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Biomedical subjects

J M Kratz

Publications and source records attributed to J M Kratz.

At least 19 recordsLinked to original sources
PubMed1992

Atrioventricular pacing in congenital heart disease.

We have attempted to optimize cardiac performance in patients with congenital heart disease requiring artificial pacing by using pacemakers capable of both sensing and pacing both the atrium and the ventricle (DDD). We reviewed our results with 88 patients receiving DDD devices to determine the safety and dependability of these devices in children. Age ranged from 1 hour to 25 years. Endocardial leads were used in 68 patients, whereas epicardial leads were used in 20 patients. Previous cardiac procedures had been done in 30 patients. There were nine deaths but none due to pacemaker malfunction. Endocardial leads functioned better than epicardial leads. Ninety-eight percent of patients with endocardial leads and 62% of patients with epicardial leads were maintained in the DDD mode. Complications were infrequent and all were corrected without long-term sequelae. The DDD mode may offer considerable benefits to children who require artificial pacing. Our data allow us to conclude that most children can be paced safely and dependably in the DDD mode.

Adolescent↗
PubMed1992

Retrograde versus antegrade cardioplegia: impact on right ventricular function.

Retrograde cardioplegia administered through the coronary sinus has several documented advantages over antegrade cardioplegia but has been thought to provide inadequate right ventricular myocardial protection. We prospectively compared the effects of retrograde and antegrade cardioplegia on right ventricular performance in patients undergoing myocardial revascularization. Two groups of similar age, extent of disease, and preoperative left ventricular ejection fraction received retrograde (n = 16) or antegrade (n = 14) crystalloid cardioplegia. A right ventricular rapid-response thermistor catheter, previously developed and validated in our institution, was used to measure right atrial pressure, pulmonary artery pressure, right ventricular ejection fraction, end-diastolic volume index, and stroke volume index before bypass (baseline) and at several intervals after bypass. There were no differences in cross-clamp time, heart rate, cardiac enzymes, inotrope requirements, or arrhythmias between the two groups. Right ventricular parameters were equivalent in both groups at all time intervals except 30 minutes after bypass, at which time right ventricular end-diastolic volume index was lower (80 +/- 6 versus 93 +/- 6 mL/m2; p less than 0.05) and right ventricular stroke volume index was higher (35 +/- 3 versus 29 +/- 2 mL/m2, p less than 0.05) in the retrograde group compared with the antegrade group, indicating better right ventricular function with retrograde cardioplegia early after bypass. In both groups, right ventricular end-diastolic volume index was higher than baseline (p less than 0.05) during the first 4 hours after bypass. No other important differences were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Use of a combined right ventricular ejection fraction-oximetry catheter system for coronary bypass surgery.

OBJECTIVE: To evaluate the reproducibility and accuracy of a new pulmonary artery catheter system that provides both right ventricular ejection fraction and continuous venous oxygen saturation monitoring. DESIGN: Criterion standard study. SETTING: University medical center. PATIENTS: A consecutive sample of ten patients undergoing elective coronary artery bypass surgery provided informed consent for the study. Exclusion criteria included emergency surgery or clinically important preoperative tricuspid regurgitation as assessed by echocardiography. None of the patient sample was excluded. MEASUREMENTS: Catheter-derived mixed venous and arterial oximetry data were compared with simultaneous values obtained using conventional laboratory cooximetry methods. Measurements were performed before cardiopulmonary bypass and intermittently up to 48 hrs after cardiopulmonary bypass. The variability of cardiac output and computed right ventricular ejection fraction was also assessed concurrently with the oximetry analysis. RESULTS: A significant correlation was observed for mixed venous oxygen saturation between catheter-derived and laboratory cooximetry data (r2 = .81, p < .01). Similarly, arterial oxygen saturation values obtained from pulse oximetry and laboratory values were significantly related (r2 = .81, p < .01). The coefficient of variation for each set of five repeated measurements for cardiac output was 8%, and for computed right ventricular ejection fraction, it was 16%. CONCLUSIONS: The combined catheter system provides the means to monitor both mixed venous oxygen saturation and right ventricular ejection fraction. These data provide a reliable and detailed assessment of cardiopulmonary function that should prove beneficial in the critical care setting.

Aged↗
PubMed1992

Cardiac pacing in neonates, infants, and preschool children.

A series of 37 children < 5 years old at pacemaker implant were followed from 1 to 105 months. Five of 37 patients required reoperation for battery depletion while two required reoperation for exit block of epicardial ventricular leads. Each patient paced in the DDD or AAI mode was still in the original mode at the end of follow up.

Cardiac Pacing, Artificial↗
PubMed1992

Mitral valve replacement with and without chordal preservation in patients with chronic mitral regurgitation. Mechanisms for differences in postoperative ejection performance.

BACKGROUND: Standard mitral valve replacement (MVR) in patients with chronic mitral regurgitation consistently results in a decrease in postoperative left ventricular (LV) ejection performance. This fall in ejection performance has been attributed, at least in part, to unfavorable loading conditions imposed by the elimination of the low-impedance pathway for LV emptying into the left atrium. In contrast to standard MVR in which the chordae tendineae are severed, however, MVR with chordal preservation (MVR-CP) does not usually decrease LV ejection performance despite similar removal of the low-impedance pathway. The purpose of the present study was to define the mechanisms responsible for this discordance in postoperative ejection performance between MVR with and without chordal preservation. METHODS AND RESULTS: Echocardiography and sphygmomanometer blood pressures were obtained in 15 patients with pure chronic mitral regurgitation before and 7-10 days after mitral valve surgery. These measurements were used to calculate ventricular volume, wall stress, and ejection fraction. Seven patients underwent MVR with chordal transection (MVR-CT), and eight patients underwent MVR-CP. MVR-CT resulted in no postoperative change in LV end-diastolic volume, a significant increase in LV end-systolic volume, a significant increase in end-systolic stress, from 89 +/- 9 to 111 +/- 12 g/cm2 (p < 0.05), and a significant decrease in ejection fraction, from 0.60 +/- 0.02 to 36 +/- 0.02 (p < 0.05). In contrast, patients who underwent MVR-CP had a significant decrease in LV end-diastolic and end-systolic volumes. End-systolic wall stress actually fell from 95 +/- 6 to 66 +/- 6 g/cm2 (p < 0.05), and ejection fraction was unchanged (0.63 +/- 0.01 before and 0.61 +/- 0.02 after mitral valve surgery) instead of reduced. CONCLUSIONS: MVR-CT resulted in a decrease in ejection performance caused in part by an increase in end-systolic stress, which in turn increased end-systolic volume. Conversely, MVR-CP resulted in a smaller LV size, allowing a reduced end-systolic stress and preservation of ejection performance despite closure of the low-impedance left atrial ejection pathway.

Chordae Tendineae↗
PubMed1991

Prospective, randomized trial of palliative treatment for unresectable cancer of the esophagus.

To evaluate the best method of palliation for obstructing nonresectable squamous cell carcinoma of the mid or distal esophagus, 27 patients were prospectively randomized to one of three treatment arms: (1) esophageal intubation with an Atkinson tube (AT, 10 patients), (2) esophageal intubation followed by radiation therapy (AT/RT, 8 patients), and (3) endoscopic laser therapy followed by irradiation (L/RT, 9 patients). Pretreatment characteristics were similar in the three groups. There was no procedure-related mortality. There were eight total complications related to the tube and none related to laser treatment (p = 0.02). Mean survival was 119 days in the AT group, 72 days in the AT/RT group, and 169 days in the L/RT arm (p = not significant). Quality of survival was most dependent on swallowing ability, and the swallowing score increased by 2.3 units in the AT group, 1.8 units in the AT/RT group, and 1.4 units in the L/RT group (p = not significant). Adding RT to laser therapy significantly increased time in treatment (mean, 38.7 days) when compared with the AT group (mean, 12.5 days) (p less than 0.001). However, only 1 patient required repeat laser ablation. It is concluded that AT and L/RT result in good palliation as measured by relief of dysphagia and survival time. However, morbidity of AT is significantly greater than that of L/RT. Laser and radiation therapy with a reduced total dosage of RT or with a change in fractionation schedule to limit treatment time is the preferred method of palliation.

Adult↗
PubMed1991

Cardiac surgery for patients maintained on chronic hemodialysis.

This study confirms and extends the available information about cardiac surgery in patients with chronic renal failure. With appropriate precautions, CABG and valve repair can be carried out in these patients without significant increase in operative mortality or morbidity as compared to patients with normal renal function. However, these patients remain susceptible to accelerated atherosclerosis in native vessels as well as bypass grafts and to complications (thromboembolism, infection) of prosthetic valves. Accordingly, while these patients are often significantly improved as a result of their cardiac surgery, long term outlook is guarded.

Adult↗
PubMed1990

Forceps extraction of permanent pacing leads.

With the advent of tined transvenous cardiac pacing leads, the complete extraction of pacing leads in the treatment of an infected cardiac pacing system has become increasingly difficult. A method is described for the extraction of permanent pacing leads from the heart using alligator forceps inserted transvenously through the right internal jugular vein, grasping the lead near its insertion point in the cardiac muscle.

Electrodes, Implanted↗
PubMed1990

Programming eccentricities of an activity sensing pacemaker.

The Activitrax rate responsive pacemaker system has enjoyed wide popularity but minor engineering eccentricities have occurred and have been reported. We report another unusual feature seen in Activitrax models 8400, 8402, and 8403. This feature consists of continuing in a temporary mode while a different permanent mode was programmed. These eccentricities of the programming features are not very commonly seen, however, they can be somewhat perplexing to the physician following the patient. These unusual features are no longer present in the newer models being manufactured.

Biomedical Engineering↗
PubMed1990

The pig as a model of tachycardia and dilated cardiomyopathy.

Chronic Supraventricular Tachycardia (SVT) can produce a dilated cardiomyopathy which has a poorly understood association with ventricular dysfunction in humans and animals. The purpose of this study was to produce a model of chronic SVT and dilated cardiomyopathy using swine, which have a cardiac anatomy similar to man. Eight pigs were implanted with chronic atrial catheters and a pacemaker, with four additional sham-operated pigs serving as controls. We examined ventricular function and morphology at baseline (120 +/- 3 bpm), pacing baseline (240 bpm), and at 1, 2 and 3 weeks of rapid atrial pacing (240 bpm). Ventricular ejection fractions fell significantly from baseline following 1 week (left: 38 +/- 3% vs baseline 61 +/- 1%; right: 31 +/- 5% vs baseline 56 +/- 1%; p less than 0.05) and deteriorated further by 3 weeks of SVT (left: 26 +/- 4%, right: 19 +/- 3%; p less than 0.05). Significant biventricular chamber dilation developed by 2 weeks of SVT (left: 50 +/- 5 cc vs paced baseline 27 +/- 2 cc; right: 67 +/- 6 cc vs paced baseline 28 +/- 3 cc; p less than 0.05) and continued to increase by week 3 of SVT (left: 66 +/- 11 cc; right: 78 +/- 8 cc; p less than 0.05). Five additional paced pigs, without chronic atrial catheters, were followed using echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The potential utility of sensor-driven pacing in DDD pacemakers.

Sensor-driven pacemakers have clinically improved symptomatology over ventricular pacemakers. Adding rate responsiveness to DDD pacing would theoretically benefit patients with an inability to increase their atrial rate. We evaluated 20 patients who had long-term implanted DDD pacemakers as to the utility of an added effect of rate responsiveness. The pacemakers had been implanted for an average of 34 months. This patient group included 15 patients with atrioventricular (AV) block and five patients with sick sinus syndrome. All patients were exercised on the treadmill until they were fatigued and were monitored to determine their intrinsic heart rate response. A sensor-driven pacemaker was strapped to the patients and was connected to an ECG to measure its rate response. It was set to activity threshold of medium, with a rate response of 7. The 20 patients exercised for an average of 5.9 minutes, with a range of 1.7 to 10 minutes. The maximum intrinsic atrial response averaged 110 beats/min, ranging from 60 to 150 beats/min. The maximum achieved activity rate averaged 99 beats/min, ranging from 60 to 118 beats/min. In 7 of the 20 of patients (35%), the activity pacemaker reached a higher rate than the patient's intrinsic rate. Six had AV block and one had sick sinus syndrome. In these seven patients the peak activity rate response averaged 102 beats/min and their intrinsic activity averaged to 78 beats/min. There was an increase in rate by the addition of rate responsiveness in 35% of our DDD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

A comparison of endoesophageal tubes. Improved results with the Atkinson tube.

We reviewed our use of endoesophageal tubes for the palliation of patients with carcinoma of the esophagus from 1973 through 1986. Celestin tubes were implanted by means of laparotomy and traction. Proctor-Livingston tubes were implanted by pulsion with frequent laparotomy for staging. All Atkinson tubes were placed by means of the pulsion method without simultaneous laparotomy in any case. Patients with an Atkinson tube had fewer complications, including aspiration, sepsis, reflux, and pneumonia. Mean hospital stay was shortened to 4 days when the Atkinson tube was used, and hospital death rate was 6% versus 42% when either the Celestin or Proctor-Livingston tube was used. Mean long-term survival (108 days) was significantly lengthened when Atkinson tubes were used. A comparison of all patients receiving tubes revealed a less frequent prevalence of reflux when the distal end of the tube was positioned above the gastroesophageal junction. Laparotomy resulted in significantly more episodes of aspiration, sepsis, reflux, and pneumonia. Laparotomy was also associated with a 41% hospital death rate versus 17% when laparotomy was not performed. Hospital days were shortened to 7 versus 16 days when laparotomy was not performed. The Atkinson tube provided improved palliation and decreased morbidity and mortality in our hands. These benefits were probably the results of ease of insertion without the use of a laparotomy and the ability in most cases to position the distal end of the tube above the gastroesophageal junction.

Aged↗
PubMed1989

Chemotherapy, radiation therapy, and resection for carcinoma of the esophagus. Long-term results.

From May 1980 to May 1984, preoperative chemotherapy (mitomycin C and 5-fluorouracil) was added to radiation therapy in patients with potentially operable squamous cell carcinoma of the esophagus. Of 129 patients observed, 122 were followed up until death or to the present. Only 33 were able to complete preoperative chemotherapy and radiation and undergo resection. There were 28 men and five women, their ages ranging from 42 to 81 years (average 60 years). There were 22 black and 11 white patients. The location of the tumor was in the middle third in 70% of the patients. Among the 33 patients, the clinical TNM classification was as follows: T1 N0 M0, three patients; T2 N0 M0, 27 patients; T2 N1 M0, two patients; and T3 N0 M0, one patient. The length of the lesions when measurable in the absence of complete obstruction varied from 3 to 17 cm (average 7 cm). The operative mortality rate in this group was 12% (4/33). There was no viable residual tumor in the surgical specimen of the esophagus in 33% (11/33) of those patients completing triple therapy. However, in two of the 11 patients, left gastric nodes contained tumor and in one there was a minute esophageal perforation. The 2-year survival rate was 33% (11/33), and the 5-year survival rate was 15.4% (5/33). Among the 11 patients having 2-year survival, the surgical specimen was normal in six and abnormal in five. Of the five patients having 5-year survival, the surgical specimen was normal in three and abnormal in two. The absence of tumor in the surgical specimen did not appear to confer any better chance for long-term survival. Data were compared to our 1967-1975 series of 75 patients receiving only preoperative radiation and resection. There was no significant difference in survival rates at 2 years (20% [1975] versus 33% [1984], p = 0.2118) or at 5 years (10% [1975] versus 15.4% [1984], p = 0.5796). The addition of preoperative chemotherapy as an adjunct did not result in a statistically significant increase in 2-year or 5-year survival rates.

Adenocarcinoma↗
PubMed1988

Comparison of lead dislodgment and pocket infection rates after pacemaker implantation in the operating room versus the catheterization laboratory.

To assess and compare the rates of lead dislodgment and pocket infection in patients having procedures performed in the operating room versus those performed in the cardiac catheterization laboratory, we reviewed the records of 85 adult patients who underwent 88 procedures, all performed by one surgical team and having complete follow-ups at our institution from October 8, 1979, through November 7, 1986. Forty-five patients underwent 46 procedures in the operating room, and 40 patients underwent 42 procedures in the cardiac catheterization laboratory. There was one instance of ventricular lead dislodgment noted among the 48 leads implanted in the operating room and one instance of ventricular lead dislodgment among the 58 leads implanted in the cardiac catheterization laboratory. No instances of atrial lead dislodgment were noted. No instances of pocket infection were noted among the 46 procedures performed in the operating room or in the 42 procedures performed in the cardiac catheterization laboratory. We conclude that pacemaker implantation can be performed with equivalent safety and effectiveness in the cardiac catheterization laboratory and in the operating room.

Adult↗
PubMed1988

Pacemaker follow-up and adequacy of Medicare guidelines.

The time of occurrence of cardiac pacemaker problems after implantation was identified to assess the adequacy of published federal guidelines for clinic and transtelephonic follow-up. One hundred eighty-nine pacemaker patients' charts were examined retrospectively to identify pacemaker problems: inadequate sensing, non-capture, battery failure, myoinhibition, muscle stimulation, and inadequate threshold safety margin. Twenty-nine patients (15%) were identified as having pacemaker problems. A total of 41 problems were identified, of which 28 (68%) were corrected by reprogramming. Sixty-one percent of the problems were found during a clinic visit. Problems occurred more frequently during the first year in dual-chamber devices (62%) vs single-chamber devices (35%). During years 1 to 4, when few problems are expected, 30% of all problems of single-chamber devices occurred and 39% of all problems of dual-chamber devices occurred. This is a period of time that Medicare guidelines allow for one clinic visit per year for single- and two visits per year for dual-chamber devices. These data suggest: (1) Many pacemaker problems will be missed with transtelephonic follow-up alone. (2) The majority of problems involving dual-chamber devices occurred in the first year. (3) For both dual- and single-chamber devices, an unexpected significant percentage of problems occurred in 1 to 4 years. (4) Medicare guidelines may be inadequate for follow-up during this time period.

Adult↗
PubMed1988

Superior vena cava bypass: use of the azygos vein.

Unexpected involvement of the superior vena cava with dense inflammatory and fibrous tissue was encountered during right pneumonectomy for a T3 N0 M0 squamous cell carcinoma. After expeditiously completing the lung resection, the azygos vein was utilized for a successful superior vena cava bypass.

Azygos Vein↗