Donald G. Ritter

Complete atrioventricular block in patients with atrioventricular discordance.

Although patients with atrioventricular (AV) discordance (corrected transposition) have abnormal conduction pathways and may spontaneously develop high-grade AV block, no quantitative assessment of the risk of this happening is available. We reviewed the data on 107 patients with AV discordance ages 2–76 years (mean 22 years) at follow-up. Eighty-two patients (77%) had a ventricular septal defect, 57 (53%) had pulmonary stenosis, 35 (34%) had tricuspid insufficiency and 24 (23%) had dextrocardia. Twenty-three patients (22%) had complete AV block. This condition was present in four patients at birth and developed in 19 patients at ages 4 months to 53 years (mean 18.1 years). Nine of these patients had permanent pacemaker implantation, four at the onset of complete block and five an average of 11 years later. Nine patients have AV block but no pacemaker. One patient died suddenly. Detailed data analysis showed that with increasing follow-up the risk of natural onset AV block continued at a rate of approximately 2% per year after diagnosis. The presence of an intact ventricular septum made AV block more likely. We conclude that patients with AV discordance are at risk of developing complete AV block throughout their lives. With increasing age, this risk is approximately constant and is probably not significantly increased by corrective or palliative surgery if acute surgical AV block does not occur. Pacemaker implantation is not necessary in some children with spontaneous AV block.

Long-term evaluation (12 to 22 years) of open heart surgery for tetralogy of fallot

Four hundred seventy-five patients underwent repair of tetralogy of Fallot from 1955 to 1964; 396 of these were hospital survivors and were followed up for 12 to 22 years. An excellent late clinical result was maintained by 87 percent of the 396 hospital survivors. A less than excellent result in the remaining 13 percent of hospital survivors was caused by late mortality in 7 percent (sudden death in 3 percent, death due to cardiac causes in 2 percnt and death due to noncardiac causes in 2 percent), required reoperation in 4 percent (mainly because of residual ventricular septal defect) and development of symptoms in 2 percent. Postoperative cardiomegaly (cardiothoracic ratio greater than 0.55) was observed in 60 (25 percent) of 246 patients who had a follow-up chest roentgenogram, and was more common among those who died late or remained symptomatic. Among the few patients with inadequate surgical relief of right ventricular hypertension who did not have transanular patch repair, the hypertension did not tend to decrease progressively, whereas it did decrease in patients who had patch repair. No late sudden deaths were encountered in 20 patients shown to have postoperative right bundle branch block plus left axis deviation (bifascicular block pattern). Pulmonary valve incompetence appeared to have relatively little harmful influence on the late result, causng cardiac disability in 1 percent of the patients and appeared to be the main contributing factor of postoperative cardiomegaly in 13 (5 percent) of the 246 patients who had a follow-up chest roentgenogram. Most late deaths and complicatins appeared within 2 years of operation, and accelerating deterioration in late results did not occur as the follow-up extended beyond 2 decades.

Peripheral venous contrast echocardiography

Contrast echocardiography is the technique of injecting various echo-producing agents into the bloodstream and, with standard echocardiographic techniques, observing the blood flow patterns as revealed by the resulting cloud of echoes. These techniques have only recently been utilized to evaluate various cardiac defects. Two physical properties of these agents characterize their usefulness: (1) clouds of echoes can be observed downstream as well as at the injection site, and (2) the echo-producing quality of these agents is completely lost with a single transit through either the pulmonary or the systemic capillary bed. Thus, detection of resultant echoes in both the venous and the arterial blood pool is indicative of abnormal shunting. In 60 patients with a spectrum of cardiac defects and a wide range in age of presentation, studies were made of (1) the feasibility of performing contrast echocardiography with superficial peripheral venous injections, and (2) the clinical usefulness of this relatively noninvasive technique in detecting and localizing intracardiac right ot left shunting. Most superficial peripheral veins could be utilized, and the resultant contrast echograms were reproducible and similar in quality to those obtained more central (caval) injections. Right to left shunts could be localized in the atrial, ventricular or intrapulmonary level. Characteristic flow patterns were also recognized for tricuspid atresia and common ventricle.

Long-term follow-up in the unoperated univentricular heart

Type A univentricular heart is a severe congenital cardiac defect; 50% of patients are dead 14 years after diagnosis, a death rate of 4.8% per year. Type C univentricular heart is even more lethal; 50% of patients are dead 4 years after diagnosis. Pulmonary stenosis did not protect either group of patients in terms of overall survival. Of the patients in class I or II at initial diagnosis, 34% of patients with type A and 12% of those with type C were in class III or IV or had died at follow-up. The most common causes of death were dysrhythmia, congestive heart failure and sudden and unexplained death.

Right and left ventricular function after the mustard procedure in transposition of the great arteries

Right and left ventricular function was assessed at cardiac catheterization in 33 asymptomatic patients 0.5 to 11 years (mean 4.6) after the Mustard operation for complete transposition of the great arteries. Ages at operation had ranged from 0.5 to 16 years (mean 4.2 years). Right ventricular function was assessed using videodensitometric determination of ejection fraction and ventricular volume data. Ventricular volumes were obtained by computerized video analysis utilizing Simpsons rule. The right ventricular ejection fraction was 37 +/- 11 percent (standard deviation), as assessed with videodensitometry and 42 +/- 10 percent as assessed with ventricular volume--both values less than normal (P less than 0.001). Right ventricular end-diastolic volume was significantly greater than normal (P less than 0.001) and averaged 202 +/- 70 percent, but left ventricular end-diastolic volume averaged only 125 +/- 53 percent. These observations after the Mustard operation indicate that right ventricular function is seriously decreased with relatively preserved left ventricular function. They support efforts for surgical correction utilizing the left ventricle as the systemic ventricle.

Late results after extracardiac conduit repair for congenital cardiac defects

Analysis of the late results in 352 patients surviving insertion of an extracardiac conduit before mid 1977 has provided a mean follow-up interval of 65 months. Three fourths of the patients remain in improved condition after operation. Serial measurements of transconduit gradient are available in 90. The median change was +7 mm Hg and the mean +21 mm Hg. Reoperation was required in 16 percent of patients (mortality rate 9 percent), most commonly (77 percent) because of progressive conduit stenosis, more commonly for transposition of the great arteries than for other types of anomalies, and more commonly after use of a homograft aortic conduit than a Hancock conduit. The side of the aorta on which the conduit was placed exerted no significant influence. The postrepair transconduit gradient did not affect the need for reoperation. Late survival was 95 percent at 1 year, 85 percent at 5 years, and 73 percent at 10 years and was significantly better (probability [p] less than 0.006) for patients with pulmonary atresia than for the others. The hospital mortality rate was highest, and the late mortality rate lowest, for children less than 5 years of age; the overall survival rate in this age group was lower. The postrepair right ventricular to left ventricular pressure ratio, together with age, was a principal prognostic indicator of late survival, being less good when more than 0.73. THe most frequent causes of late death were progressive congestive heart failure and sudden death.

Clinical, angiographic, and hemodynamic assessment of late results after Mustard operation.

SUMMARYSince 1974, late results of the Mustard procedure for correcting complete transposition of the great arteries have been evaluated by cardiac catheterization, electrocardiography, roentgenography, history, and physical examination of 48 Mayo Clinic patients. Of these, 15 were studied I month to 2 years postoperatively because of clinical deterioration. The other 33 had been asymptomatic but were asked to return for hemodynamic reevaluation one-half to 1I years postoperatively. Of the asymptomatic group, 19 underwent exercise electrocardiography prior to catheterization and eight performed supine exercise during catheterization. Cardiac catheterization proved the most effective mode of study.Significant cardiovascular abnormalities (caval obstruction, residual pulmonary stenosis, etc.) were found in 35 of the 47 patients -including 20 of the 33 who were asymptomatic. Eight of the symptomatic group and three of the others have died since this restudy. These poor results warrant renewed effort to devise better methods for correcting complete transposition.

Idiopathic hypertrophic subaortic stenosis in the young

Thirty-six young patients with idiopathic hypertrophic subaortic stenosis were studied. Twenty-seven patients were male and 9 female, and their mean age was 11.3 years (range 5 months to 20 years). Twenty-three patients (64 percent) had symptoms, the most common being dyspnea, angina and syncope. Diagnostic difficulties were encountered frequently in younger patients, especially those with right heart involvement, and in asymptomatic patients with murmurs suggestive of other cardiac defects. Patients were classified retrospectively into three groups on the basis of management. The first group consisted of 16 patients who were operated on; 4 of these patients died, 1 operatively and 3 suddenly late postoperatively (at 1.6, 2 and 10 years). The 12 long-term survivors (average follow-up period 6.2 years) have had good relief of symptoms. The second group comprised seven patients treated with propranolol; none of these died. The 13 patients in the third group received no therapy; 7 of these patients died, 6 suddenly and 1 from congestive cardiac failure. Idiopathic hypertrophic subaortic stenosis is a serious disorder that may present at any age and that may be difficult to diagnose. All patients with this disorder should be treated with propranolol; surgical intervention, although it does not totally abolish the risk of sudden death, appears to offer symptomatic improvement in most cases over a long-term follow-up period.

Systemic collateral and pulmonary artery stenosis in patients with congenital pulmonary valve atresia and ventricular septal defect.

Angiograms of 30 patients with congenital pulmonary valve atresia, ventricular septal defect, and large systemicpulmonary collateral arteries (SPCAs) were evaluated. All had aortography, 28 had SPCA arteriography, and 26 had right ventriculography. Seventeen (65%percnt;) of 26 patients had a right ventricular infundibulum, 23 (77%percnt;) had a pulmonary artery confluence, and five of the nine patients without a right ventricular infundibulum had a confluence. Sixty-six SPCAs of aortic origin were seen; 28 (42%percnt;) had narrowing and 21 patients (70%percnt;) had one or more narrowed SPCAs. Five patients had collaterals from internal mammary, subclavian or innominate arteries. Fourteen (47%percnt;) had hilar pulmonary artery stenosis. Of these 14 patients mild peripheral stenosis was demonstrated in five. Right aortic arch was present in 15 patients (50%percnt;). Complete angiographic delineation of pulmonary vasculature is an essential procedure for preoperative detection of pulmonary and SPCA stenoses in these patients.

Survival in atrioventricular discordance

SummaryLimited information is available concerning the long-term survival of patients with atrioventricular discordance, ventriculoarterial discordance, and two ventricles (corrected transposition). The long-term follow-up of 107 patients examined at the Mayo Clinic over a 30-year period between 1951 and 1981 was reviewed. Overall survival from the date of Mayo Clinic diagnosis was 70% at five years and 64% at ten years. Associated variables were analyzed for their effect on survival including sex, age at diagnosis, presence of ventricular septal defect, pulmonary stenosis, dextrocardia, left atrioventricular valve insufficiency, and complete heart block.There was no significant difference between those with and without a ventricular septal defect (VSD). Pulmonary stenosis was protective when a VSD was present but was not a significant predictor of long-term survival. The only variable that consistently correlated with decreased survival was left atrioventricular valve insufficiency (p<0.04 for univariate and stepwise Cox, andp=0.08 for multivariate analysis). A logistic model for survival after open-heart surgery failed to identify any significant variable.We conclude that the presence of left atrioventricular valve insufficiency in association with atrioventricular discordance significantly alters the long-term outcome. Atrioventricular valve replacement should be considered in such patients when insufficiency becomes hemodynamically significant.