The effect of salinity on the phase behaviour of total lipid extracts and binary mixtures of the major phospholipids isolated from a moderately halophilic eubacterium.

The effects of molar NaCl concentrations on the phase behaviour of the total lipid extracts and binary mixtures of the major phospholipids, namely phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), isolated from the moderately halophilic eubacterium, Vibrio costicola, grown in 1 M and 3 M NaCl containing media have been studied using X-ray diffraction and freeze-fracture electron microscopy. The effect of both the PE/PG ratio and alterations in fatty acid composition were examined by using binary mixtures which mimicked the PE/PG ratio found in the native bacterial membranes. We show that the samples exhibited complex phase behaviour, including the formation of non-bilayer phases, which depend upon the salinity of both the bacterial culture medium and the suspending solution. The total lipid from bacteria cultured in 1 M NaCl-containing medium and dispersed in 1 M NaCl exhibited a mixture of L alpha and hexagonal-II phases at the optimum growth temperature of the organism (i.e., 30 degrees C), whereas the same lipid dispersed in 3 M NaCl showed only a hexagonal-II phase down to a temperature of +3 degrees C. The total lipid extracted from 3 M NaCl cultures showed only lamellar phases over the temperature range studied (+50 degrees C to -50 degrees C), but the phase transition temperatures of the various lamellar phases were generally higher when the lipid was dispersed in 3 M compared with 1 M NaCl. The phase behaviour of the binary mixtures was similar but not identical to that of the corresponding total lipid extracts and it is suggested that the minor lipid components (diphosphatidylglycerol, lysophosphatidylethanolamine and lysophosphatidylglycerol) play a part in determining the phase behaviour of the native membranes. These results show that the PE/PG ratio and fatty acid composition of the individual phospholipids, which are normally regulated by Vibrio costicola in vivo in response to culture medium salinity, are both important in maintaining a stable bilayer structure within the membrane.

Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly.

OBJECTIVES: We sought to identify the pattern of disturbed left ventricular physiology associated with symptom development in elderly patients with effort-induced breathlessness. BACKGROUND: Limitation of exercise tolerance by dyspnea is common in the elderly and has been ascribed to diastolic dysfunction when left ventricular cavity size and systolic function appear normal. METHODS: Dobutamine stress echocardiography was used in 30 patients (mean [+/-SD] age 70 +/- 12 years; 21 women, 9 men) with exertional dyspnea and negative exercise test results, and the values were compared with those in 15 control subjects. RESULTS: Before stress, left ventricular end-diastolic and end-systolic dimensions were reduced, fractional shortening was increased, and the basal septum was thickened (2.3 +/- 0.5 vs. 1.4 +/- 0.2 cm, p < 0.001, vs. control subjects) in the patients, but posterior wall thickness did not differ from that in control subjects. Left ventricular outflow tract diameter, measured as systolic mitral leaflet septal distance, was significantly reduced (13 +/- 4.5 vs. 18 +/- 2 mm, p < 0.001). Isovolumetric relaxation time was prolonged, and peak left ventricular minor axis lengthening rate was reduced (8.1 +/- 3.5 vs. 10.4 +/- 2.6 cm/s, p < 0.05), suggesting diastolic dysfunction. Transmitral velocities and the E/A ratio did not differ significantly. At peak stress, heart rate increased from 66 +/- 8 to 115 +/- 20 beats/min in the control subjects, but blood pressure did not change. Transmitral A wave velocity increased, but the E/A ratio did not change. Left ventricular outflow tract velocity increased from 0.8 +/- 0.1 to 2.0 +/- 0.2 m/s, and mitral leaflet septal distance decreased from 18 +/- 2 to 14 +/- 3 mm, p < 0.001. In the patients, heart rate rose from 80 +/- 12 to 132 +/- 26 beats/min and systolic blood pressure from 143 +/- 22 to 170 +/- 14 mm Hg (p < 0.001 for each), but left ventricular dimensions did not change. Peak left ventricular outflow tract velocity increased from 1.5 +/- 0.5 m/s (at rest) to 4.2 +/- 1.2 m/s; mitral leaflet septal distance fell from 13 +/- 4.5 to 2.2 +/- 1.9 mm (p < 0.001); and systolic anterior motion of mitral valve appeared in 24 patients (80%) but in none of the control subjects (p < 0.001). Measurements of diastolic function did not change. All patients developed dyspnea at peak stress, but none developed a new wall motion abnormality or mitral regurgitation. CONCLUSIONS: Although our patients fulfilled the criteria for "diastolic heart failure," diastolic dysfunction was not aggravated by pharmacologic stress. Instead, high velocities appeared in the left ventricular outflow tract and were associated with basal septal hypertrophy and systolic anterior motion of the mitral valve. Their appearance correlated closely with the development of symptoms, suggesting a potential causative link.

A comparison of hemodynamic effects of one-month oral captopril and enoximone treatment for severe congestive heart failure.

A double-blind, randomized, crossover trial was undertaken to compare the effect of enoximone (150 mg, 3 times daily) and captopril (25 mg, 3 times daily) added to conventional therapy with diuretics in the treatment of 13 patients with severe chronic heart failure. Each treatment was continued for 1 month. Heart failure was due to idiopathic dilated cardiomyopathy in 6 patients and coronary artery disease in 7. Hemodynamic measurements were made at rest and during exercise, on entry to the study and after each treatment period. The cardiac index at rest was 1.9 +/- 0.2 liters min-1 m2 (mean +/- 1 standard deviation) and did not change with either drug. Systemic vascular resistance at rest decreased with enoximone (p less than 0.05) and was unchanged with captopril. Systemic vascular resistance at peak exercise was not lowered by either drug. Both drugs caused an increase of cardiac index at peak exercise (p less than 0.04) and a prolongation of exercise time (p less than 0.05). No difference was detected between the hemodynamic response to the 2 drugs after 1 month treatment either at rest or during exercise.

Complete heart block and severe tricuspid regurgitation after radiotherapy. Case report and review of the literature.

Cardiac complications can occur long after chest radiotherapy. We describe a patient who developed both valve disease and complete heart block at different intervals following radiotherapy for Hodgkin's disease. The combined presentation of these two very rare cardiac complications and surgery for radiation-induced tricuspid valve disease have not been described before.

A Rapid Access Heart Failure Clinic provides a prompt diagnosis and appropriate management of new heart failure presenting in the community.

BACKGROUND AND AIMS: The diagnosis of heart failure is an important clinical problem and yet reported diagnostic accuracy in primary care is less than 50%. We established a Rapid Access Heart Failure Clinic (RAHFC) in a district general hospital serving a population of 292,000 in SE London, UK, to diagnose and manage new cases of heart failure presenting for the first time in the community. METHODS: Patients with suspected new onset heart failure were referred by their Primary Care Physician without appointment for clinical assessment on the same or next working day. Assessment by a specialist registrar in cardiology included history, examination, chest X-ray, electrocardiogram (ECG) and echocardiogram. When a diagnosis of heart failure was made appropriate treatment, including angiotensin converting enzyme inhibitors (ACEI), was started. RESULTS: Over 15 months 383 patients were seen (0.4 cases/100,000 population/weekday) 178/383 (46%) were considered to have definite or possible heart failure at the initial assessment in the RAHFC. A normal ECG (negative predictive value 94%) and chest X-ray virtually excluded the diagnosis of heart failure. After subsequent specialist investigations and follow-up, including a trial of therapy where appropriate, 101/383 (26%) were finally diagnosed as clinical heart failure. ACEI therapy was commenced in 56/57 (98%) of patients in whom it was considered appropriate. CONCLUSION: The RAHFC provided rapid assessment, prompt diagnosis and early introduction of life prolonging therapy for patients presenting with suspected heart failure in the community.

Abnormal ventricular activation and repolarisation during dobutamine stress echocardiography in coronary artery disease.

OBJECTIVE: To assess possible ECG changes caused by dobutamine stress and their relation to wall motion disturbances in patients with coronary artery disease. DESIGN: Prospective recording and analysis of 12 lead ECG at rest and during each stage of dobutamine stress echocardiography, and correlation with wall motion changes. SETTING: A tertiary referral centre for cardiac disease equipped with non-invasive facilities for pharmacological stress tests. SUBJECTS: 27 patients, mean (SD) age 60 (8) years, with documented evidence of coronary artery disease in whom dobutamine stress echo was clinically indicated, and 17 controls of similar age. RESULTS: In controls, all ECG intervals shortened with increasing heart rate but in the patient group only PR and QT intervals shortened while QRS duration broadened and QTc interval prolonged progressively. In the 27 patients, 16 developed chest pain, 15 with reduced left ventricular long axis systolic excursion (p < 0.001), and all showed reduced peak lengthening rate; ST segment shift appeared in 16, 13 of whom developed chest pain, but did not correlate with reduction of either systolic long axis excursion or peak lengthening rate; QRS duration broadened in 20, 16 with reduction of long axis excursion (p < 0.02) which was more often seen at the septum (p < 0.005); QTc interval prolonged in 19, all of whom had associated reduction of peak long axis lengthening rate (p < 0.02). CONCLUSIONS: QRS duration and QTc interval both normally shorten with dobutamine stress, while in coronary artery disease they both lengthen: changes in QRS duration correlate with systolic and QTc interval with diastolic left ventricular wall motion disturbances. ST segment shift also occurred in most patients, but without consistent correlation with wall motion abnormalities. It was thus less discriminating than the other two abnormalities in this respect.

Early continuous ST segment monitoring in unstable angina: prognostic value additional to the clinical characteristics and the admission electrocardiogram.

BACKGROUND AND OBJECTIVE: In unstable angina, clinical characteristics, resting electrocardiography, and early continuous ST segment monitoring have been individually reported to identify subgroups at increased risk of adverse outcome. It is not known, however, whether continuous ST monitoring provides additional prognostic information in such a setting. DESIGN: Observational study of 212 patients with unstable angina without evidence of acute myocardial infarction admitted to district general hospitals, who had participated in a randomised study comparing heparin and aspirin treatment versus aspirin alone. METHODS: Clinical variables and a 12 lead electrocardiogram (ECG) were recorded at admission, and treatment was standardised to include aspirin, atenolol, diltiazem, and intravenous glyceryl trinitrate, in addition to intravenous heparin (randomised treatment). Continuous ST segment monitoring was performed for 48 h and all inhospital adverse events were recorded. RESULTS: The admission ECG was normal in 61 patients (29%), showed ST depression in 59 (28%) (17 > or = 0.1 mV), and T wave changes in a further 69 (33%). The remaining 23 had Q waves (18), right bundle branch block (four), or ST elevation (one). During 8963 h of continuous ST segment monitoring (mean 42.3 h/patient), 132 episodes of transient myocardial ischaemia (104 silent) were recorded in 32 patients (15%). Forty patients (19%) had an adverse event (cardiac deaths (n = 3), non-fatal myocardial infarction (n = 6) and, emergency revascularisation (n = 31)). Both admission ECG ST depression (P = 0.02), and transient ischaemia (P < 0.001) predicted an increased risk of non-fatal myocardial infarction or death, while no patients with a normal ECG died or had a myocardial infarction. Adverse outcome was predicted by admission ECG ST depression (regardless of severity) (odds ratio (OR) 3.41) (P < 0.001), and maintenance beta blocker treatment (OR 2.95) (P < 0.01). A normal ECG predicted a favourable outcome (OR 0.38) (P = 0.04), while T wave or other ECG changes were not predictive of outcome. Transient ischaemia was the strongest predictor of adverse prognosis (OR 4.61) (P < 0.001), retaining independent predictive value in multivariate analysis (OR 2.94) (P = 0.03), as did maintenance beta blocker treatment (OR 2.85) (P = 0.01) and admission ECG ST depression, which showed a trend towards independent predictive value (OR 2.11) (P = 0.076). CONCLUSIONS: Patients with unstable angina and a normal admission ECG have a good prognosis, while ST segment depression predicts an adverse outcome. Transient myocardial ischaemia detected by continuous ST segment monitoring in such patients receiving optimal medical treatment provides prognostic information additional to that gleaned from the clinical characteristics or the admission ECG.

Cancer screening coverage of south Asian women in Wakefield.

OBJECTIVE: To measure the cervical and breast screening coverage of south Asian women in Wakefield, compared with other city residents. DESIGN: Pairwise measurement of screening histories of women whose names appeared to be south Asian, and of non-Asian women matched by date of birth and general practice. DATA SOURCE: Computerised records of screening histories held by West Yorkshire Central Services Agency, for the eight general practices in central Wakefield. RESULTS: 67% of south Asians and 75% of non-Asians had acceptable (not overdue) cervical screening histories (chi(2)=13.75, p<0.001). 53% of south Asians and 78% of non-Asians had acceptable breast screening histories (chi(2)=8.5, p<0.01) CONCLUSION: Interventions should be designed to improve coverage for breast screening among south Asian women. The need for such interventions for cervical screening is equivocal.

Atenolol or nicardipine alone is as efficacious in stable angina as their combination: a double blind randomised trial.

BACKGROUND: Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone. METHODS: This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period. RESULTS: Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination. CONCLUSIONS: Nicardipine and atenolol are equally effective in prolonging exercise duration and time to onset of ischemia in patients with chronic stable angina while the combination appeared to offer no additional benefit. Nicardipine prolonged the time to onset of angina significantly; again there was no further improvement with the combination. Neither drug appears to have an important effect on the parameters of diastolic function studied in patients with chronic stable angina.

Left ventricular volume in thrombolysed patients with acute anterior myocardial infarction: the effect of captopril and xamoterol.

We measured left ventricular volume in 70 asymptomatic patients after first Q-wave anterior myocardial infarction in order to determine whether ventricular dilatation occurs and whether there is evidence for its attenuation or prevention by treatment with captopril or xamoterol--PRevention Of VEntricular Dilatation?: the PROVED? study. 77% of patients received thrombolytic treatment. Patients were randomised a mean of 11 days after infarction to receive either captopril 25 mg three times daily, xamoterol 200 mg twice daily or matching placebo. After 6 months of treatment, 6 patients from the placebo group (n = 24), 1 from the captopril group (n = 23) and 3 from the xamoterol group (n = 23) had been withdrawn from the study because of clinical complications. Left ventricular volume was measured using magnetic resonance imaging, before randomisation and after 6 months of treatment. Changes in left ventricular end-diastolic and end-systolic volume after 6 months of treatment were defined prospectively as the primary endpoints. Mean initial end-diastolic volume index was 85 (S.D. 19) ml/m2, mean end-systolic volume index was 45 (S.D. 18) ml/m2, and mean ejection fraction was 48 (S.D. 11)% for the whole group. There was no significant change in left ventricular volume index in the placebo or either treatment group after 6 months of treatment. Only minimal left ventricular dilatation was evident at 11 days. No further increase in left ventricular volume occurred after six months and there was no additional benefit from treatment with either captopril or xamoterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of heart failure in three general practices in north west London.

There is little recent information on the prevalence of heart failure in the United Kingdom. Assuming that patients with heart failure would be taking diuretic drugs all such patients were identified in three general practices in north west London. The practice records of these patients were examined to determine which patients had heart failure. Of the 30,204 patients served by the practices, 117 had heart failure, a prevalence of 3.9 per 1000 patients. The mean age of these patients was 74 years. The prevalence of heart failure among patients under 65 years of age was 0.6 per 1000 patients rising to 27.7 per 1000 among those aged 65 years and over. The aetiology of heart failure was considered to be coronary heart disease for 32% of patients, valve disease for 19%, hypertension for 6%, cor pulmonale for 4% and congenital heart disease for 2%. The aetiology for the remaining 37% of patients was unknown. Most patients were referred to hospital and only 20% had been treated solely by the general practitioner. An electrocardiogram and chest radiograph had been obtained for over 80% of patients but only 28% had an echocardiogram. Heart failure occurs primarily in elderly patients, and coronary heart disease is the dominant aetiological factor.

Comparison of methods to assess coronary heart disease prevalence in South Asians.

BACKGROUND: Migrants from the Indian subcontinent (South Asian migrants) in the United Kingdom have high mortality from coronary heart disease (CHD) in comparison to the indigenous population. Few studies have assessed the prevalence of CHD in South Asians, and the applicability of conventional survey methods in this population is not known. In this pilot random population survey of South Asian men and women living in West London, the prevalence of CHD as judged by the Rose questionnaire, past cardiac history, cardiologist and resting electrocardiogram were compared. METHODS: Subjects aged 30-64 years from randomly selected households were invited for a cardiological assessment. A lay person administered the Rose questionnaire and recorded the past cardiac history. A cardiologist also made an independent assessment and a 12-lead electrocardiogram was recorded and analysed according to the Minnesota code. RESULTS: Three hundred and seventy-six individuals (192 men and 184 women) were assessed. The prevalence of angina in men and women, respectively, was 3.1% and 4.9% by the Rose questionnaire; 2.6% and 2.2% by past cardiac history; and 4.2% and 0.5% according to the cardiologist. The prevalence of myocardial infarction in men and women, respectively, was 5.2% and 2.2% by the Rose questionnaire, 3.6% and zero by past cardiac history and 3.6% and 0.5% by the cardiologist. Q/QS codes were present in 1.6% men and 0.5% women and ischaemic codes in 13% men and 14% women. Ischaemic changes were not associated with any cardiac history in 72% of men and 92% of women. For a diagnosis of CHD in men, there was poor agreement between the Rose questionnaire and either the past cardiac history or the cardiologist's assessment, but moderate agreement between the past cardiac history and the cardiologist. Agreement was poor between all three methods for a positive diagnosis of CHD in women. CONCLUSION: Current accepted epidemiological methods for assessing CHD prevalence may be inaccurate in South Asians, especially women. Electrocardiogram abnormalities suggestive of ischaemia are common in South Asians and are usually not associated with evidence of CHD. Thus, their value as indicators of CHD is questionable.

Newly diagnosed heart failure: change in quality of life, mood, and illness beliefs in the first 6 months after diagnosis.

OBJECTIVES: This study sought to examine how patients' mood and quality of life (QoL) change during the early high-risk period after a diagnosis of heart failure (HF) and to identify factors that may influence change. DESIGN: A within-subjects, repeated-measures design was used. Assessments took place within 4 weeks of diagnosis and 6 months later. METHODS: One hundred and sixty six patients with HF completed assessments of their mood, QoL, and beliefs about HF and its treatment. Correlation analysis was conducted between the variables and analysis of variance and t-tests were used to assess differences in categorical variables. To examine which variables predicted mood and QoL, hierarchical multiple regressions were conducted. RESULTS: At follow-up, patients' beliefs indicated a realization of the chronicity of their HF, however their beliefs about the consequences of having HF did not change and their satisfaction with their treatment remained high. QoL and anxiety improved significantly over time but there was no significant change in depressed mood. As would be expected, improvement in symptoms was a key factor in improved mood and QoL. Other significant explanatory variables included age, comorbid chronic obstructive pulmonary disease, depressed mood, patients' beliefs about the consequences of their HF and their concerns about treatment. CONCLUSIONS: This study suggests that addressing patients' mood and beliefs about their illness and its treatment may be additional ways of improving patient QoL in the early period after the diagnosis of HF.