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Biomedical subjects

N Curzen

Publications and source records attributed to N Curzen.

26 records · Page 2Linked to original sources
PubMed1996

Women with chest pain: is exercise testing worthwhile?

OBJECTIVE: To determine the diagnostic value of the exercise tolerance test (ETT) in women presenting with chest pain. DESIGN: Prospective study of all women presenting to a centre with chest pain between 1987 and 1993 who were assessed by an ETT and coronary angiography. SETTING: The outpatient clinic of one consultant cardiologist in a tertiary referral centre. PATIENTS: All women referred to this outpatient clinic with chest pain were screened. For inclusion, patients had to perform ETT and undergo coronary angiography. Of the 347 referred during this period, 142 were excluded because they were unable to perform ETT or because of Q waves or other abnormalities on their resting electrocardiogram. RESULTS: Overall the sensitivity of the ETT was 68% and the specificity was 61%, with a positive predictive value of 0.61 and a negative predictive value of 0.68. There were 42 false positive and 31 false negative ETT results (36% of the study group). The predictive value of a negative test was higher in younger women (< 52 years) than in the older group (> or = 52 years) (P = 0.004), but the positive predictive value in the two groups was not significantly different. The predictive value of a negative test was also higher in those with two or fewer risk factors than in those with three or more risk factors (P = 0.001). The negative predictive value for those women above 52 years with three or more risk factors (24% of the study group) was only 0.25. Lack of chest pain during ETT was associated with a higher negative predictive value in the younger group than in the older women (P = 0.006). CONCLUSIONS: In women with chest pain use of the ETT was a misleading predictor of the presence or absence of coronary disease in 36% of these patients. In particular, a negative test in older women with three or more risk factors had a very low predictive value. The inclusion of risk factors and division by age can, however, be used to identify a population at intermediate risk for coronary artery disease in whom the ETT result has the highest diagnostic utility.

Adult↗
PubMed1995

Detection of ambulatory ischaemia is not of practical clinical value in the routine management of patients with stable angina. A long-term follow-up study.

It has been reported that medically treated patients with stable angina and positive exercise test for ischaemia have an adverse 1-2 year outlook if they are shown also to have transient, and predominantly silent, ischaemic episodes detected by ambulatory ST segment monitoring during their daily activities: it has been suggested that this investigation could be used to identify patients more likely to benefit from early investigation and treatment. We assessed the long-term (up to 65 months) prognostic significance of transient ischaemic episodes during daily activities in 172 patients routinely attending cardiac outpatients with medically treated stable angina who had undergone exercise testing and 48 h of ambulatory ST segment monitoring between February 1988 and August 1989 for this purpose. A positive exercise test for ischaemia was not a prerequisite for inclusion. One hundred and four patients (60.5%) had a positive exercise test for ischaemia and 72 (42%) had transient ischaemia during daily activities (63 had both tests positive). Over a median 50-month follow-up period 54 patients suffered at least one cardiac event (primary event: cardiac death n = 7; non-fatal myocardial infarction n = 11; unstable angina n = 18; elective CABG/PTCA n = 18). Two further patients suffered non-cardiac death. Cardiac events, either objective (cardiac death or non-fatal myocardial infarction) or subjective (unstable angina or revascularisation) were no more likely to occur in those with transient ischaemia during daily life when compared with those without, at follow-up times up to 65 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Value of physical signs in the diagnosis of ventricular tachycardia.

BACKGROUND: Although the use of physical signs for the diagnosis of ventricular tachycardia (VT) was described in the early 1900s, their value in this role has never been systematically assessed. METHODS AND RESULTS: Using a blinded, randomized protocol, we examined the ability of 26 clinicians to detect ventriculoatrial (VA) dissociation during cardiac pacing in 21 patients with both atrial and ventricular pacing wires in situ after successful ablation of accessory pathways. In protocol 1 (10 patients), pacing was randomized to either ventricular pacing alone (simulating VT) or to atrioventricular sequential pacing (simulating supraventricular tachycardia or VT with intact VA conduction) at rates of 150 or 180 beats per minute. Each patients was examined by four clinicians blinded to the pacing mode. Clinicians were asked to make a diagnosis of "VA association" or "VA dissociation" after examining the patient for variability of the arterial pulse, jugular venous pulse (JVP), and first heart sound. In protocol 2 (11 patients), randomization of pacing mode was performed between examination of each of the three physical signs so that the value of each sign was assessed individually. In protocol 1, a diagnosis of VA dissociation (VT) was made in 21 of 40 observations, with a specificity of 75%, sensitivity of 70%, and a positive predictive value (PPV) of 71%. In protocol 2, from a total of 132 observations (44 for each sign), the sensitivity, specificity, and PPV for a diagnosis of VT were as follows: arterial pulse, 61%, 71%, 70%; JVP, 96%, 75%, 82%; and first heart sound, 58%, 100%, 100%. CONCLUSIONS: It is concluded that, in patients with a regular tachycardia of uncertain origin, clinically detectable variations in the first heart sound and JVP are highly specific and sensitive indicators, respectively, of a diagnosis of VT. Assessment of the arterial pulse is of little value in this role.

Adult↗
PubMed1993

Prognostic significance of transient ST segment changes after coronary artery bypass surgery: a long-term (4-10 year) follow up study.

OBJECTIVE: To assess the long-term (four to 10 years) prognostic significance of transient ST segment changes on ambulatory ST segment monitoring after coronary artery bypass grafting (CABG). PATIENTS AND METHODS: 76 patients (67 men, nine women) underwent CABG between 1982 and 1984 (n = 31) and between 1987 and 1988 (n = 45) and at a mean age of 57. All underwent 48 hours of ambulatory ST segment monitoring at a mean of 19 weeks after surgery. The results were available for assessment. All general practitioners were contacted and patients' notes reviewed. Patients were contacted by telephone. Details were recorded of intervening events (acute myocardial infarction, unstable angina, need for further revascularisation, and deaths). Event free survival curves were produced for those with and without transient ST segment changes during routine postoperative ambulatory ST segment monitoring. RESULTS: During 3213 hours of monitoring after CABG, 21 (27.6%) of 76 patients had transient ST segment changes, of which 70% were silent. Over a mean 70 month follow up period, patients with such ischaemic changes were no more likely to have either an objective (myocardial infarction or cardiac death) or subjective (unstable angina or another revascularisation) event than those patients without ischaemic changes. This finding was the same in patients operated on between 1987 and 1988 and between 1982 and 1984. CONCLUSIONS: Although ambulatory ST segment monitoring is becoming increasingly popular in some countries as a routine investigation for ischaemia in various coronary subgroups, the findings of such an investigation, when performed after CABG, do not help to identify a subgroup more likely to have an adverse outcome during up to 10 years of follow up. There seems to be no reason to perform this investigation after surgery, and particularly to refer patients for reinvestigation because of the detection of predominantly silent ST segment changes of uncertain relevance.

Adult↗
PubMed1993

Obstructive sleep apnoea associated with syringomyelia.

We present a case of obstructive sleep apnoea in association with syringomyelia. We describe the successful treatment of the respiratory obstruction by continuous positive airway pressure and then by surgical means. This rare combination of conditions and the management is reviewed.

Adult↗
PubMed1987

Effects of a cyclo-oxygenase inhibitor, flurbiprofen, and an H1 histamine receptor antagonist, terfenadine, alone and in combination on allergen induced immediate bronchoconstriction in man.

The effect of flurbiprofen, a potent cyclo-oxygenase inhibitor, on histamine and methacholine reactivity was assessed in seven atopic subjects with asthma. Flurbiprofen 150 mg daily for three days displaced the histamine-FEV1 concentration-response curve to the right by 1.5 doubling doses, whereas no effect was observed on the response to methacholine. Subsequently the effects of flurbiprofen and terfenadine, a specific H1 histamine receptor antagonist, on allergen induced bronchoconstriction were studied in seven atopic but non-asthmatic subjects. The subjects inhaled the concentration of grass pollen allergen that had previously been shown to produce a 20% fall in FEV1 on separate occasions after prior treatment with placebo, flurbiprofen 150 mg daily for three days, terfenadine 180 mg three hours before challenge, and the combination of flurbiprofen and terfenadine. After placebo, allergen challenge caused a mean (SEM) maximum fall in FEV1 of 37.6% (2.6%) after 20 (3.7) minutes, followed by a gradual recovery to within 15% of baseline at 60 minutes. Terfenadine reduced the maximum allergen provoked fall in FEV1 to 21.5% (2.2%) and reduced the area under the time-response curve (AUC) by 50% (6%). Flurbiprofen alone reduced the mean maximum fall in FEV1 to 29.6% (3.2%) and reduced the AUC by 26%. The effect of the combination of flurbiprofen and terfenadine did not differ significantly from that of terfenadine alone. We conclude that histamine and prostaglandins contribute to immediate allergen induced bronchoconstriction and that a complex interaction occurs between the two classes of mediators.

Adult↗