High frequency of arrhythmias after Fontan operation indicates earlier anticoagulant therapy

BACKGROUND: As patients began to survive for longer periods following modified Fontan operations (conventional atrio-pulmonary connection), the late morbidity after this procedure became increasingly apparent. The purpose of the present study was to evaluate late sequelae of modified Fontan operations in long-term survivors (n=14) at our institute. METHODS AND RESULTS: The cohort consisted of patients who underwent a modified Fontan operation between 1981 and 1990. Thus, all patients were examined at least 10 years postoperatively in this study. Early mortality, within 30 days of the operation, was 17.6% (three of 17 patients died from low output syndrome). Excluding these early deaths, the cumulative survival rate at 5 and 10 years was 100 and 79%, respectively. Arrhythmias including atrial fibrillation or flutter were the main late causes of morbidity. The arrhythmia-free rate at 5 and 10 years was 77 and 50%, respectively. Although the quality of life was considered good because all patients (n=11) who survived for 10 years or more were in class I or II according to the New York Heart Association classification, most of them in fact suffered from potentially life-threatening arrhythmias. CONCLUSIONS: Meticulous attention to and utilization of established treatment strategies for arrhythmias including anti-arrhythmics, anticoagulants, catheter ablation or re-operation converting the circulation to the total cavopulmonary connection must be considered in long-term survivors following the modified Fontan operation. The fact that no one knows when the thrombogenic arrhythmias occur suggests anticoagulants should be initiated in the early postoperative period.     

Impact of arrhythmia circuit cryoablation during Fontan conversion for refractory atrial tachycardia

Refractory atrial arrhythmias in late postoperative Fontan patients are usually associated with residual hemodynamic abnormalities and result in significant morbidity and mortality. Surgical revision of the Fontan anastomosis may improve hemodynamics without eliminating tachycardia. This study sought to assess the impact of surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion on the clinical recurrence of tachycardia. Sixteen consecutive atriopulmonary Fontan patients with refractory atrial arrhythmias underwent surgical conversion to lateral tunnel total cavopulmonary anastomosis (15) or Fontan revision (1 patient). The initial 4 patients underwent Fontan conversions alone, without specific arrhythmia surgery. The subsequent 12 patients underwent electrophysiologically guided cryoablation of the tachycardia circuits at the time of surgical conversion. The mean age at Fontan revision was 15.6 +/- 3.8 years. Cryoablation was directed to 3 identified major tachycardia circuits: the inferomedial right atrium, the superior rim of the prior atrial septal defect patch, and along the lateral right atrial wall. Transmural antitachycardia pacemakers were implanted in 11 of the 16 patients. There was no surgical mortality in either group, and all patients improved in functional classification. All patients not undergoing cryoablation experienced recurrent symptomatic tachycardia requiring antiarrhythmic therapy (median follow-up, 54 months) versus 2 of 12 patients receiving cryoablation (median follow-up, 25 months; p <0.02). Thus, surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion is highly effective in the management of refractory atrial arrhythmias, and is superior to Fontan conversion alone.     

The adult with a Fontan operation

Since 1971, the Fontan operation has been performed for the repair of single-ventricle physiology. This ingenious operation commits a single ventricle to the systemic circulation and takes advantage of cardiovascular and respiratory physiology to propel deoxygenated blood to the lungs, thus minimizing right-to-left shunting and cyanosis. Initially performed as a right atrial to pulmonary artery anastomosis, the Fontan operation has gone through evolutionary steps that have resulted in progressive improvements in mortality, morbidity, and outcomes. Inclusion of the right atrium in the slow-flowing Fontan circuit results in progressive dilation and incessant arrhythmias. This spurred forth efforts to create modifications that partially or completely exclude the atrium from the Fontan circuit. The transcatheter completion of the Fontan operation has been performed in a small number of patients and we expect minimally invasive, transcatheter, and hybrid interventions to play an important role in the future management of these patients.     

Percutaneous management of cyanosis in Fontan patients using Amplatzer occluders

Objectives : To determine causes of cyanosis and to evaluate percutaneous management of cyanosis in a group of consecutive Fontan patients. Background : A variety of communications allow a right‐to‐left shunt in Fontan circulation causing cyanosis and these communications are amenable to percutaneous closure. Methods : Between November 1997 and November 2007, 45 consecutive patients ranging in age from 2.5 to 26 years (median 8 years) with Fontan circulation and cyanosis underwent cardiac catheterization and percutaneous closure of superfluous communications using different types of Amplatzer occluders. Results : Altogether, 51 communications were detected and 50 of them were closed. In 5 patients (11.1%), multiple communications were present and were closed. Fenestration was detected in 37 of 41 patients (90.2%) after total cavopulmonary connection and all were closed by Amplatzer septal occluders. Five venous collaterals were revealed in 3 of 41 patients (7.3%) with total cavopulmonary anastomosis and were closed by Amplatzer vascular plugs. In 3 patients, lateral tunnel leaks were detected and were closed by Amplatzer PFO occluders. In 4 patients after Kawashima operation, 3 major pulmonary arterio‐venous malformations and single venous collateral contributed to the cyanosis and all were closed using Amplatzer vascular plugs. Conclusions : Different communications cause cyanosis in Fontan patients. Progressive decline of percutaneous oxygen saturation is suggestive of development of venous collaterals or pulmonary arteriovenous malformations. Superfluous communications are amenable to percutaneous closure using various types of Amplatzer occluders. A novel use of an Amplatzer PFO occluder for the percutaneous closure of a lateral tunnel leak is described. © 2008 Wiley‐Liss, Inc.     

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.     

Single-stage Fontan procedure: early and late outcome in 124 patients

INTRODUCTION AND OBJECTIVES: The Fontan procedure was designed to palliate complex congenital heart disease with univentricular physiology. A retrospective study was made to document the determinants of early (/= 31 days) mortality with the modified Fontan procedure performed in one-stage over a 22-year period. MATERIAL AND METHODS: Between 1978 and 2000, 102 atriopulmonary, 16 cavopulmonary, and 6 Kawashima type anastomoses were performed to palliate complex congenital heart defects in 124 patients with a mean age of 7.3 4.7 years. Forty-five patient and procedure-related variables were analyzed in relation to mortality. All events were verified. RESULTS: There were 29 early (23%) and 20 late (16%) deaths. Estimated survival at 30 days, 2 years, 5 years, and 20 years was 78, 75, 66, and 50%, respectively. Subaortic stenosis, protein-losing enteropathy, and arrythmia were observed in 8, 5 and 33 patients, respectively, after surgery. Univariate and multivariable analysis indicated that left ventricular end-diastolic pressure (>/= 13 mmHg), mean pulmonary pressure (>/= 19 mmHg), mitral stenosis/atresia, atrioventricular valve regurgitation, visceral heterotaxia, absence of fenestration, risk factors criteria, duration of extracorporeal circulation, and operative technique were associated with early mortality. Reoperation, arrhythmia, and pacemaker implantation were predictors of late death. Forty percent remained free from surgical or catheter reintervention after Fontan operation at 20 years. CONCLUSIONS: The outcome of Fontan procedure is profoundly affected by patient-related variables (ventricular function and pulmonary circulation). Postoperative arrhythmia and reoperation shortened the lifespan of the Fontan circulation model in patients with atriopulmonary connections. Total cavopulmonary anastomosis improves the physiology of univentricular circulation. In the light of our findings, the modified Fontan procedure (one or two stages) should be performed early in life to better preserve ventricular and pulmonary vascular function.     

P wave signal averaged electrocardiography in patients undergoing the Fontan operation

OBJECTIVES: Supraventricular arrhythmias are one of the most common and fatal sequelae of the Fontan operation. P wave triggered signal averaged electrocardiography was performed in patients undergoing the Fontan operation to evaluate the presence of atrial degeneration, and to clarify which factors affected the development of atrial arrhythmias. METHODS: P wave triggered signal averaged electrocardiography was recorded in 14 patients after the Fontan-type operation (conventional atriopulmonary connection in 5 and total cavopulmonary connection in 9) and 15 healthy controls. The duration and area of the filtered P wave, and the signal magnitudes (M20, M30) at 20 Hz and 30 Hz obtained from the frequency domain analysis of the P wave (M20, M30) were evaluated and compared with the hemodynamic data. RESULTS: The duration and area of the filtered P wave, M20 and M30 in patients after atriopulmonary connection were significantly greater than in those after total cavopulmonary connection and the control subjects (p < 0.05). M20 was significantly greater in patients after total cavopulmonary connection than in the control subjects. Right atrial volume in patients after atriopulmonary connection was significantly (p < 0.001) larger than in patients after total cavopulmonary connection (p < 0.05). There were no significant differences in other indices including atrial pressure between the two groups. CONCLUSIONS: Our results suggest that the substrate for atrial arrhythmias such as atrial myocardial degeneration and fibrosis is frequently present in patients after the Fontan operation, especially after atriopulmonary connection. Thus, the enlarged right atrium may be involved in the presence of a substrate for atrial arrhythmias. The developmental risk for late atrial arrhythmias seems to be present even in patients after total cavopulmonary connection.     

Outcomes of late atrial tachyarrhythmias in adults after the Fontan operation

OBJECTIVES: The purpose of this study was to compare the clinical and echocardiographic features of adults who developed atrial tachyarrhythmias (ATs) late after a Fontan procedure with those who have remained free of arrhythmias. BACKGROUND: Atrial tachyarrhythmias are a frequent complication of the Fontan operation. However, the outcomes in adult patients with AT who have had the Fontan operation have not been well defined. METHODS: We reviewed the outcomes of 94 consecutive patients who underwent the Fontan operation between 1977 and 1994 and were followed as adults at the University of Toronto Congenital Cardiac Centre for Adults. Sixty patients had an atriopulmonary connection, 21 patients had an atrioventricular connection, and 13 patients received a lateral tunnel connection. RESULTS: Thirty-nine patients (41%) had sustained AT (atrial fibrillation, atrial flutter or supraventricular tachycardia) after their Fontan procedure. Compared with patients who did not develop AT, those who did were more likely to develop heart failure (46% vs. 13%, p = 0.003) and right atrial thrombus (31% vs. 4%, p = 0.006), exhibit left atrial enlargement (mean [+/-SD] diameter: 44 +/- 10 vs. 37 +/- 9 mm, p = 0.002), exhibit right atrial enlargement (mean [+/-SD] volume: 139 +/- 149 vs. 76 +/- 54 ml, p = 0.040) and have moderate-to-severe systemic valve regurgitation (31% vs. 7%, p = 0.010). The mean survival time was not significantly different between the arrhythmia group and the arrhythmia-free group (21.2 +/- 1.3 and 18.0 +/- 0.7 years, respectively; p = 0.900). CONCLUSIONS: Systemic atrioventricular valvular regurgitation and biatrial enlargement are commonly observed in patients who develop AT after the Fontan procedure. These patients are more likely to develop right atrial thrombus and heart failure.     

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.     

The fenestrated Fontan procedure.

In 90 patients with characteristics placing them at increased risk for a Fontan operation, a fenestration was created in the atrial baffle at the time of the Fontan repair. The rational was to allow a right to left shunt which would maintain cardiac output and limit right atrial pressure in the presence of conditions which limit pulmonary blood flow. Early mortality was 4/90 (4%), with an additional two patients having the Fontan repair taken down to a bidirectional cavopulmonary anastomosis. Postoperative right atrial pressures were low (average 13 mm Hg), as was the incidence of prolonged pleural effusions (13%). At short-term (average 13 months) follow-up, 77% of patients have had closure of the fenestration, and 92% are in New York Heart Association Class I. We conclude that baffle fenestration with subsequent transcatheter closure results in decreased mortality and morbidity among high risk patients undergoing a Fontan repair, and that the high functional level at short-term follow-up justifies continued aggressive management of such patients.     

Hybrid trans‐apical atrioventricular valve‐in‐valve implantation in Fontan circulation

Trans‐apical approach has been proved successful in failing surgical bio‐prosthesis in both mitral and aortic position in adult patients. Recently, valve‐in‐valve treatments have been applied even in patients with complex congenital heart disease. Here, we report the case of a 32 years old lady with left atrial isomerism, complete AV septal defect, interrupted inferior vena cava with azygos continuation who underwent Kawashima procedure with atrial Fontan. Severe systemic atrioventricular valve regurgitation necessitated a 33 mm Perimount valve implantation and conversion to lateral tunnel Fontan. After only 4 years there was severe valve stenosis and the patient underwent successful trans‐apical transcatheter implantation of a 29 mm Sapien valve.     

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)     

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.

     

Evolving electroanatomic substrate and intra-atrial reentrant tachycardia late after Fontan surgery

Atrial Remodeling After the Fontan Operation. Introduction: The prevalence of intra‐atrial reentrant tachycardia (IART) increases with age in Fontan patients. This study aimed to characterize the atrial electroanatomic substrate for IART late after Fontan surgery. Methods and Results: Detailed electroanatomic mapping of the right atrium (RA) was performed in 11 consecutive patients (33 ± 9 years) with older style Fontan circulation (atriopulmonary and atrioventricular connection) who underwent their first radiofrequency catheter ablation (RFCA) for IART. A comparative group of 30 non‐Fontan congenital heart disease (CHD) patients were also studied. Fontan patients had larger RA (P = 0.004), larger low‐voltage area ≤0.5 mV (P = 0.01), and more fractionated potentials (P < 0.001) than non‐Fontan CHD patients. RA enlargement correlated significantly with both low‐voltage zones (Spearman ρ= 0.68, P < 0.001) and fractionated potentials (Spearman ρ= 0.48, P = 0.001). Among Fontan patients, both age and time since Fontan surgery were significantly correlated to the amount of low‐voltage areas (Spearman ρ= 0.87, P < 0.001; Spearman ρ= 0.63, P = 0.04, respectively). Successful RFCA was accomplished in 30 (73%) patients and was less likely in Fontan patients (54% vs 83%, P = 0.04). Larger RA was significantly associated with a lower success rate (P = 0.04). During a follow‐up duration of 2.3 ± 1.6 years, IART recurred in 47% of patients. Larger RA size and larger low‐voltage areas predicted IART recurrence after RFCA. Conclusion: Fontan patients demonstrate progressive adverse atrial electrical remodeling with increasing age and time since surgery. Newer strategies beyond surgical incisions, such as pharmacotherapies that retard the progression of atrial fibrosis, may be required to reduce the long‐term risk of atrial arrhythmias.     

Abnormal cardiac signs after Fontan type of operation: indicators of residua and sequelae.

Among 74 survivors of the Fontan type of operation abnormal cardiac signs were detected in 46 (62%) at postoperative examination. The findings were analysed in relation to the state of the cardiovascular system of these patients. Cyanosis was present in 10 (13.5%) patients. The causes of cyanosis included residual interatrial shunt (six patients), acquired pulmonary arteriovenous fistulas (three patients) and acquired systemic-to-pulmonary vein communication (one patient). Signs of chronic fluid retention were detected in six (8%) patients. In four of them the fluid retention was related to conduit obstruction and in the remaining two it was secondary to severe subaortic stenosis in one and atrioventricular valvar regurgitation in the other. Organic heart murmurs were heard in 29 (39%) patients. The aetiologies of these murmurs were multiple. They included aortic valve regurgitation (eight patients), subaortic stenosis (seven patients), atrioventricular valvar regurgitation (five patients), pulmonary valve regurgitation (five patients), residual Blalock-Taussig shunt (two patients), residual ventricular septal defect (two patients), residual communication in the main pulmonary artery which had been ligated but not divided (one patient), and left ventricular to right atrial shunting (one patient). Cardiac rhythm disturbances of varying aetiology were noted in 23 (31.1%) patients. Sixteen (21%) had supraventricular arrhythmias and seven (9.5%) had conduction abnormalities. The present review suggests that among survivors of the Fontan type of operation abnormal cardiac signs are indicators of residua or sequelae or both of the native cardiovascular anomalies or surgical procedures.     

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.     

Abnormal cardiac signs after Fontan type of operation: indicators of residua and sequelae

Among 74 survivors of the Fontan type of operation abnormal cardiac signs were detected in 46 (62%) at postoperative examination. The findings were analysed in relation to the state of the cardiovascular system of these patients. Cyanosis was present in 10 (13.5%) patients. The causes of cyanosis included residual interatrial shunt (six patients), acquired pulmonary arteriovenous fistulas (three patients) and acquired systemic-to-pulmonary vein communication (one patient). Signs of chronic fluid retention were detected in six (8%) patients. In four of them the fluid retention was related to conduit obstruction and in the remaining two it was secondary to severe subaortic stenosis in one and atrioventricular valvar regurgitation in the other. Organic heart murmurs were heard in 29 (39%) patients. The aetiologies of these murmurs were multiple. They included aortic valve regurgitation (eight patients), subaortic stenosis (seven patients), atrioventricular valvar regurgitation (five patients), pulmonary valve regurgitation (five patients), residual Blalock-Taussig shunt (two patients), residual ventricular septal defect (two patients), residual communication in the main pulmonary artery which had been ligated but not divided (one patient), and left ventricular to right atrial shunting (one patient). Cardiac rhythm disturbances of varying aetiology were noted in 23 (31.1%) patients. Sixteen (21%) had supraventricular arrhythmias and seven (9.5%) had conduction abnormalities. The present review suggests that among survivors of the Fontan type of operation abnormal cardiac signs are indicators of residua or sequelae or both of the native cardiovascular anomalies or surgical procedures.     

HCN离子通道对Fontan循环下发生房性心动过速的作用

目的:探讨HCN离子通道对Fontan循环下发生房性心动过速的作用。方法:通过外科手术建立Fontan比格犬模型,术前及术后1周行心脏超声测量右心房大小,穿刺测量右心房和肺动脉压力,行右心房组织病理学检查观察右心房组织的纤维化程度。使用TaqMan实时定量PCR检测右心房肌细胞中HCN2和HCN4 mRNA表达水平,Western blot检测右心房肌细胞中HCN2和HCN4蛋白表达水平,全细胞膜片钳技术检测右心房肌细胞If通道电流。结果:共18只犬进行手术,其中存活5只,Fontan术后存活1周犬右心房内径较术前增加[(17.08±1.73)mm对(13.90±1.25)mm,P0.01],右心房压力增高[(17.80±2.39)mmHg对(8.40±1.14)mmHg,P0.01],肺动脉压力无明显变化[(12.60±2.41)mmHg对(13.00±2.74)mmHg,P0.05]。模型犬右心房组织纤维化程度较对照组增加(P0.05);模型犬术后右心房心肌细胞HCN2和HCN4 mRNA表达水平均较对照组升高(P均0.05),HCN2和HCN4的蛋白表达水平均较对照组升高(P均0.05);HCN通道电流较正常对照组增大,钳制电压为-140 mV时,模型组和对照组电流密度分别为(-1.98±0.14)pA/pF和(-1.09±0.09)pA/pF,P0.01。结论:Fontan循环下心房肌细胞HCN离子通道表达上调,HCN电流增大,可能参与房性心动过速的发生。     

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.     

Long-term anticoagulation therapy and thromboembolic complications after the Fontan procedure

BACKGROUND: The necessity for chronic anticoagulation of Fontan patients remains controversial. We determined the prevalence of thromboembolic complications after the Fontan procedure in relation to different long-term anticoagulation strategies. METHODS: The clinical outcomes, postoperative anticoagulation strategies and occurrence of thromboembolic complications in 102 ethnic Chinese patients who had undergone Fontan procedure between 1980 and 2002 were reviewed. RESULTS: The early and late surgical mortalities, all unrelated to thromboembolism, were 10.8% (11/102) and 5.8% (6/104), respectively. Of the 85 survivors, 46 (54%) were maintained on long-term warfarin therapy, 8 (9%) on aspirin prophylaxis while 31 (37%) were not on chronic anticoagulation. Four (4.5%) patients, two with and two without warfarin prophylaxis, developed thromboembolic complications at 0.14 to 7.7 years after the Fontan procedure (0.74%/patient-year). Three had a grossly dilated right atrium after atriopulmonary connection, two of whom had atrial fenestrations. The other had atrial tachycardia. Freedom from development of thromboembolic complications (mean+/-S.E.) at 1, 5 and 10 years after surgery was 97+/-19%, 96+/-2.5% and 92+/-4.2%, respectively. When compared with those on long-term warfarin therapy, patients without chronic anticoagulation were followed-up longer (p=0.001), more likely to have undergone atriopulmonary connection (p<0.001), less likely to have fenestrations (p=0.02) and cardiac arrhythmias (p=0.02) but not predisposed to increased risk of thromboembolism (p=1.00). CONCLUSION: The study supports the contention that chronic anticoagulation may not be required for majority of ethnic Chinese Fontan patients. Nonetheless, it may perhaps be considered in those with grossly dilated right atrium, cardiac arrhythmias and residual right-to-left shunts.