Sinus Venosus Atrial Septal Defect: Early and Late Results Following Closure in 109 Patients

Sinus Venosus Atrial Septal Defect: Early and Late Results Following Closure in 109 Patients El Ross Kyger, 111, M.D., 0. Howard Frazier, M.D., Denton A. Cooley, M.D., Paul C. Gillette, M.D., George J. Reul, Jr., M.D., Frank M. Sandiford, M.D., and Don C. Wukasch, M.D. ABSTRACT The clinical course of 109 patients who underwent closure of a sinus venosus atrial septal defect is reviewed, with emphasis on the incidence, type, and severity of arrhythmias before and after operation. There were no operative deaths and only 1 late death. No instances of obstruction of the superior vena cava were detected clinically. One patient had a probable hemorrhagic pulmonary infarction that cleared; another may have a persistent left-to-right shunt. Excellent results were achieved in 72% of the patients, good results in 2070, fair results in 5%, and poor results in 3%. The type of arrhythmia, both before and after operation, varied with the age of the patient: younger patients had bradyarrhythmias, and older patients had tachyarrhythmias. Ten patients experienced persistent new arrhythmias postoperatively, but none were disabled, required a pacemaker, or died. The arrhythmias in all severely symptomatic patients were supraventricular tachycardias that had occurred before operation. Although functional classification after operation was clearly related to age at the time of the procedure (with younger patients having the best functional results), 19 of 21 patients over age 40 were noticeably improved after surgical closure of the sinus venosus atrial septal Materials and Methods defect. Atrial septal defect (ASD), a relatively common congenital cardiac defect, was the first to be repaired using the pump oxygenator [3]. During the past twenty years, refinements in surgical technique for repair of these abnormalities have aided in lowering the operative mortality. The risk of death is no longer a major deterrent to surgical repair, and attention is now properly From the Division of Surgery of the Texas Heart nstitute, St Luke s Episcopal and Texas Children s Hospitals, and the Division of Thoracic and Cardiovascular Surgery, University of Texas Medical School at Houston, Houston, TX. Accepted for publication Apr 1, 1977. Address reprint requests to Dr. Kyger, Texas Heart nstitute, PO Box 20345, Houston, TX 77025. focused on the morbidity and quality of life following correction. The sinus venosus atrial septal defect (SVASD) is an unusual variant that has occurred in approximately 10O/0 of our patients with an ASD. The SVASD is located high in the atrial septum where the superior vena cava (SVC) enters the right atrium, and is commonly associated with partial anomalous pulmonary venous return. Others have studied the late results of closure of secundum ASD with special attention to postoperative arrhythmias [8]. Repair of SVASD may be technically difficult because of its location adjacent to the SVC and sinus node and because of its frequent association with anomalous pulmonary venous drainage into the SVC. Because of the incidence of late arrhythmias, obstruction of the SVC, and incomplete repair, the question has arisen whether these defects should be closed [l]. We have reviewed our experience with this lesion in order to evaluate the early and late results of closure of SVASD, with special emphasis on arrhythmias. Between July, 1956, and December, 1974, 109 patients underwent closure of SVASD at our institutions. The 58 male and 51 female patients ranged in age from 1 to 72 years with a median age of 14 years at the time of operation. All patients underwent cardiac catheterization before operation. All defects were closed using total cardiopulmonary bypass. Six defects were closed primarily with an interrupted suture technique. Pericardial patches were used in 2 patients, and Dacron patch grafts were used to close the defects in the remaining 101 patients. n 6 patients the cavoatrial junction was enlarged with a pericardial patch so as to avoid obstruction of the SVC by the Dacron patch used to direct pulmonary venous return to the left atrium (Fig l). 44 0003-4975/78/002S-0109$01.25 @ 1978 by The Society of Thoracic Surgeons

45 Kyger et al: Sinus Venosus Atrial Septa1 Defect Pericardial patch enlarges atriocaval, junction G. - - - n 2 patients, small pulmonary veins draining high into the SVC were deliberately omitted from repair to avoid compromising the lumen of the SVC. Similar veins were ligated in 5 patients. A right upper lobectomy was performed in 1 patient because of a large anomalous vein draining too high into the SVC for patch diversion into the left atrium. Seven patients had associated cardiac procedures performed concomitantly with closure of the SVASD. One patient each required a single coronary artery bypass, a double coronary artery bypass, mitral and tricuspid annuloplasty, mitral valve replacement, aortic valve replacement, ligation of a patent ductus arteriosus, and closure of an associated foramen ovale ASD. Two patients had a large, persistent left SVC that necessitated cannulation, and another 2 patients had major coronary artery disease not amenable to coronary revascularization. Clinical follow-up data were available for review on 75 patients who returned for reexamination or from completed questionnaires directed to the patient and to the referring physician. The median follow-up time is five years. Preoperative and postoperative electrocardiograms were reviewed. nformation regarding clinical classi-

46 The Annals of Thoracic Surgery Vol 25 No 1 January 1978 fication, documented arrhythmia or symptoms of arrhythmias, medications, most recent electrocardiogram, murmurs, or other cardiac abnormalities was obtained by examination or from the questionnaire. The surgical result is classified excellent if the patient no longer has symptoms or requires medication, corresponding to New York Heart Association (NYHA) Functional Class. The result is considered good if the patient is noticeably improved (compared with preoperative status) but still requires cardiac medication or has occasional symptoms of arrhythmias; this corresponds approximately to NYHA Class 11. The result is classified fair if the patient considers himself or herself improved over the preoperative status yet remains symptomatic; this is roughly equivalent to Class 111. The result is considered poor if the patient has experienced no improvement since operation and still has major cardiac symptoms; these patients, however, are not necessarily in Functional Class V. Results All patients survived operation and were discharged from the hospital. One known late death occurred. Eleven years after closure of the SVASD this patient underwent mitral valve replacement for ruptured chordae tendineae and myxoid degeneration of the mitral valve. Nine Fig 2. Relationship betrueen patient age at the time of repair of sinus uenosus atrial septa1 defect and wentual clinical result. months after this second procedure the patient died suddenly in his sleep. Results of postmortem study revealed no apparent cause of death. The patient had experienced atrial fibrillation before the mitral valve replacement, but during operation he had converted to normal sinus rhythm, which he maintained until death. Of the 75 patients available for follow-up, 72% (54 patients) were classified as having an excellent result, 20% (15) had a good result, 5% (4) had a fair result, and 3% (2) had a poor result. The relationship between the patient s age at the time of repair and the eventual clinical result is shown in Figure 2. The median age for the entire series at the time of correction was 14 years. Patients experiencing excellent results underwent repair at a median age of 9 years. This differed markedly from the median age at operation of patients achieving good (47 years), fair (46 years), and poor (45 years) results. A few older patients also had good or excellent results after repair, but there was a clear correlation between poorer clinical results with increasing age at the time of closure of the SVASD. Fifteen patients (14%) had demonstrated evidence of atrial arrhythmia before operation. The arrhythmia was documented by electrocardiography in 12 of the 15. Three patients complained of intermittent episodes of palpitations that were probably intermittent atrial flutter or fibrillation. The relationship between the type of preoperative arrhythmia and the age of the patient is shown in Table 1. The bradyarrhythmias tended to occur in a younger age GOOD FAR POOR *... z 4.. 1. n W 2 r,,...... r........ *...........,,...... r

47 Kyger et al: Sinus Venosus Atrial Septa1 Defect Table 1. Preoperative Arrhythmias in 15 Patients Who Underwt7nt Closure of SVASD Type Low atrial (coronary sinus rhythm) Junctional First-degree AV block Premature atrial contractions Atrial tachycardia Atrial flutter Atrial fibrillation Palpitations AV = atrioventricular. No. of Age Patients (yr) 5 6, 8, 10, 40, 40 7 28 24 42 45 53, 73 26, 37, 43 group, and the tachyarrhythmias were more common in the older patients. The median age of patients suffering from preoperative arrhythmia was 38 years in contrast to the median of 14 years for the entire series. Postoperative arrhythmias were documented in 23 patients (21%) (Table 2). Two patients complained of palpitations postoperatively without electrocardiographic documentation. These were assumed to be paroxysmal atrial flutter or fibrillation. Of the 23 patients, 13 (56%) who had documented new atrial arrhythmias postoperatively reverted to normal sinus rhythm. Most reverted while still in the hospital convalescing from operation. One patient, a woman who was 49 years of age at time of operation, has severe symptoms and currently requires hospitalization an average of once per year for control of atrial fibrillation that was not present preoperatively. A pericardial patch (see Fig 1) was inserted into the cavoatrial junction in this patient, and she has persistent pulmonary hypertension (Table 3, Patient 7). Tachyarrhythmia has caused her difficulty for ten years. Thirty percent (2 of 6) of the patients whose cavoatrial junction was enlarged with a patch developed persistent new postoperative arrhythmias compared with an overall incidence of 14% (10 of 75) persistent new postoperative arrhythmias. Another patient, a 6-year-old boy, was discharged from the hospital and returned to a foreign country in complete atrioventricular dissociation but asymptomatic. According to information in a follow-up letter, seven years after operation the patient's heart was normal but he was having seizures, probably caused by a malformation of the central nervous system. There is a possibility that these are Stokes-Adams attacks. The median age of 18 patients with postopera- Table 2. New Postoperative Arrhythmias in 23 Patients Who Underwent Closure of SVASD Documented Return to Normal Persistent Sinus Rhythm Arrhythmia Type No. of Patients Age (yr) (No. of Patients) (No. of Patients) First-degree AV block 1 7... 1 Coronary sinus or 10 4, 4, 4, 4, 5, 8, 5 5 low atrial rhythm Nodal or junctional 6 10, 14, 27, 35 1, 3, 6, 11, 3 3" rhythm AV dissociation 1 27, 29 42 1... Atrial flutter 1 46 1... Atrial fibrillation 4 8, 18, 43, 55 3 lh Palpitations (not 2 26, 35...... documented) Total documented 23 13 10 "One patient may be having symptoms because of the arrhythmia. "Clinically significant. AV = atrioventricular.

48 The Annals of Thoracic Surgery Vol 25 No 1 January 1978 Table 3. Preoperative Pulmonary Hypertension in 7 Patieiits Who Underwent Closure of SVASD Patient No., Pulmonary Artery Pressure Age at (mm Hg) Arrhythmia Operation (yr), and Sex Preop Postop Preop Postop Clinical Result 1. 27, F 75 systolic 60125 2. 46, M Mean pressure 43 3. 35, F 60125 4. 42, F 76153 5. 43, F 55125 6. 42, M 94 systolic (mild mitral insufficiency) NA NA 100150, 3 Y' postop Normal 1 Y' postop NA 7. 49, F NA 72112, 7 yr postop Paroxysmal atrial tachycardia Palpitations Palpitations Occasional PVCS AF converted to NSR after MVR AF 10 yr later Acute pulmonary edema postop resolved; persistent pulmonary hypertension at follow-up exam 1 mo postop; no further follow-up Excellent at 12 yr Excellent at 9 yr Difficult postop course with 20 episodes of VF; improved symptomatically; no recent follow-up Slight DOE 10 yr postop Required MVR 11 yr later; died 9 mo later; fair result during interim Normal heart size; improved, but DOE; fair result NA = not available; PVC = premature ventricular contraction; VF = ventricular fibrillation; DOE = dyspnea on exertion; AF = atrial fibrillation; NSR = normal sinus rhythm; MVR = rnitral valve replacement. tive bradyarrhythmias is 8 years, whereas that of patients with postoperative tachyarrhythmias is 35 years. The median age of all patients experiencing postoperative arrhythmias is 14 years; this corresponds to the median age at operation of 14 years for the entire series. Six patients had markedly elevated pulmonary artery pressure before operation (see Table 3). All these patients were older when referred for operation, most being over 40 years of age. Of those available for follow-up, 2 patients have achieved an excellent result, 1 a good result, and another a fair result. Cardiac catheterization one month postoperatively revealed persistent pulmonary hypertension in l patient who was lost to follow-up. n another patient pulmonary hypertension had progressed to a dangerous level (100150 mm Hg) three years after operation; unfortunately, this patient was also lost to follow-up. The preoperative pulmonary pressures of a seventh patient who underwent car- diac catheterization at another institution, although unavailable for review, were believed to have been elevated. At recatheterization seven years postoperatively this patient had a pulmonary artery pressure of 72/12 mm Hg and no residual ASD. This patient has been hospitalized several times because of arrhythmia and, although improved compared to the preoperative status, is classed as having a fair result. Six other patients have been recatheterized at our institution. has shown a persistent left-to-right shunt. One 7-year-old girl has a persistent grade 2-3/6 systolic murmur and slight cardiomegaly. Findings of right ventricular hypertrophy, noted on preoperative electrocardiogram, have not resolved three years postoperatively. She has not been recatheterized but is assumed to have either a recurrent ASD or a residual anomalous vein draining to the right atrium.

49 Kyger et al: Sinus Venosus Atrial Septa1 Defect Seventy-six patients displayed abnormalities on one or more preoperative electrocardiographic recordings, including right ventricular hypertrophy, right axis deviation, or a right bundle-branch block pattern. Except for the 7-year-old girl mentioned previously, all patients whose electrocardiograms were available for review at least one year after operation showed signs of resolved right ventricular hypertrophy. The right bundle-branch block pattern tended to resolve itself more slowly, and a number of patients still exhibited this pattern on the last available electrocardiographic recording several years postoperatively. The morbidity associated with correction of SVASD is similar to that with other intracardiac procedures. One patient, a 50-year-old woman, suffered apparent air embolism resulting in transient hemiparesis and cerebral depression. She had a difficult postoperative course and required tracheostomy for prolonged ventilatory support. She made a complete neurological recovery and is asymptomatic fourteen years postoperatively. Another patient had several postoperative episodes of minor hemoptysis associated with infiltration of the right upper lobe. A small pulmonary vein draining high into the SVC had been ligated, apparently resulting in hemorrhagic pulmonary infarction. The chest roentgenogram of this patient eventually returned to normal. Other patients experienced the usual incidence of postoperative fever, atelectasis. and discomforts. Comment This review was undertaken to evaluate answers to three questions. Are the complications of closure of an SVASD such that repair should not be undertaken routinely? Are late arrhythmias caused by the surgical procedure, and are they disabling? Should repair be undertaken in older patients with elevated pulmonary pressure and advanced symptoms? We believe the answer to the first question is clearly provided in the data presented. There were no operative deaths and only 1 known late death. No instances of SVC obstruction occurred. Several of the patients who were lost to follow-up, especially those from foreign countries, may have died later. However, our experi- ence clearly contrasts with the reported natural history of unrepaired ASD, in which death is reported to occur at an average age of 36 [91 to 49 years [2]. With uncorrected ASD, the patient s last years are usually marked by progressive disability from cardiac arrhythmias and congestive heart failure. Follow-up of our teenage patients operated on up to twenty years ago revealed they have been spared this clinical course without severe surgical complications. Much has been mentioned in the literature of postoperative arrhythmias following closure of secundum ASD [4, 7, 111. However, previous reports have neither categorized the SVASD separately nor focused on the nature and type of arrhythmias present preoperatively as opposed to postoperatively. The effect of the patient s age on the type of preoperative or postoperative arrhythmia also has not been reported. There are no published randomized studies on occurrence of arrhythmia in operated as opposed to unoperated patients. Young [ll], in a thorough study, reported a 74% incidence of postoperative arrhythmia in children who underwent repair of secundum ASD. Eight percent (6 patients) of the children had nodal bradycardia that persisted for several years postoperatively, but half of these (3 patients) were known to have reverted spontaneously to normal sinus rhythm two, three, and nine years, respectively, after operation. n Young s patients who had persistent arrhythmias the incidence of SVASD was 33 YO (2 of 6) compared with 14% (10 of 71) among his entire patient population. This tends to support the common opinion that difficulties in rhythm are more frequent after repair of SVASD. This is generally assumed because of the proximity of the defect-and the required patch and suture line-to the sinus node [lo], to the internodal tracts [5], and to the blood supply to the sinus node [6]. n our series, fewer patients (10) were discharged from the hospital with a persistent new arrhythmia than those (15) who had an arrhythmia when they entered the hospital. Most of the bradyarrhythmias and low atrial rhythms present preoperatively tended to persist, whereas 2 of 7 preoperative tachyarrhythmias persisted postoperatively.

50 The Annals of Thoracic Surgery Vol 25 No 1 January 1978 Twenty-one patients in our series were over 40 years of age at the time of closure of the SVASD, and although the operative results in terms of final classification were not nearly so good as in younger patients, 90% (19 of the 21) believed they were markedly improved compared with their preoperative status. As previously noted, older patients tended to have tachyarrhythmias rather than bradyarrhythmias both before and after operation. n this age group, most patients with symptomatic tachyarrhythmias preoperatively will have persistent arrhythmia requiring medication postoperatively. Older patients with new tachyarrhythmias postoperatively usually will revert to sinus rhythm. Thus, problems with arrhythmias present no contraindication to operation in older patients with SVASD. We believe that older patients with SVASD should not be considered separately from patients with the more common secundum ASD and that they should undergo surgical repair with expected benefit in most cases, even though the patient may be in an advanced stage of decompensation. The presence of pulmonary hypertension is not a contraindication to operation unless the pulmonary resistance appears fixed at a level equal or close to systemic resistance and there is a major rightto-left shunt. Pulmonary hypertension increases the operative risk, however, and offers another reason for repairing these defects early. References 1. Clark EB, Roland JA, Varghese PJ, et al: Should the sinus venosus type ASD be closed: a review of the atrial conduction defects and surgical results in twenty-eight children (abstract). Am J Cardiol 35:127, 1975 2. Crosby RS, Griffith GC: nteratrial septal defect. Am Heart J 38:80, 1949 3. Gibbon JH: Application of a mechanical heart and lung apparatus to cardiac surgery. Minn Med 37:171, 1954 4. Hauston P, Parker EF, Arrants JE, et al: The adult atrial septal defect: results of surgical repair. Ann Surg 179:799, 1974 5. James TN: The connecting pathways between the sinus node and A-V node and between the right and left atrium in the human heart. Am Heart J 66:498, 1963 6. Kennel AJ, Titus JL: Thevasculature of the human sinus node. Mayo Clin Proc 47:556, 1972 7. Linde LM, Goldbert SJ, Siege1 S: The natural history of arrhythmias following septal defect repair. J Thorac Cardiovasc Surg 48:303, 1964 8. Reid JM, Stevenson JC: Cardiac arrhythmias following successful closure of atrial septal defect. Br Heart J 29:742, 1967 9. Roesler H: nteratrial septal defect. Arch ntern Med 54:339, 1934 10. Tany KSK, James TN, Effler DB, et al: njury of the sinus node in open heart operations. J Thorac Cardiovasc Surg 53:814, 1967 11. Young D: Later results of closure of secundum atrial septal defect in children. Am J Cardiol31: 14, 1973