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J L Cox

Publications and source records attributed to J L Cox.

At least 109 records · Page 6Linked to original sources
PubMed1995

Childbirth: life event or start of a long-term difficulty? Further data from the Stoke-on-Trent controlled study of postnatal depression.

BACKGROUND: This paper reports further data from the Stoke study of postnatal depression and examines whether psychosocial characteristics and symptom profiles differ between postnatal and control depression. METHOD: Two hundred and thirty-two postnatal and non-postnatal control women were screened with the Edinburgh Postnatal Depression Scale; all high scorers and a sample of low scores were interviewed with the Standardised Psychiatric Interview and modified Social Maladjustment Schedule. Depression was diagnosed using the Research Diagnostic Criteria. RESULTS: Postnatal but not control depression was associated with a poor relationship with the woman's own mother and greater occupational instability. Depression in control women was associated with low income, having three or more children, performing manual work and occupational dissatisfaction, but postnatal depression was not. There were no differences in the symptom profiles of the postnatal and control women nor between early and late onset postnatal depression. CONCLUSION: Depression is a common and socially disabling disorder affecting mothers of young children. Postnatal depression is more contingent on acute biopsychosocial stresses caused by the arrival of a new family member. Depression in women with older children is more closely related to longer term social adversity.

Adult↗
PubMed1995

Noninvasive testing in women presenting with chest pain: evidence for diagnostic uncertainty.

OBJECTIVE: To gain insight into the diagnostic utility of exercise stress testing in women. DESIGN: Observational prospective cohort study. SETTING: The Victoria General Hospital, Halifax, Nova Scotia. PARTICIPANTS: Consecutive women with chest pain referred by cardiologists or internists for exercise stress testing between May 30, 1992 and November 30, 1992 and followed prospectively to February 28, 1993. INTERVENTION: The proportion of patients subsequently referred for thallium scintigraphy and/or coronary angiography and their clinical profiles were determined. MAIN RESULTS: Of 183 patients studied, stress testing was positive in 48 (26.2%), negative in 48 (26.2%) and nondiagnostic in 87 (47.5%). Women with negative results were more likely to have had normal baseline electrocardiograms (ECGs) (P = 0.002) and least likely to have undergone prior angiography (P = 0.0003). Subsequent thallium scintigraphy and/or coronary angiography was undertaken in 33.3%, 18.8% and 27.6% with positive, negative and nondiagnostic index stress tests, respectively. None of chest pain, cardiac risk factors, previous cardiac investigations or baseline ECG discriminated 33 patients with negative or nondiagnostic stress results who had additional tests from 102 who did not. CONCLUSION: Exercise stress testing poorly screens women with chest pain for coronary artery disease (diagnostic in only 52.5%). Further study was undertaken in 27.6% with nondiagnostic tests and, surprisingly, in 18.8% with negative results. Why certain women with nondiagnostic, and so many with negative, stress tests were referred for further investigation was unclear. These results suggest diagnostic uncertainty when females presenting with chest pain are assessed.

Adult↗
PubMed1995

Revascularization after acute myocardial infarction.

BACKGROUND: The optimal timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (MI) remains controversial. METHODS: We examined our experience retrospectively in 3,942 patients who underwent CABG between 1986 and 1993, including 2,296 patients after acute MI. RESULTS: The operative mortality associated with increasing time intervals between MI and CABG were 9.1%, 8.3%, 5.2%, 6.5%, and 2.9%, for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. In comparison, the operative mortality was 2.5% for patients with no history of acute MI. The incidence of permanent stroke and perioperative MI were greater and the length of postoperative hospitalization was longer for patients undergoing CABG early after MI. For patients undergoing operation electively, however, the operative mortality associated with increasing time intervals between MI and CABG were less, at 0.0%, 3.6%, 2.1%, 6.4%, and 2.1% for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. For patients undergoing CABG within 14 days of MI, the operative mortality was 5.3% for those receiving an intraaortic balloon pump preoperatively for postinfarction angina, but 11.8% for those who underwent urgent/emergent operation without intraaortic balloon pump support. CONCLUSIONS: Elective CABG can be accomplished with acceptable morbidity and mortality early after acute MI if an elective operation is possible. In addition, the intraaortic balloon pump should be used aggressively in patients with postinfarction angina to allow for elective rather than urgent/emergent operation.

Adult↗
PubMed1995

Prognostic significance of increased thallium-201 lung uptake during dipyridamole myocardial scintigraphy: comparison with exercise scintigraphy.

OBJECTIVE: To compare the incidence of cardiac events among patients with increased lung uptake of thallium after dipyridamole stress, matched subjects without such uptake and matched subjects with increased lung uptake during exercise stress. DESIGN: Retrospective case control study based on quantitative and semiquantitative visual consensus analysis of thallium scintigraphy. SETTING: Nuclear cardiology laboratory of a university teaching hospital. PATIENTS: Thirty-six patients with increased lung activity after dipyridamole stress and two groups of matched control subjects identified from 3150 consecutive thallium single photon emission computed tomography studies. INTERVENTIONS: Telephone follow-up and chart reviews to determine the incidence of cardiac events. MAIN RESULTS: Cardiac events were significantly less frequent in the study group with increased lung uptake after dipyridamole stress (two of 36,5%) than in the control group with increased thallium lung uptake at exercise scintigraphy (nine of 36,25%; P = 0.046). CONCLUSIONS: Increased lung uptake of thallium has less ominous short term prognostic significance when observed in association with dipyridamole stress rather than with exercise.

Aged↗
PubMed1995

Prevention of beta-lactam-associated diarrhea by Saccharomyces boulardii compared with placebo.

OBJECTIVES: To determine the safety and efficacy of a new preventive agent for antibiotic-associated diarrhea (AAD) in patients receiving at least one beta-lactam antibiotic. METHODS: A double-blinded, placebo-controlled, parallel group study was performed in a high-risk group of hospitalized patients receiving a new prescription for a beta-lactam antibiotic and having no acute diarrhea on enrollment. Lyophilized Saccharomyces boulardii or placebo (1 g/day) was given within 72 h of the start of the antibiotic(s) and continued until 3 days after the antibiotic was discontinued, after which the patients were followed for 7 wk. RESULTS: Of the 193 eligible patients, significantly fewer, 7/97 (7.2%), patients receiving S. boulardii developed AAD compared with 14/96 (14.6%) on placebo (p = 0.02). The efficacy of S. boulardii for the prevention of AAD was 51%. Using a multivariate model to adjust for two independent risk factors for AAD (age and days of cephalosporin use), the adjusted relative risk was significantly protective for S. boulardii (RR = 0.29, 95% CI = 0.08, 0.98). CONCLUSION: The prophylactic use of S. boulardii given with a beta-lactam antibiotic resulted in a significant reduction of AAD with no serious adverse reactions.

Adult↗
PubMed1995

Electrophysiologic basis, surgical development, and clinical results of the maze procedure for atrial flutter and atrial fibrillation.

After more than a decade of experimental and clinical research into the basic mechanisms underlying atrial fibrillation, we were able to develop a surgical procedure that appears to cure the arrhythmia. This surgical procedure has been used in 100 patients in our institution and in a total of approximately 130 patients by surgeons in other institutions. The surgical results have been excellent, which indicates the sophisticated electrophysiologic mapping systems are unnecessary and that the results are not surgeon-specific.

Animals↗
PubMed1994

Revascularization after acute myocardial infarction: impact of hospital teaching status and on-site invasive facilities.

OBJECTIVE: To investigate the influence of hospital teaching status and service availability on rates of revascularization following myocardial infarction. DESIGN: Retrospective cohort study based on province-wide hospital discharge abstracts. SETTING: All acute care hospitals in Ontario, Canada's most populous province (9.7 million). PATIENTS: Patients admitted to hospital between April 1, 1991, and September 30, 1991, with a principal diagnosis of acute myocardial infarction. MEASUREMENTS: The odds of a patient's having been referred for revascularization (angioplasty or bypass surgery) within six months of a myocardial infarction were calculated based on the type of hospital to which he or she had initially presented, defined as "teaching" or "nonteaching" or as having or not having interventional facilities on-site (cardiac catheterization and/or revascularization). Odds ratios were adjusted for potential confounding variables, and for possible joint effects of teaching status and on-site interventional capabilities. RESULTS: The patients were more likely to have had revascularization (OR 1.79; 95% CI 1.47-2.14, p = 0.0001) when they had been admitted to a teaching hospital, and independently were more likely to have been referred for revascularization (OR 1.34; 95% CI 1.09-1.66, p = 0.0067) when they had been admitted to a hospital with on-site interventional facilities. There was no interaction between teaching status and service availability regarding referral for revascularization. CONCLUSION: Teaching status is an important determinant of revascularization following acute myocardial infarction and is independent of service availability, which also influences revascularization rates.

Adult↗
PubMed1994

Human ventricular tachycardia: precise intraoperative localization with potential distribution mapping.

Electrophysiologically guided operations for ventricular tachycardia (VT) have been directed exclusively by activation time maps. Even with computer-assisted mapping, extensive editing is required, which prolongs the duration of the operation and which may introduce significant error. In contrast, potential distribution maps can be constructed in less than 3 minutes and can be viewed as a movie of developing and receding potentials. In 4 patients undergoing operation for VT, endocardial mapping was performed using form-fitting electrodes containing 160 points. A computerized mapping system, capable of simultaneously recording 256 channels of data, was used to analyze data and to display potential distribution maps sequentially at 1-millisecond intervals as a color movie. A total of eight morphologies of sustained VT were mapped. The mean VT cycle length was 340 +/- 40 milliseconds (range, 274 to 394 milliseconds). In 3 patients with ischemic heart disease, four VT morphologies originated from the subendocardium. All were successfully ablated with cryoablation alone or in conjunction with aneurysmectomy and endocardial resection. A fourth patient with VT secondary to cardiomyopathy had multiple morphologies and received an implantable cardioverter defibrillator. Potential distribution maps correlated well with the concomitant activation time maps. Thus, potential distribution mapping provides a rapid and accurate means of identifying the site of origin of VT facilitating intraoperative mapping in patients undergoing surgical ablation.

Action Potentials↗
PubMed1994

Potential ablation of accessory atrioventricular pathways: injection of alcohol into the atrioventricular groove.

Accessory atrioventricular (AV) pathways responsible for the Wolff-Parkinson-White syndrome have been treated successfully by surgical and radiofrequency catheter ablation techniques. In this study, we explored the feasibility of permanent chemical ablation of accessory pathways by direct injection of 100% ethanol into the canine AV groove. Right coronary artery blood flow and AV compartment pressure were measured in 5 adult mongrel dogs (part I) during injection of saline solution (10 to 15 mL) into the right AV groove. Atrioventricular groove compartment pressure increased from 1 +/- 1 to 31 +/- 12 mm Hg (p < 0.0001) and right coronary artery blood flow increased slightly from 117 +/- 17 to 138 +/- 44 mL/min (p = not significant). In 8 additional dogs (part II), 100% ethanol (10 mL) was injected into the left AV groove. After 6 weeks (n = 6) or 12 weeks (n = 2), histologic examination of the left AV groove demonstrated localized fibrous replacement of injured epicardial muscle, with only scant inflammatory infiltrate. Mild intimal fibrosis and intimal proliferation were present in the circumflex artery and its larger branches, but no significant luminal narrowing was evident. Angiograms at 12 weeks (n = 2) demonstrated no significant narrowing of the circumflex artery. In summary, injection of 100% ethanol into the AV groove is capable of locally ablating myocardial tissue, presumably including conductive tissues, while sparing the coronary arteries.

Animals↗
PubMed1994

From fisherman to fibrillation: an unbroken line of progress.

The modern era of cardiac arrhythmia surgery was initiated by Dr Will C. Sealy in May 1968, when he performed the first successful surgical division of an accessory pathway for the treatment of the Wolff-Parkinson-White syndrome. During the subsequent 25 years, arrhythmia operations evolved through a series of innovative surgical procedures capable of curing essentially all refractory clinical arrhythmias. The lessons learned during the development of these surgical procedures ultimately led to the refinement and eventual success of less invasive catheter techniques that have now replaced most of these surgical techniques. The surgical experience gained during these years also made possible the current surgical procedure that is used to treat the most complex, and the most common, of all cardiac arrhythmias, atrial fibrillation. Few areas of any specialty are as clearly defined as the unbroken line of progress that extends from Dr Sealy's first procedure in 1968 to the successful surgical treatment of atrial fibrillation in 1994.

Adult↗
PubMed1994

Direct operation versus ICD therapy for ischemic ventricular tachycardia.

Now that the implantable cardioverter defibrillator is available as a therapeutic option for the management of ventricular tachycardia (VT), some argue that there no longer should be a role for direct surgical intervention for this malignant arrhythmia. Rebuttal of this argument is difficult for the following reasons: (1) there are many patients who are candidates for implantable cardioverter defibrillator therapy but not for direct VT operation, and thus direct comparisons of the two therapies is difficult; (2) implantable cardioverter defibrillator therapy by definition is palliative, but a VT operation is curative in most instances; (3) in many electrophysiologic triage algorithms, implantation of a cardioverter defibrillator and VT operation are employed as alternative, not competitive, therapies, again making direct comparisons difficult; and (4) probably most importantly, there are misconceptions in the literature regarding the risks and benefits of direct VT surgical procedures as they are currently performed. In this brief review, we examine the currently available data on both sides of this argument.

Catheter Ablation↗
PubMed1994

On-site prothrombin time, activated partial thromboplastin time, and platelet count. A comparison between whole blood and laboratory assays with coagulation factor analysis in patients presenting for cardiac surgery.

BACKGROUND: Although available hemostasis assays from institutional laboratories permit an analytical approach to diagnosis and treatment of coagulation disorders following cardiopulmonary bypass, their clinical utility has been limited by delays in obtaining results. The development of instrumentation for on-site testing allows rapid return of results. This study was designed to compare whole blood (WB) results obtained from on-site coagulation assays with values provided by our institutional laboratory (LAB). METHODS: After Institutional Human Studies Committee approval, 362 patients presenting for cardiac surgery requiring cardiopulmonary bypass were enrolled in this study. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet count (PLT) assays were performed in both WB and LAB systems. PT, aPTT, and PLT measurements were compared between WB and LAB assays using blood specimens obtained from at least two time points for each patient. Normal range values for both PT and aPTT methods were determined by using measurements from a normal reference population. Coagulation factor levels were measured in a subset of patients to characterize the response of PT and aPTT assays to individual and multiple factor levels. To employ Bayes' theorem and calculate predictive indexes (e.g., sensitivity, specificity), the disease or factor deficiency was determined using factor levels. Predictive indexes were used to evaluate the ability of PT and aPTT assays to identify factor deficiency. RESULTS: PLT counts were similar between systems. Linear regression and bias analysis demonstrated similar results for WB and LAB PT and discordant results for aPTT measurements. Both PT assays had a similar normal range, whereas a wider distribution of results was evident for the WB aPTT normal range. Although statistically greater slopes for factor:aPTT regressions were observed for the WB system, WB aPTT correlated better with factor V and with factor V, VIII, and XII levels (multivariate linear regression). Diagnostic performance for factor levels less than 0.3 and 0.4 U/ml was similar for both WB and laboratory PT and aPTT assays. WB and LAB PT and aPTT assays performed similarly in detecting factor deficiency in the period after cardiopulmonary bypass. CONCLUSIONS: WB PT and PLT values correlate well with those obtained from the LAB. The discrepancy between measurement systems in aPTT values is probably a reflection of both different normal ranges and responsiveness to factor deficiency. These WB assays provide coagulation results that can accurately identify patients with quantitative deficiencies in platelets and coagulation factors.

Adult↗
PubMed1994

Anterior septal coronary artery infarction in the canine: a model of ventricular tachycardia with a subendocardial origin. Ablation and activation sequence mapping.

BACKGROUND: In humans, chronic ventricular tachycardia (VT) is usually associated with myocardial infarcts that involve the interventricular septum. In an effort to more closely mimic the anatomic substrate that gives rise to chronic VT in humans, we developed a canine model of VT in which the anterior septal coronary artery was ligated. The site of earliest activation, the subsequent activation sequence, and the mechanism of VT associated with the resultant ventricular septal infarct was then evaluated to determine if this model accurately reflected the characteristics of human VT. METHODS AND RESULTS: Seventeen dogs underwent occlusion-reperfusion ventricular septal infarcts. Four to 7 days later, electrophysiological studies were performed. VT was initiated by programmed electrical stimulation and terminated by pacing at a cycle length of 50% to 75% of the VT cycle length. Electrophysiological studies were performed using a 256-channel mapping system. A total of 15 VT morphologies were mapped in 9 animals. Fourteen of 15 morphologies had septal subendocardial sites of earliest activation and 1 had a septal midwall site of earliest activation. VT ablation was performed using a nitrous oxide cryoprobe and confirmed the site of earliest activation by subsequently rendering VT noninducible. Electrophysiological studies demonstrated four distinct VT activation sequences: (1) circular reentrant (n = 7), (2) concentric spread (n = 5), (3) figure-of-eight (n = 2), and (4) septal midwall (n = 1). CONCLUSIONS: This canine model of ventricular septal infarction produces VTs with sites of earliest activation and activation sequences similar to those in humans. A reentrant mechanism as the basis of these arrhythmias is supported by the following observations: (1) all VT was initiated and terminated with programmed electrical stimulation; (2) VT activation sequences were consistent with reentry; and (3) precise interruption of the sequence terminated the VT and rendered it noninducible.

Animals↗