a Departments of Cardiology and Cardiothoracic Surgery, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands
b Department of Cardiothoracic Surgery, Thoraxcenter, Erasmus Medical Centre, Rotterdam,The Netherlands
c Department of Child and Adolescent Psychiatry, Sophia Children's Hospital, Rotterdam,The Netherlands
Received March 5, 2002; accepted May 23, 2002 * Correspondence: J. W. Roos-Hesselink, Thoraxcenter Ba 308, Erasmus Medical Centre Rotterdam, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
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Abstract |
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Methods and Results One hundred and thirty-five consecutive ASD-patients, operated on in childhood, were studied longitudinally with ECG, echocardiography, exercise testing and Holter-recording 15 (1022) and 26 (2133) years after surgery. During follow-up no cardiovascular mortality, stroke, heart failure and no pulmonary hypertension occurred. Symptomatic supraventricular tachyarrhythmias were present in 6% after 15 years, and an additional 2% occurred in the last decade; 5% needed pacemaker implantation. No relation was found between arrhythmias and type of ASD, baseline data, right ventricular dimensions, or age at operation. Left and right ventricular function and dimension remained unchanged. Slightly more patients had right atrial dilatation at last follow-up. Exercise capacity was comparable with the normal Dutch population.
Conclusions The long-term outcome after ASD closure at young age shows excellent survival and low morbidity. The incidence of supraventricular arrhythmias is lower than in natural history studies of ASD patients and also lower than after surgical correction at adult age.
Key Words: Secundum atrial septal defect heart surgery long-term follow-up supraventricular arrhythmias
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Introduction |
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The aim of this study is to provide data on mortality and morbidity, which is critically important with regard to employment and acceptance on insurance schemes in long-term survivors of repair of atrial septal defects, and can also be used for comparison with the recently developed device closure techniques.
We present a longitudinal follow-up of 2133 years (mean 27 years) after surgical closure of an atrial septal defect in 135 patients who underwent this operation at the Thoraxcentre between 1968 and 1980 and were <15 years of age at the time of surgery. Stroke, heart failure, incidence of arrhythmias, changes in ECG, exercise capacity and echocardiographic parameters were studied. Inaddition, the predictive value of the asymptomatic arrhythmias seen on the Holter recordings 10 years ago is determined.14
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Methods |
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Electrocardiography
Standard 12-lead surface electrocardiograms were analysed for the height of the P wave (measured in lead II), duration of the P wave and the PR interval (measured from the initial deflection of the P wave to the initial deflection of the QRS complex). A first-degree atrioventricular block was defined by a PR interval >200 ms. In addition, the widest QRS duration was determined (from the initial deflection of the QRS complex to where the terminal deflection crosses the baseline, taken in any chest lead with the widest complex and where the deflections were acute enough to permit accurate assessment). A QRS duration >120 ms was defined to be a complete bundle branch block. A single observer made all ECG measurements (J.R.-H.).
Holter monitoring
A three-channel recorder was used. Sinus node dysfunction was assessed during 24 h Holter monitoring using the modified Kugler criteria: nodal escape rhythm, sinus arrest >3 s or severe sinus bradycardia (<40 beats.min1at night or <50 beats.min1during daytime).13
Echocardiography
Two-dimensional echocardiography and echo-Doppler studies were performed using a Hewlett-Packard Sonos 5500 echocardiograph. All echocardiographic studies were performed on the same machine. Left atrial dimension and left ventricular end-diastolic and end-systolic dimensions were assessed using M-mode echocardiography in the parasternal view. A left atrium dimension>45 mm and a left ventricular end-diastolic dimension of >58 mm were considered enlarged. A fractional shortening less then 0.30 was defined as decreased. Parasternal, apical four-chamber and subcostal views were used to assess right atrium and right ventricular dimensions. This was done by visual estimation by two experienced cardiologists (F.M. and S.S.). Multiple echocardiographic views were examined using colour flow to identifyresidual shunts. Doppler-echocardiography was used for the assessment of blood flow velocities. Right ventricular systolic pressure was estimated from tricuspid regurgitation jet velocity; diastolic pulmonary pressure from the pulmonary regurgitation flow velocity. Pulmonary hypertension wasdefined as a tricuspid regurgitation flow velocity >3.0 or a pulmonary regurgitation flow velocity >2.5 m.s1.
Bicycle ergometry
Maximal exercise capacity was assessed by bicycle ergometry with stepwise increments of workload of 20 Watts per minute. Exercise capacity was compared to that in normal individuals correctedfor age, sex, and body height. Exercise capacity <85% of the predicted value was considered to be decreased.
Arrhythmias were defined to be symptomaticif antiarrhythmic medication was prescribed,cardioversion was necessary, catheter ablation or surgical arrhythmia treatment had been applied, or pacemaker implantation had been necessary. Major events were defined as cardiac surgery, stroke, symptomatic arrhythmia, or an episode of heart failure.
Data analysis
Data are presented as mean values and standard deviation, unless indicated otherwise. The Chi-square and Fisher's exact test were used for the comparison of discrete variables. The Student t-test was used to compare continuous variables. The level of significance was chosen at P<0.05.
Tests were performed for the patients as a total, as well as separately for the secundum type ASD and the sinus venosus type group. Results of the total group will be presented, unless significant differences were observed between the two subgroups.
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Results |
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Major cardiac events
Before 1990 one additional cardiac operation was performed for closure of a patent arterial duct. No cardiac operations were necessary between 1990 and 2001. No stroke and no episodes of heart failure occurred during follow-up. No patient was using diuretics. In 1990 symptomatic supraventriculararrhythmias were present in seven patients (6%): three were treated medically for periods of atrial flutter or fibrillation, and four others needed pacemaker implantation. Of these seven patients, three were readmitted between 1990 and 2001: onepatient suffered from pacemaker endocarditis,he was treated with antibiotics for 6 weeks andthe pacing system was replaced, while two other patients needed pacemaker battery replacement. Between 1990 and 2001, three additional patients had new symptomatic arrhythmias: one needed pacemaker implantation for sinus node disease, one patient had recurrent atrial flutter treated with several electrical cardioversions and radiofrequency catheter ablation, and one patientreceived medical therapy for supraventriculararrhythmias. Analyses were performed, investigating the role of localization of the ASD (secundum type or sinus venosus type), baseline data (such as pre-operative shunt size, age at operation, yearof operation, and surgical techniques), right ventricular and atrial dimensions at follow-up, age at follow-up and duration of follow-up in relationto the presence or absence of symptomaticarrhythmias. No relation was found.
Medical history and physical examination
When questioned about their current general health, 88.3% considered their health as very good or good, and 11.7% as moderate. None judged it as poor. This is not different from the health assessment of the normal Dutch population.16 Patient's own appreciation of their physical condition was better in 13%, the same in 51%, slightly worse in 33% and much worse in 3% compared with that of 11 years previously.14 On the question whether the patients suffered from palpitations, 20% answered yes in 1990 and 28% in 2001. Physical examination revealed that the mean height of the patientsremained unchanged (172.4mm in 1990 and 172.5mm in 2000), whereas the mean weight rose from 64.1kg in 1990 to 73.7kg in 2000 (P<0.0001). The mean pulse rate lowered from 72 to 67 beats.min1(P=0.0004). Signs of heart failure were not found.
Electrocardiography
Twelve-lead electrocardiograms and 24-h ambulatory electrocardiograms data are presentedin Table 2. Sinus rhythm was seen in 1990 in 90% of the patients and 89% in 2001. The PR-interval did not change during this 10-year period. P-waveduration and P-wave height did not change significantly over 10 years. The QRS duration increased, but no new bundle branch block occurred.
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Echocardiography
Echocardiographic findings are summarized inTable 3 and 4. Residual shunts were not found. Dimension of right ventricle, left atrium and left ventricle remained unchanged over time. Thepercentage of patients with right atrium dilatation increased from 5.8% in 1990 to 18.7% in 2001 (P=0.5). Mitral valve regurgitation did not progress in 10 years and none of the patients developed substantial pulmonary regurgitation. Haemodynamically insignificant pulmonary and tricuspid regurgitation did not progress, but one patientdeveloped severe aortic regurgitation. No pulmonary hypertension was found and estimated pulmonary artery pressure was stable over time. Left and right ventricular function remained unchanged over the last 10 years, and none of the patients experienced a less than 20% left ventricular shortening fraction at last follow-up. Although 20% of the patients had left ventricular shortening fraction of between 20 and 30%, most of these patients had post-operative abnormal septal motions, but were judged otherwise to have normal systolic function, only 4.5% of the total group was judged as having diminished systolic left ventricular function. Only one patient showed paradoxical septal motion.
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Discussion |
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The development of atrial arrhythmias isdescribed after ASD closure, and has been studied thoroughly in adults.8,17,18 Studies of long term follow-up in adults demonstrate that the incidence of new atrial arrhythmias is unchanged following surgical closure of ASD compared to those treated conservatively. Some studies suggest that olderage at operation is a risk factor for persistentatrial arrhythmias and development of new atrial arrhythmias after surgery,1719 while the incidence of atrial arrhythmias appears lower in patientsoperated at younger age. Nevertheless, Meijboom et al. report that up to 45% of the patients had some form of asymptomatic atrial arrhythmias on Holter recording, 15 years after surgery.8,14 In this same cohort of patients we observed a low incidence (2%) of symptomatic arrhythmias in the subsequent decade and in 36% asymptomatic atrial arrhythmias. No patient had chronic atrial fibrillation, one patient developed persistent atrial flutter, one needed pacemaker implantation, and one patient received antiarrhythmic medication forsupraventricular tachycardias. Thus, the predictive value of the asymptomatic arrhythmias seen on Holter recording seems limited. The prevalenceof atrial fibrillation in the general population is studied mainly in older age groups and is estimated to be 3/1000 in those aged 4549 years.20 The reported incidence of atrial fibrillation and flutter in natural history studies of ASD patients is 1540% in 3035-year-olds and comparable with the incidence of arrhythmias after surgical ASD closure at adult age. This is substantially higher then the 3% found in our study,1,17,18,20 suggesting that early closure is beneficial indeed. The aetiology of late atrial arrhythmias following surgical closure of ASD is not well explained. Long-standing volume overload, varying degrees of pulmonary hypertension, ventricular dysfunction, congenital defects in the atrial conduction tissue, and surgical scars have all been implicated.22,23 Our data imply that it isunlikely that the congenital defect in the conduction tissue is an important factor in the aetiology of the arrhythmias, since few symptomatic arrhythmias occurred. It is possible that the atria of young patients have greater remodelling potential and that this patient population may therefore be at lower risk for the development of late atrialarrhythmias.6 Transcatheter device closure may have an extra advantage over surgical closure on the incidence of arrhythmias, but improvement of right heart morphology after device closure and the effect of avoidance of an atriotomy scar remain to be determined.24 Electrocardiographic parameters such as P wave height and PR interval, which may predict the occurrence of atrial arrhythmias,remained stable for 10 years. This, together with the low incidence of new symptomatic arrhythmias in the last 10 years, leads to the prediction that only few additional arrhythmias will develop in these patients. Continuing follow-up is warranted to verify this assumption.
The clinical condition of the patients appeared excellent at follow-up: the exercise capacity was comparable with normal individuals corrected for age, sex and body height. The incidence of right ventricular dilatation and valve regurgitation on echocardiographic images was low, and not different from 10 years ago. The percentage of patients with a dilated right atrium increased from 5.8 in 1990 to 18.7% in 2001. This was not a significant increase (P=0.5), but also others reported aremaining dilatation of the right atrium after ASD closure compared to controls.24
Whether transcatheter device closure will have the same excellent results remains to be determined, especially while up to 50% of the patients have residual shunts after device closure after1 year of follow-up.6
In our study we found no differences in outcome between the patients with sinus venosus type ASD and secundum type ASD with regard to the incidence of arrhythmias, exercise capacity and haemodynamic status.
Study limitations
In this study the follow-up is incomplete. After15 years 104 (77%) and after 26 years, 94 (70%) from the originally 135 operated patients participatedin the study. Since 1990, one patient has died,five were lost and four were unwilling to attend hospital. Nevertheless, the latter four patients did return the questionnaire, and reported to be in good clinical health.
Furthermore, we found no difference in characteristics between the patients who did and who did not participate in the follow-up study, so we expect that the incomplete follow-up will have no impact on the outcome of the study.
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Conclusion |
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These excellent long-term results are critically important for the employability and insurability, and ASD patients should encounter no obstaclesin finding jobs and have life insurance policies consistent with standard rates.
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Acknowledgments |
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References |
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