Secundum Atrial Septa1 Defect and Mitral Valve Incompetence Gordon F. Murray, M.D., and Benson R. Wilcox, M.D.
ABSTRACT Mitral regurgitation associated with secundum atrial septal defect is described in 4 patients, each with a different mitral lesion: rheumatic valvular disease, congenitally cleft valve, subacute bacterial endocarditis with disruption of the chordae tendineae, and traumatic valve rupture. The pathological spectrum of mitral valve disease associatedwith atrial septal defect is reviewed, and it is suggested that structural abnormality of the mitral valve may accompanythe atrial septal defect. More general awareness of this association will allow the surgeon more accuracy in defining and repairing this rather unusual combination of lesions.
M
itral regurgitation associated with secundum atrial septal defect is not widely recognized [6], but the association is not unusual [4, 51. Insufficiency of the mitral valve was demonstrated in 6% of the patients with atrial septal defect during a thirteen-year period at the Mayo Clinic [ 161. Mitral regurgitation is a characteristic component of the ostium primum septal defect. Early heart failure due to the high-flow shunt and rapid deterioration when the mitral lesion is not corrected are common. Mitral valve incompetence associated with secundum atrial septal defect presents similar challenges and deserves emphasis. Clinical and hemodynamic features of the heart lesion may simulate a solitary atrial septal defect [7], the mitral lesion remaining undetected and uncorrected. This report emphasizes the spectrum of mitral disease associated with atrial septal defect by describing 4 patients with secundum atrial septal defect and mitral insufficiency secondary to four different lesions: rheumatic valvular disease, congenitally cleft valve, subacute bacterial endocarditis, and traumatic valve rupture.
Case Reports PATIENT 1
A 30-year-old black woman had been noted to have a heart murmur at the time of her first pregnancy in 1963. N o history of rheumatic fever was ascertained. Following her second uneventful pregnancy, in 1965, she experienced dyspnea on exertion and progressive early fatigability. Cardiac catheterization demonstrated a left-to-right shunt at the atrial level associated with severe mitral regurgitation. Right axis deviation was noted on the electrocardiogram. Operative exploFrom the Division of Cardiothoracic Surgery, University of North Carolina School of Medicine, Chapel Hill, N.C. Accepted for publication March 13, 1975. Address reprint requests to Dr. Murray, Division of Cardiothoracic Surgery, University of North Carolina School of Medicine, Box 7, Division of Health Affairs, Chapel Hill, N.C. 27514.
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Secundum ASD and Mitral Incompetence ration on November 1,1966, revealed a secundum atrial septal defect measuring 3 cm in its greatest dimension. The anterior cusp of the mitral valve was thickened but remained pliable. The posterior valve had rolled edges with thickening and foreshortening of its chordae. An annuloplasty corrected the mitral regurgitation, and the septal defect was closed with a Teflon patch. Subsequent pathological examination of the atrial appendage demonstrated Aschoff bodies. The patient enjoyed full activity for six years, but progressive dyspnea and fatigue developed in the year prior to her admission on July 1, 1973. Cardiac catheterization confirmed the clinical findings of severe mitral regurgitation. Mitral valve replacement was accomplished on July 31, 1973. The atrial septum was intact and the patch completely incorporated into the atrial septum. The valve was thickened and had markedly foreshortened chordae, obviating any plastic repair. The patient’s postoperative course was uncomplicated, and she was discharged on the eighth postoperative day. Two years after operation the patient enjoys normal activity without symptoms of congestive heart failure. PATIENT 2
A 28-year-old black woman had been known to have a grade 1/6 murmur for many years. She first noted shortness of breath and fatigability in 1969. Her symptoms progressed, and in 1972 physical examination detected atrial fibrillation and a grade 3/6 systolic murmur in the pulmonic area. One year later she was referred to North Carolina Memorial Hospital in severe congestive heart failure. At that time she was a thin, chronically ill woman with a blood pressure of 100/80 mm Hg and an irregular pulse rate of 80 per minute. A left parasternal heave was present, and there was fixed splitting of the second heart sound. A systolic ejection murmur was audible in the pulmonic area, and a soft pansystolic murmur at the apex and radiating to the axilla was heard. The liver was palpable 7 cm below the right costal margin. A chest roentgenogram showed enlargement of the heart and increased pulmonary vascularity. The electrocardiogram was very suggestive of an ostium primum atrial septal defect, evidenced by right bundlebranch block, left axis deviation, and P mitrale. An echocardiogram demonstrated paradoxical motion of the interventricular septum and normal mitral valve motion. Cardiac catheterization revealed a large shunt at the atrial level with a pulmonic-to-systemicflow ratio of 4: 1. The pulmonary artery pressure was 36/12 mm Hg and the mean left atrial pressure was 16 mm Hg. Angiography showed mild to moderate mitral regurgitation. On May 5, 1973, the patient underwent surgical exploration through a median sternotomy incision. A secundum defect was found with almost complete absence of the atrial septum. Inspection of the mitral valve revealed a 4 mm cleft in the anterior leaflet near the medial commissure. Chordae tendineae inserted on the free margin of the cleft. Valve competence was restored by direct suture of the cleft. The mitral annulus was not dilated. A large Dacron patch was used to close the defect in the atrial septum. Atrial fibrillation and flutter complicated the early postoperative course. Normal sinus rhythm was momentarily achieved by cardioversion, but atrial
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MURRAY AND WILCOX fibrillation recurred. Because she was asymptomatic with a ventricular response of 70 beats per minute, the patient was discharged on a regimen of digitalis. Spontaneous conversion to normal sinus rhythm occurred prior to her first clinic visit. Eighteen months following operation she is active with minimal fatigability and has no evidence of mitral regurgitation or residual left-to-right shunt on physical examination. PATIENT 3
A 32-year-old white woman had had a heart murmur for eighteen years but had been asymptomatic until August, 1972, when she experienced a febrile illness after a flulike syndrome. Examination showed two small splinter hemorrhages in the nailbed of her left index finger. A diagnosis of bacterial endocarditis was made at another hospital, and she was treated for seven weeks with intravenously administered antibiotics. Blood cultures were positive for Staphylococcus epidermidis. Following discharge the patient noted ankle edema and easy fatigability. She responded to digitalis and diuretic therapy but was referred to North Carolina Memorial Hospital on January 7, 1972, because of progressive cardiac enlargement. Physical examination revealed a young woman in no distress with a blood pressure of 90/60 mm Hg and a regular pulse rate of 76 beats per minute. The jugular venous pulse showed prominent “a” and “v” waves. A parasternal heave was present with a sustained left ventricular apical lift. A precordial systolic thrill was palpable, and a grade 5/6 coarse pansystolic murmur was audible at the left sternal border radiating to the axilla. A chest roentgenogram demonstrated biventricular enlargement and pulmonary plethora (Fig. 1A). Right ventricular hypertrophy and right axis deviation were noted on the electrocardiogram. An echocardiogram illustrated paradoxical motion of the interventricular septum and normal excursion of the mitral valve. Cardiac catheterization findings included a significant oxygen step-up at the atrial level and a left-to-right shunt of 14.6 liters per minute. Pulmonary hypertension (60/30 mm Hg) was noted, with “v” waves of 50 mm Hg in the left atrium. Angiography demonstrated severe mitral regurgitation with no ventricular deformity and a left-to-right shunt at the atrial level. Operation was performed on January 29, 1972. Intracardiac palpation prior to bypass revealed a 4 cm secundum atrial septal defect and marked insufficiency of the mitral valve. Inspection of the valve showed rupture of two chordae tendineae along the lateral aspect of the aortic leaflet. The flail leaflet was plicated with two mattress sutures and the lateral and medial commissureswere narrowed. The valve appeared competent, and the atrial septal defect was closed with a patch of knitted Dacron material. Mean left atrial pressures obtained in the operating room following repair were 9 mm Hg with a “v” wave of 13 mm Hg. Nearly three years after operation the patient enjoys full activity as managing editor of a daily newspaper. Residual mitral insufficiency is evidenced by a soft systolic murmur at the apex; however, the heart size has dramatically improved (Fig. 1B) and she is asymptomatic. 138
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FIG. I . (Patient 3 . ) ( A ) Chest roentgenogram taken February I I , 1973, shows biventricular enlargement and pulmonary plethora. (B) After mitral valvuloplasty and closure of the atrial septal defect, the roentgenogram obtained November 15, 1974, shows reduction in heart size. PATIENT 4
A 12-year-old white girl was well until she fell beneath her horse in late January, 1973. She was observed in another hospital for three days and no cardiac abnormality was noted. During the next two months she developed easy fatigability, palpitations, and increased shortness of breath with exercise. On March 8, 1973, the patient was admitted to North Carolina Memorial Hospital in profound congestive heart failure. Physical examination revealed a small, thin girl with a bounding precordium. A grade 3/6 holosystolic murmur was heard at the apex and radiating to the left axilla. A grade 2/6 systolic murmur was present in the pulmonic area, and a diastolic rumble was audible at the apex. The first heart sound was widely split, and an S3gallop was heard. T h e liver was felt 9 cm below the right costal margin. A chest roentgenogram demonstrated massive cardiac enlargement with increased pulmonary vascularity and small bilateral pleural effusions (Fig. 2A). T h e electrocardiogram showed right axis deviation, right ventricular hypertrophy, and atrial flutter with variable conduction. An echocardiogram revealed paradoxical motion of the interventricular septum, and the amplitude of the mitral D-E excursion was increased. Cardiac catheterization demonstrated a large left-toright shunt at the atrial level and elevated pulmonary and left atrial pressures. A left ventricular angiogram showed moderate mitral regurgitation. Operation was performed on April 9, 1973. A ragged, linear tear in the midportion of the aortic leaflet of the mitral valve was seen through a 3 x 4 cm secundum atrial septal defect. Unlike the congenitally cleft valve in the second patient, no chordae were attached to the margins ofthe valve rent. The torn leaflet was repaired with a horizontal mattress suture, and a posteromedial annuloplasty was performed. T h e atrial septal defect was closed with a knitted Dacron patch. Hemodynamic studies done in the operating room after repair revealed no shunt and normal left atrial pressures. Except for intermittent atrial flutter the postoperative course was unremark-
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FIG. 2 . (Patient4 .) ( A ) Chest roentgenogram on May25,1973, shows massive cardiac enlargement with increased pulmonary vascularity and small bilateral pleural effbions. ( B ) Postoperative roentgenogram taken February 8 , 1974, shows improvement.
able. One year after operation the child has returned to full activity. A murmur of mitral insufficiency persists, but both the heart size and pulmonary vascularity are decreased on chest roentgenogram (Fig. 2B).
Comment T h e classic description of mitral valve disease associated with atrial septal defect was recorded in 1916 by Lutembacher [20]. He described a patient with interatrial communication of the foramen ovale type and mitral stenosis, presumably of rheumatic origin. The syndrome is now widely recognized [32], and Demos and associates [ 101 have emphasized that both mitral stenosis and insufficiency may occur with rheumatic mitral valve involvement associated with atrial septal defect. The first patient described here, who had severe mitral regurgitation and a large atrial septal defect, had no history of rheumatic disease but Aschoff bodies were demonstrated in the excised atrial appendage. It has been suggested that the interatrial communication in such cases may be due to incompetence of the foramen ovale secondary to dilation of the high-pressure left atrium [22]. A prosthetic patch was required to close the large secundum defect in each of the 4 patients described in this report, so all appeared to have more than a dilated patent foramen ovale. Congenital mitral insufficiency due to a cleft in the anterior leaflet of the mitral valve is usually associated with the ostium primum septal defect or persistence of the atrioventricular canal. Cleft of the septal mitral leaflet with a large atrial septal defect was first reported by Hara and Char [ 151in 1966 in a 4-year-old girl. Subsequently, the combination of cleft mitral valve and an atrial septal defect has been noted in several case reports [26, 29, 311. Cohn and associates [71, in describing 5 patients with atrial septal defect and congenitally cleft valve, encouraged routine evaluation of mitral valve competence during cardiopulmonary
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Secundum ASD and Mitral Incompetence bypass. The valve lesions are characterized by constant insertion of normal chordae tendineae into the cleft’s free edge, as noted in our Patient 2. The cleft may occur in the anterior [15, 29, 311 or posterior [7, 241 mitral leaflet. Primary suture repair of the cleft has been possible in cases of uncomplicated congenital mitral cleft [ 15,29,31]. Sugg and Fox [361 in 1967 described a singular patient with atrial septal defect and insufficient mitral valve tissue who required prosthetic replacement. Cohn and co-workers [7] sutured the mitral clefts in 4 of their patients with good results; a fifth patient with endocarditis required valve replacement. Surgical procedures for repair of the congenitally cleft leaflet have recently been described by McEnany and colleagues [24]. Billowing posterior mitral leaflet syndrome associated with atrial septal defect must be added to the differential diagnosis of congenital mitral regurgitation. The frequency of this association has been confirmed in several recent reports [2, 14, 17,23,30,37]. It has been stressed that midsystolic click and late systolic murmur must be sought in the presence of an atrial septal defect and that atrial septal defect not be overlooked in the mitral valve prolapse -click syndrome. Infective endocarditis may complicate the billowing posterior mitral leaflet syndrome [ 19, 351, and antibiotic prophylaxis is necessary. Valve replacement rather than repair is the surgical treatment of choice for severe regurgitation in the floppy valve syndrome [6, 8, 121. Bacterial endocarditis is a rare complication of atrial septal defect [13]. However, preexisting damage or abnormality of the mitral valve may increase the susceptibility of patients with atrial septal defect to bacterial endocarditis [9, 18, 351. Recently, Okada and colleagues [27] reported significant structural changes in the mitral valve in patients with isolated atrial septal defect. The mitral leaflets are commonly thickened, especially about the posterior commissure, and there may be fibrosis and fusion of the chordae tendineae. These authors suggest that the mitral changes are secondary to altered flow patterns associated with the atrial septal defect. Danilowicz and colleagues [9] have speculated that this acquired mitral valve lesion may account for some instances of endocarditis credited to Lutembacher’s syndrome. Mitral valve damage secondary to the large left-to-right shunt at the atrial level may have contributed to the development of endocarditis and chordae tendineae rupture in 1 of our patients (No. 3). Rupture of the mitral valve leaflet associated with atrial septal defect (Patient 4) has not been previously reported. Two patients with papillary muscle rupture and associated atrial septal defect have been noted [25], but clinical data were not given. The mitral valve with an underlying structural abnormality is probably more susceptible than a normal valve to injury [33]. The presence of the atrial septal defect again suggests acquired change in the valve, as described by Okada and colleagues [271. Mitral valve disruption due to blunt trauma to the chest is otherwise a rare occurrence [341. In a postmortem review of 546 nonpenetrating injuries of the heart, Parmley and associates [281 found no isolated case of mitral valve injury. Reported injury of the mitral valve very rarely involves the valve directly [251; more frequently noted is rupture of a papillary muscle [31 or of chordae tendineae [l]. VOL. 20, NO. 2, AUGUST, 1975
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MURRAY AND WILCOX The first successful repair ofa torn mitral leaflet was reported by McLaughlin and colleagues [25] in 1964. They employed direct suture of the tear and posteromedial annuloplasty, similar to our procedure. Plastic repair is the surgical technique of choice in these circumstances. Opinion is more diverse regarding the surgical treatment of disrupted chordae tendineae. Some recommend routine prosthetic valve replacement [33], whereas others emphasize the value of plastic reconstruction [2 11. The ultimate decision regarding surgical technique usually cannot be determined until the time of operation.
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