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Biomedical subjects

J Lindsay

Publications and source records attributed to J Lindsay.

At least 91 records · Page 5Linked to original sources
PubMed1993

Diagnostic accuracy of seismocardiography compared with electrocardiography for the anatomic and physiologic diagnosis of coronary artery disease during exercise testing.

A multicenter study was performed to compare the diagnostic accuracy of a new technique, seismocardiography, with that of electrocardiography for physiologically and anatomically significant ischemic coronary artery disease (CAD) during exercise stress testing. Five participating centers enrolled 129 patients who had simultaneous seismocardiograms and 12-lead electrocardiograms at the time of their exercise treadmill stress tests. Two different definitions of CAD were used: anatomic and physiologically significant disease. The presence of anatomically significant CAD (> or = 50% diameter stenosis) was documented by coronary angiography. Physiologically significant CAD was defined as present in the same 129 patients when coronary arteriography (> or = 50% diameter stenosis) and thallium-201 scintigraphy (defect on initial postexercise images) were both abnormal. Seismocardiography had a significantly better sensitivity for detecting anatomic CAD than did electrocardiography (73 vs 48%; p < 0.001), without loss of specificity (78 vs 80%; p = NS). Exercise seismocardiography added significant incremental diagnostic information beyond that provided by exercise electrocardiography. Seismocardiography was more sensitive (without less specificity) in women and in patients who did not achieve maximal predicted heart rate. In patients with physiologically significant CAD, the seismocardiogram was also significantly more sensitive (78%) than was the electrocardiogram (55%) (p < 0.02), without loss of specificity (84 vs 74%). Seismocardiography significantly improved sensitivity for the detection of anatomic and physiologic CAD. It is easy to perform and may be a clinically useful adjunct in exercise stress testing.

Coronary Angiography↗
PubMed1993

Late outcome and quality of life following percutaneous transluminal coronary angioplasty in octogenarians.

Limited data are available concerning the long-term survival and quality of life of octogenarians treated with percutaneous transluminal coronary angioplasty (PTCA). We retrospectively compared the results of PTCA in 118 octogenarians to that of 500 younger subjects. Among the octogenarians, long term follow-up was obtained including survival, relief of angina, assessment of quality of life, and capacity for independent living. These results were compared between men and women. The clinical success rate was 93% for the octogenarians and 88% for the younger patients (p = NS). The lesion success rates were 89% and 88% for these groups, respectively. Results of multilesion PTCA and dilatation of coronary occlusions were similar in both age groups. Major complication rates were 5.9% for the elderly and 3.8% for the younger patients (p < .008). Hospital mortality was higher among the octogenarians (4.6% vs 0.2%, p < .05). Among long-term octogenarian survivors, > 90% indicated a high level of satisfaction with their quality of life and health status. If needed, 88% would undergo the procedure again. Independent living was possible for 66% of these patients and automobile driving for 55%. Octogenarian men and women had similar baseline clinical characteristics, procedural success, complications, relief of angina, and survival. Women indicated a slightly lower level of satisfaction and capacity for independent living. PTCA can achieve a success rate in octogenarians comparable to that of younger patients but with an increased risk of serious complications. Patient satisfaction remains high and a majority of octogenarians remain physically active and capable of independent living.

Activities of Daily Living↗
PubMed1993

Aortocameral fistula: a rare complication of aortic dissection.

The false channel of an aortic dissection only rarely ruptures into a cardiac chamber producing an aorto-cameral fistula. Reports of 20 cases have been published, and two distinct clinical patterns have emerged. In nine patients, severe cardiac decompensation associated with chest pain developed abruptly months to years after coronary bypass graft surgery or aortic valve replacement. Continuous murmurs were observed infrequently. In 11 patients, progressive chronic or subacute congestive heart failure developed in patients with aortic dissection known or suspected to have occurred months to years previously. A continuous murmur was almost always present. The frequency with which aortocameral fistula occurred in patients who had undergone cardiac surgery suggests a pathogenetic mechanism. It seems probable that postoperative adhesions favor fistula over free rupture.

Aortic Dissection↗
PubMed1992

Methicillin-resistant Staphylococcus aureus colonization in a long-term-care facility.

OBJECTIVE: To study the prevalence and risk factors for colonization with MRSA at a long-term-care facility. DESIGN: Cross-sectional surveillance culture survey. SETTING: A 233-bed university-affiliated long-term-care facility. MEASUREMENTS: Surveillance cultures for MRSA were performed on patients of two adjacent nursing units and on new admissions to the entire facility over a 4-month period. RESULTS: On the chronic medical unit, where patients known to be colonized had been cohorted, 20 of 38 (52.6%) were colonized vs 3 of 67 (4.5%) on the skilled/intermediate unit (P less than 0.001), suggesting that little intra-facility spread of MRSA occurs. Twenty-four of 55 (43.6%) chronic medical admissions were colonized vs 6 of 63 (9.5%) admitted to the other units (P less than 0.001). Thirteen of 30 (43.3%) admissions were not previously known to be colonized. By univariate analysis, colonized admissions were younger and more often male; had more listed diagnoses, including pressure sores, a previous positive MRSA culture, and urinary incontinence; were more often fed by feeding tube; and had longer durations of hospital stay prior to admission. Logistic regression analysis showed that the most powerful independent predictors of colonization at admission were: a prior positive culture for MRSA (OR 8.8, 95% CI 2.4, 32.4), male sex (OR 8.2, 95% CI 2.3, 29.7), urinary incontinence (OR 3.8, 95% CI 1.4, 10.4), and presence of pressure sores (OR 2.9, 95% CI 0.9, 9.2). CONCLUSIONS: Unrecognized colonization of nursing home residents with MRSA is common, and nursing homes are unwittingly repositories for patients colonized with MRSA following acute hospitalization. Gloving and careful attention to handwashing may limit spread of MRSA within nursing homes, and identification of colonized patients may be facilitated by targeted surveillance cultures of the most debilitated patients at admission.

Aged↗
PubMed1991

Ventricular late potentials in myotonic dystrophy.

OBJECTIVE: To determine the prevalence of ventricular late potentials, as determined by signal-averaged electrocardiography, in patients with myotonic dystrophy. DESIGN: Cross sectional, with blinded analysis of all electrocardiographic data. SETTING: Outpatient departments of a Veterans Affairs medical center and a tertiary care private hospital. PARTICIPANTS: Twenty-four patients with myotonic dystrophy. Patients were excluded from the study if they had either a history suggestive of significant ventricular arrhythmias or electrocardiographic evidence of a bundle-branch block. Two comparison groups were also formed; one group included 44 healthy employees at the tertiary hospital and the other, 30 cardiac patients with inducible ventricular tachycardia. MAIN RESULTS: A time-domain analysis of the signal-averaged electrocardiograms showed that 75% of patients with myotonic dystrophy met one criterion for the presence of late potentials, 67% met two criteria, and 29% met all three criteria. Spectrotemporal mapping in these patients showed markedly abnormal spectral peaks with a mean factor of normality that was significantly lower than that of the normal volunteers; the frequency of electrocardiographic abnormalities approached that seen in patients with known ventricular tachycardia. The presence of late potentials correlated directly with the length of the PR interval and inversely with left ventricular fractional shortening. CONCLUSIONS: In our study, the prevalence of late potentials on signal-averaged electrocardiography in patients with myotonic dystrophy approached that seen in cardiac patients with inducible ventricular tachycardia. It is possible that ventricular arrhythmias play a role in the occurrence of sudden death in some patients with myotonic dystrophy.

Adult↗
PubMed1991

A comparison of multilesion percutaneous transluminal coronary angioplasty in elderly patients (greater than 70 years) and younger subjects.

Results of multilesion percutaneous transluminal coronary angioplasty (PTCA) were compared in 210 elderly patients (70 to 92 years, [group I] and 210 younger patients (40 to 69 years, [group II]. The elderly patients included more women (43% versus 24%) and patients with unstable angina (73% versus 55%). PTCA was successful in 87% of lesions in group I and in 94% in group II (p less than 0.001). Only circumflex artery dilatation was less successful in group I (78% versus 91%, p less than 0.002). PTCA was successful in all lesions of at least one vessel in 89% of group I patients and in 94% of group II patients (p less than 0.06). Successful dilatation of all lesions was achieved in 77% of group I and in 85% of group II patients (p less than 0.05). Complication rates were similar for both groups. These data demonstrate a high rate of success and safety in elderly patients undergoing multilesion PTCA despite the presence of several risk factors (advanced age, female sex, unstable angina). The lower PTCA success rate in these patients compared with younger subjects is almost entirely attributable to reduced success for circumflex artery lesions.

Age Factors↗
PubMed1990

Probe angioplasty of total coronary occlusion using the Probing Catheter technique.

Coronary angioplasty (PTCA) of total coronary occlusion is limited by the inability of guidewires and conventional dilating catheters to cross all such lesions. A new technique was therefore prospectively evaluated for PTCA of these lesions using the ultra-low-profile Probe "balloon on a wire" device. An intracoronary Probing Catheter was used to facilitate crossing the stenosis with a guidewire and then to deliver a Probe into the obstruction for balloon dilatation. This technique was utilized in 64 consecutive patients with "absolute" coronary occlusions demonstrating no angiographically detectable antegrade coronary flow. Successful dilatation was achieved in 47 (73%). Among 33 occlusions of less than 3 mo duration 31 (94%) were successfully dilated whereas only 16 of 31 more chronic occlusions were dilated (P less than .01). Chronic occlusions with a tapered morphology and those located more than 1 cm from a branch point were more frequently dilatable. There were no serious complications including no vessel perforations with this technique. The Probing Catheter technique offers a safe and effective method for the dilatation of recent coronary occlusions by using balloon on a wire technology.

Angioplasty, Balloon, Coronary↗
PubMed1990

Use of continuous ambulatory peritoneal dialysis in a nursing home: patient characteristics, technique success, and survival predictors.

Forty-four end-stage renal disease (ESRD) patients admitted to a nursing home were treated with continuous ambulatory peritoneal dialysis (CAPD). The technical feasibility of using CAPD in this setting was demonstrated by an acceptable peritonitis rate (1.3 episodes per patient-year), acute hospitalization rate (18.5 days per patient-year), and only two technique failures. However, 6-month and 12-month survival rates were 53% and 29%, respectively. Survival analysis using the Cox model showed that patients with better functional status on admission measured by activity of daily living scores and who had previously been in an outpatient dialysis program before admission survived longer and were more often discharged.

Activities of Daily Living↗
PubMed1989

Probabilistic division systems modeling the generation of mosaic fields.

The explanation of mosaic pattern in chimeric organs analyzed by in situ methods requires modeling of specific hypotheses. The use of computer simulations to achieve this has led to the conclusion that finely variegated mixtures of cell lineage within chimeric tissues does not require extensive cell movement. Cell division models were used to determine the distribution of patch size as mosaic fields are generated. The results establish that these distributions are sensitive to the proportion of the two cell types which comprise the mosaic.

Animals↗