much less common than either reciprocating tachycardia or atrial flutter/fibrillation, regular tachycardias with a wide QRS complex suggestive of ventricular preexcitation are observed in patients with accessory pathways. Excluding functional or preexisting bundle branch block, several arrhythmias may cause these electrocardiographic findings which may mimic those of ventricular tachycardia.In the present study a variety of arrhythmias that resulted in tachycardias with a wide QRS complex were examined in 163 patients with accessory pathways who underwent clinical electrophysiologic study for evaluation of recurrent tachyarrhythmias. Twenty-six patients (15 percent) manifested a regular tachycardia with a wide QRS complex suggesting ventricular preexcitation. Atrial flutter with 1:1 anterograde conduction over an accessory pathway (15 of 26 patients, 58 percent) was the most frequent arrhythmia and was usually associated with a heart rate of 240/min or greater (12 of 15 patients). Reciprocating tachycardia with conduction in the anterograde direction over an accessory pathway (antidromic reciprocating tachycardia) occurred in 7 of 26 patients (27 percent), and resulted in a slower ventricular rate than atrial flutter (217 ± 22 versus 262 ± 42, P < 0.01). Other arrhythmias included reciprocating tachycardia with reentry utilizing a fasciculoventricular or nodoventricular connection (two patients, 8 percent), reciprocating tachycardia with reentry in the atrium or A-V node and anterograde accessory pathway conduction (one patient, 4 percent) and ventricular tachycardia (one patient, 4 percent).In this study the clinical electrophysiologic diagnostic features of several arrhythmias which cause tachycardias with a wide QRS compex suggesting ventricular preexcitation are outlined. It is apparent that definitive arrhythmia diagnosis during these tachycardias is often complex and usually requires careful study using intracardiac electrode catheter techniques.