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Biomedical subjects

D G Ritter

Publications and source records attributed to D G Ritter.

At least 37 records · Page 2Linked to original sources
PubMed1984

Long-term follow-up after palliative operation for univentricular heart.

Data are presented from 84 patients (45 males, 39 females), aged 6 days to 25 years (mean 10 years), with univentricular heart who underwent a palliative surgical procedure. The mean follow-up period was 5 years (range 1 month to 25 years). Of the 84 patients, 33 died and 51 are alive. The survivors were 1.5 to 41 years (mean 15). Systemic pulmonary artery shunts alone were performed in 43 patients, pulmonary artery banding in 15, and a combination of procedures in 26. Five years after diagnosis, 70% of patients with type A and 54% with type C univentricular heart were alive, with no statistical difference in survival between the patient groups. Because of the high attrition rate in these patients despite palliation, further attempts to perfect corrective surgery appear justified.

Adolescent↗
PubMed1984

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.

Aged↗
PubMed1984

Results of the Damus-Stansel-Kaye procedure for transposition of the great arteries and for double-outlet right ventricle with subpulmonary ventricular septal defect.

From 1975 through 1982, the Damus-Stansel-Kaye procedure was performed on 20 patients with complete transposition of the great arteries (TGA) and on 4 with double-outlet right ventricle (DORV) and subpulmonary ventricular septal defect (VSD). The patients ranged from 6 days to 20 years old (median age, 13 months). Associated anomalies included atrial septal defect (24 patients), VSD (14), and others (25). Thirteen patients had had palliative operations previously. Of the 14 hospital deaths (58%), 13 occurred among the 17 patients with one or more risk factors: age less than 18 months, weight less than 10 kg, and left ventricular peak systolic pressure less than 75% of systemic pressure. Follow-up ranged from 12 to 87 months (mean, 51 months). One patient died of cardiac failure two years postoperatively, and 2 required conduit replacement at 40 and 50 months because of stenosis. All 9 survivors are free from major symptoms. The Damus-Stansel-Kaye repair is most suitable for patients with TGA or DORV with subpulmonary VSD who are older than 18 months, weight more than 10 kg, and have a "prepared left ventricle," and whose coronary artery anatomy precludes transplantation.

Adolescent↗
PubMed1984

Functional single ventricle: cardiorespiratory response to exercise.

The cardiorespiratory response to exercise was measured in 27 children with functional single ventricle. All 27 patients had a significant reduction in exercise time, work performed, maximal exercise heart rate, maximal oxygen uptake and systemic arterial blood oxygen saturation. The reduction in exercise performance increased with increasing age of the patients. All patients ventilated excessively at rest and during exercise. This study documented the precise level of exercise intolerance in patients with functional single ventricle. The progressive deterioration in exercise performance with increasing patient age may lend credence to the concept that operation for physiologic correction of functional single ventricle should be considered during or before adolescence.

Adolescent↗
PubMed1984

Functional assessment of the Fontan operation: combined M-mode, two-dimensional and Doppler echocardiographic studies.

Combined M-mode, two-dimensional and Doppler echocardiographic studies were used to assess the postoperative status of 33 patients who had undergone the modified Fontan procedure. Twenty-four patients had surgical repair with use of a simple direct right atrium to pulmonary artery anastomosis. The remaining patients had repair with use of a prosthesis or associated Glenn shunt. Twenty-seven patients were studied early in the postoperative period (2 months or less) and the remaining patients were studied up to 6 years postoperatively. A total of 36 examinations were performed. Of the 33 patients, 13 had tricuspid atresia, 12 had double inlet left ventricle with hypoplastic right ventricular outlet chamber and 8 had complex lesions with atrioventricular canal, double outlet right ventricle or a hypoplastic ventricle. Postoperative assessment by M-mode and two-dimensional echocardiography demonstrated normal or mildly reduced ventricular function (ejection fraction greater than 40%) in 22 patients. In 24 patients, a "normal" flow pattern was observed in the pulmonary artery by pulsed Doppler echocardiography, with predominant diastolic flow and accentuation by atrial systole somewhat similar to the venous flow pattern observed in the superior vena cava. "Abnormal" flow patterns (disorganized systolic flow, absence of atrial waves and little or no increase with inspiration) were observed in nine patients with reduced ventricular function or residual shunt. Continuous wave Doppler study also demonstrated mild dynamic subaortic obstruction in two patients. Combined pulsed and continuous wave studies showed atrioventricular valve insufficiency in 10 patients. Follow-up studies revealed a satisfactory clinical course in most patients. Three patients died approximately 4 to 8 months after their Fontan operation.

Adolescent↗
PubMed1984

Reoperation for obstructed pulmonary ventricle-pulmonary artery conduits. Early and late results.

Obstruction of pulmonary ventricle-pulmonary artery conduits can result from neointimal peel formation or valvular degeneration and calcification. To determine the risks and outcome of reoperation, we reviewed the records of 100 consecutive patients who had replacement of severely stenotic pulmonary ventricle-pulmonary artery conduits. At reoperation, the 70 male and 30 female patients had a mean age of 13.3 +/- 4.8 years. During operation, 37 homografts, 62 Dacron grafts with integral xenograft valves, and one nonvalved conduit were replaced with valved (80) or nonvalved (17) prostheses. The mean transconduit pressure gradient decreased from 81 +/- 26 mm Hg preoperatively to 7 +/- 8 mm Hg postoperatively (p less than 0.01). Concomitant cardiac valve replacement was performed in seven patients, and residual ventricular septal defect closure was accomplished in 28. Operative mortality (less than 30 days) was 7%, but there were no deaths among the 47 patients who had no associated defects. At 3 and 5 years postoperatively, probability of survival among patients dismissed from the hospital was 94% +/- 3% and 86% +/- 6%, respectively. In our experience, risk of reoperation for conduit obstruction alone is low, so that the effect of graft failure on overall survival is minimized.

Adolescent↗
PubMed1983

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.

Actuarial Analysis↗
PubMed1983

Permanent endocardial pacing in pediatric patients.

Improved technology with smaller pulse generators and passive and active fixation endocardial lead systems has the potential for facilitating safe, reliable pacing in pediatric patients. Of 18 pediatric patients (mean age 11.1 years) undergoing permanent transvenous cardiac pacing during the period April, 1977, to January, 1981, two (11%) required reoperation during a mean follow-up of 18.8 months. Satisfactory stable pacing was maintained even in patients with dual-chamber pacing systems and in patients with transposition of the great vessels in whom a lead was placed in a morphologically left atrium. This reoperation rate of 11% contrasts with a reoperation rate of 32% in 22 pediatric patients (mean age 8.7 years) who underwent placement of ventricular-demand epicardial pacing systems during the same period. In our experience, transvenous endocardial pacing is the preferred route in pediatric patients because of the improved lead system survival and the potential for atrial or atrioventricular sequential pacing.

Adolescent↗
PubMed1982

Cardiac-catheterization and cardiac-surgical facilities: use, trends, and future requirements.

Cardiac catheterizations and cardiac operations were evaluated in the population of Olmsted County, Minnesota, from 1973 through 1980, and trends in this region were compared with nationwide trends based on data from several sources. The rates of coronary arteriography and coronary-artery bypass operations in Olmsted county have increased over time, but overall, the rates of catheterization and operation appeared to be leveling off. For the country as a whole, the data appear to show similar trends, but there are wide differences among regions in the rates of operation and catheterization. In 1980 40 per cent of hospitals with cardiac-catheterization laboratories and 55 per cent of those with facilities for open-heart surgery were doing fewer than the suggested minimum numbers of these procedures necessary to achieve optimum results. The data support the view that further growth in the number of cardiac centers should be avoided. We believe there is a need for continued evaluation of the use of cardiac services if quality is to be protected and costs controlled.

Adult↗
PubMed1982

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.

Adolescent↗
PubMed1982

Two-dimensional echocardiographic assessment of dextrocardia: a segmental approach.

Two-dimensional echocardiography was used in the prospective evaluation of 40 patients with the clinical diagnosis of dextrocardia. A segmental analysis of the situs, connections, ventricular anatomy, and chamber positions was utilized for a complete diagnostic assessment. An adequate examination was possible in 33 of these patients; the findings were confirmed by cardiac catheterization and angiography in 31 patients and at operation in 26. Use of the location of the liver and the drainage of the hepatic veins and inferior vena cava allowed atrial visceral situs to be defined in 33 patients (solitus 21, inversus 9, and ambiguous 3). Pulmonary venous connections were correctly identified in 27. In 33 patients, atrioventricular (AV) and ventriculoarterial connections and ventricular anatomy were correctly predicted. Twenty patients had 2 separate well-developed ventricles. Ventriculoarterial connections were determined correctly in all 20 patients: concordant in 5, discordant in 6, double-outlet right ventricle in 5, and single-outlet right ventricle (pulmonary atresia) in 4. In 16 patients a ventricular septal defect was correctly identified. In the remainder the ventricular septum was intact. Thirteen patients had univentricular heart: 8 had 2 AV valves (double-inlet ventricle) 3 had common AV inlet, and 2 had atresia of 1 AV connection. Two-dimensional echocardiography allowed the accurate assessment of complex congenital heart defects associated with dextrocardia. Utilizing a segmental approach, one can correctly predict atrial-visceral situs, ventricular morphology and situs, and AV and ventriculoarterial connections.

Adolescent↗
PubMed1982

Partial atrioventricular canal defect in adults.

Between March 1955 and March 1981, 52 adult patients (age 20 years or older) with partial atrioventricular canal (PAVC) were examined at the Mayo Clinic. Forty patients were in New York Heart Association (NYHA) functional class I or II. The ECG showed right bundle branch block with left-axis deviation in 48, first-degree atrioventricular block in 33 and atrial fibrillation in nine. Preoperative catheterization was done in 37 patients; the mean pulmonary resistance index was 2.8 U.m2, and the mean pulmonary-to-systemic flow ratio was 3.0. Forty-seven patients underwent operation; two required mitral valve replacement. There were three operative deaths (6.4% operative mortality) and two late deaths. All surviving patients were in NYHA class I or II. No patient required subsequent permanent pacemaker implantation. We conclude that repair of PAVC in adults may be performed at low risk and may improve patient longevity and functional status.

Adult↗
PubMed1982

Serologic survey for canine distemper and infectious canine hepatitis in wolves in Alaska.

Sera from 57 wolves (Canis lupus) in three areas of Alaska were evaluated for evidence of previous exposure to infectious canine hepatitis virus (ICHV) and canine distemper virus (CDV). Fifty-four sera (94.7%) were positive for ICHV exposure and four (7%) were positive for CDV exposure. All four CDV-reacting wolves also had titres to ICHV. The relatively common occurrence of ICHV exposure may be due to the greater resistance of ICHV to chemical and physical agents and its transmissibility via the urine of infected animals. The ICHV titres observed could indicate enzootic pathogenic ICHV, or exposure to the mildly pathogenic vaccine strain of CAV-1 through contact with the urine of domestic dogs. If CAV-1 is the original source of exposure, the titres could represent an ICHV-protected wolf population.

Adenoviruses, Canine↗
PubMed1982

Successful repair of coexisting double-outlet right ventricle and two-chambered right ventricle.

Double-outlet right ventricle (DORV) and two-chambered right ventricle (TCRV) are both uncommon cardiac malformations; even more rare is the coexistence of these lesions. This communication describes the first two patients in whom this unusual combination of anomalies was recognized during life and successfully repaired with the aid of extracorporeal circulation. Late results in both patients are excellent.

Child, Preschool↗
PubMed1981

Double-outlet right ventricle: wide-angle two-dimensional echocardiographic observations.

M-mode echocardiographic delineation of double-outlet right ventricle (DORV) has relied primarily on the demonstration of mitral-semilunar valve discontinuity--a feature that requires an interpretation of spatial anatomic relationships. Thirty-six patients with DORV were examined by wide-angle real-time two-dimensional echocardiography. Anatomic diagnosis was established by surgery in 28 patients and by angiography alone in eight. Typical two-dimensional echocardiographic features were (1) parallel orientation and origin of both great arteries from the anterior right ventricle, (2) mitral-semilunar valve discontinuity demonstrated on parasternal long-axis scans by the presence of muscular conus separation, and (3) absence of left ventricular outflow other than a ventricular septal defect. This technique also allows better recognition of spatial orientation of the great arteries and the position of the ventricular septal defect relative to the great arteries. An unexpected finding was a high incidence of atrioventricular valvular anomalies, particularly annular override or abnormal chordal attachments (straddling) (eight patients), isolated cleft of the mitral valve (two patients), and complete atrioventricular canal (five patients). Thus, these two-dimensional echocardiographic findings have allowed improved noninvasive recognition of DORV and the demonstration of associated anomalies that previously were unrecognized preoperatively.

Adolescent↗