High-sensitive Troponin T is not associated with the progression of asymptomatic mild to moderate aortic stenosis: a post hoc substudy of the SEAS trial

Background

Aortic stenosis (AS) and coronary artery disease (CAD) share pathophysiological pathways, as reflected by frequent concomitant revascularization in patients undergoing aortic valve replacement (AVR). High-sensitive Troponin T (hsTnT) is a proven biomarker of cardiomyocyte overload and injury, and predicts postoperative mortality after AVR. However, it is unknown if hsTnT can predict AVR, mortality or ischemic coronary events (ICE) in asymptomatic AS patients.

Purpose

To investigate the hypothesis that increased hsTnT is associated with more severe AS and a higher risk of adverse outcomes in asymptomatic AS patients without overt CAD.

Methods

hsTnT concentrations were examined at baseline and after 1-year follow-up in 1739 asymptomatic AS patients enrolled in the randomized, double-blind Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. The main inclusion criteria were: left ventricular (LV) ejection fraction >55%, transaortic maximal velocity between 2.5–4.0 m/s, and no history of CAD. The primary exposure variable was increased hsTnT (>14 pg/mL according to the assay manufacturer, Roche). This study's primary endpoint was a composite of competing risk outcomes: all-cause mortality as the first event, AVR without revascularization, and ICE (defined as myocardial infarction before AVR, PCI before or combined with AVR, or any CABG). Multivariable regression examined associations between hsTnT and clinical variables. Cox proportional hazards regression models were adjusted for age, sex, creatinine, LV mass index, mean aortic pressure gradient (Pmean) and stratified by center and lipid-lowering treatment. We analyzed outcomes during 5-year follow-up from baseline.

Results

At baseline, 453 (26.0%) patients had increased hsTnT and 302 (17.4%) had moderate-severe AS with a mean (SD) aortic valve area of 0.8 (0.2) cm2 and Pmean of 33.2 (8.8) mmHg. The median annual hsTnT change from baseline to year 1 was 0.8 pg/mL (IQR, −0.4 to 2.3), regardless of AS severity (P=0.08). In adjusted models, log(hsTnT at baseline) was associated with age, sex, creatinine, and LV mass index (all P<0.05), but not with AS severity (P=0.36). The incidence rate ratio for ICE (Figure 1) in patients with increased vs normal baseline hsTnT concentrations was 2.32 (95% CI, 1.72–3.11, P<0.001). In adjusted Cox regression, increased hsTnT was associated with an increased 5-year ICE risk (HR 1.64; 95% CI, 1.18–2.29, P=0.003), but neither with AVR without revascularization nor death (Figure 1).

Conclusion

In these asymptomatic AS patients without overt CAD, hsTnT is often normal and remains stable during 1 year of follow-up regardless of AS severity. Increased hsTnT is associated with CAD-related events, but neither to AS severity nor AVR without concomitant revascularization. This analysis does not support routine hsTnT measurement in asymptomatic AS to predict AVR related to AS progression, although hsTnT could improve the risk assessment for ICE.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Main sponsor (SEAS): Merck & Co Inc, Whitehouse Station, New JerseyBlood analysis sponsor: Roche Diagnostics International Ltd, Switzerland

Biosensing capabilities of bioelectrochemical systems towards sustainable water streams: Technological implications and future prospects

Bioelectrochemical systems (BESs) have been intensively investigated over the last decade owing to its wide-scale environmentally friendly applications, among which wastewater treatment, power generation and environmental monitoring for pollutants are prominent. Different variants of BES such as microbial fuel cell, microbial electrolysis cell, microbial desalination cell, enzymatic fuel cell, microbial solar cell, have been studied. These microbial bioelectrocatalytic systems have clear advantages over the existing analytical techniques for sustainable on-site application in wide environmental conditions with minimum human intervention, making the technology irrevocable and economically feasible. The key challenges to establish this technology are to achieve stable and efficient interaction between the electrode surface and microorganisms, reduction of time for start-up and toxic-shock recovery, sensitivity improvement in real-time conditions, device miniaturization and its long-term economically feasible commercial application. This review article summarizes the recent technical progress regarding bio-electrocatalytic processes and the implementation of BESs as a biosensor for determining various compositional characteristics of water and wastewater.

Individuals with impaired glucose tolerance demonstrate normal cardiac sympathetic innervation using I-123 mIBG scintigraphy

BACKGROUND

Impaired glucose tolerance (IGT) is associated with an increased risk of type 2 diabetes (T2DM) and cardiovascular disease. Some but not all studies have reported cardiac autonomic dysfunction in subjects with IGT and there is only one direct study of cardiac innervation in subjects with IGT. The purpose of this study was to assess global and regional cardiac sympathetic innervation and cardiac autonomic function in individuals with IGT.

METHODS AND RESULTS

We undertook (123)I-mIBG scintigraphy and cardiac autonomic function in 15 subjects with IGT and 15 age and sex-matched healthy controls. Early heart to mediastinum ratio (HMR) (1.71 ± 0.17 vs 1.67 ± 0.13, P = .49), late HMR (1.73 ± 0.18 vs 1.73 ± 0.16, P = .97) and washout rate (WR) (18.6 ± 4.2 vs 19.1 ± 7.6%, P = .84), did not differ between subjects with IGT and control subjects. More detailed regional analysis revealed reduced tracer uptake at the apex, base and inferior wall in all subjects and the anterior wall in a minority of subjects. There were no differences in total score (56.6 ± 4.0 vs 53.3 ± 8.4, P = .193), modified score (48.5 ± 3.3 vs 46.2 ± 6.0, P = .215), anterior wall score (10.2 ± 1.3 vs 10.1 ± 1.6, P = .898), inferior wall score (8.9 ± 1.9 vs 7.7 ± 2.6, P = .163), basal score (18.7 ± 1.9 vs 18.2 ± 3.3, P = .636) and tests of cardiac autonomic function between the groups.

CONCLUSION

Global and regional measures of MIBG uptake and washout as well as cardiac autonomic function did not differ between subjects with IGT and healthy controls.

What is the impact of providing a transcatheter aortic valve implantation service on conventional aortic valve surgical activity: patient risk factors and outcomes in the first 2 years

OBJECTIVES

To assess the impact of introducing a transcatheter aortic valve implantation (TAVI) service on aortic valve surgical activity and outcomes.

DESIGN

A retrospective analysis of prospectively collected data.

SETTING

University hospital of south Manchester.

PATIENTS

815 consecutive patients undergoing isolated aortic valve replacement (AVR) or coronary artery bypass grafting plus AVR from January 2006 to December 2009. Fifty consecutive patients who underwent TAVI from January 2008 to December 2009.

MAIN OUTCOME MEASURES

Aortic valve surgical activity in the 2years before the introduction of a TAVI service and in the 2years following. Outcomes following conventional aortic valve surgery and TAVI.

RESULTS

In the 2years following the introduction of TAVI at this centre, conventional AVR activity has increased by 37% compared with an 8% increase nationally (p<0.001). Compared with the 2years before TAVI there was no change in the mean logistic EuroSCORE (7.4 vs 7.9 p=0.16) or crude mortality rate (2.9% vs 2.1% p=0.48). Fifty high-risk patients underwent TAVI with a 30-day mortality rate of 0%. The mean logistic EuroSCORE of the TAVI patients was 25.3.

CONCLUSIONS

TAVI is an emerging alternative to AVR in high-risk patients. Since the introduction of a TAVI service at this centre, conventional AVR activity has increased. Despite a trend of increasing mean logistic EuroSCORE indicating that more complex cases are being undertaken, there has been a non-significant reduction in the crude mortality rate. Offering a TAVI service has a positive impact on the volume of conventional AVR surgical activity.

Non-adenomatous non-epithelial carcinoma (hemangiopericytoma) of prostate treated with conservative surgery followed by adjuvant chemoradiation

Hemangiopericytoma is a malignant vascular tumour of soft tissue. Microscopically, the tumour shows tightly packed cellular areas surrounding thin-walled branching blood vessels. Traditionally these tumours are treated using wide surgical excision. Only a very few cases of hemangiopericytoma of the prostate have been described worldwide. The feasibility of managing such a case with a combination of conservative surgery and adjuvant anti-malignancy treatment is unexplored. Here, we report a case of hemangiopericytoma of the prostate treated with local excision, with preservation of prostate, followed by adjuvant radiotherapy (40 Gy in 20 fractions to pelvis followed by 24 Gy in 12 fractions as boost to prostate) and chemotherapy (doxorubicin and iphosphamide). Post-treatment computed tomography scan after 4 weeks showed regression of pelvic lymph nodes and a normal-appearing prostate. Levels of serum prostate-specific and carcinogenic embryonic antigen were normal throughout the period of treatment. To date, followup has been uneventful, except for occasional bouts of diarrhea.We conclude that conservative surgery followed by adjuvant radiation and chemotherapy, with subsequent close follow-up, may adequately control localized disease in selected cases of hemangiopericytoma of the prostate. The role of conservative surgery in tumours located at other sites has yet to be defined.

Cardiac involvement in muscular dystrophies

The muscular dystrophies are a heterogeneous group of conditions with a variable distribution and prognosis. Cardiac complications are common and may significantly alter both quality and quantity of life. Whilst complications are disease specific, many patients will require long-term cardiology follow-up looking for the development of a cardiomyopathic process or conduction problems. Improvements in diagnostic techniques now allow mutation-specific diagnosis to be made in some patients so adequate counselling, management and screening can be put in place for individuals and their families.

Left ventricular torsion in primary chronic mitral regurgitation

BACKGROUND

Torsion is essential for normal systolic and diastolic function of the left ventricle (LV), and is known to be abnormal in animal models of mitral regurgitation (MR). There are no comparable data in humans.

OBJECTIVES

To study LV torsion in humans with chronic primary MR using speckle-tracking echocardiography.

METHODS

Rotation and rotation rate were measured from two-dimensional (2D) greyscale LV base and apex short-axis images by speckle-tracking echocardiography in 38 patients and 30 controls. Using custom software, plots of torsion against time were constructed by deducting base rotation from apex rotation. Loops of torsion against LV radial/longitudinal displacement and volume were automatically plotted.

RESULTS

Peak systolic torsion, systolic torsional velocity and untwisting velocity were similar in the two groups. In controls, untwisting started 23 ms before aortic valve closure but was delayed in MR to 15 ms after aortic valve closure, p<0.001. In normal subjects there was rapid untwisting during isovolumic relaxation, with minimal expansion of the LV radial and longitudinal axes. In MR, early untwisting rate was decreased, with less untwisting for a given volume increase. Extensive LV remodelling and worsening MR were associated with progressive reductions in systolic torsion and untwisting velocity, and progressive delay in the onset of untwisting.

CONCLUSIONS

Chronic MR results in significant delay and slowing of LV untwisting, such that early untwisting is coupled with chamber expansion. Correlations between disease severity and torsional parameters suggest a potential role of these variables in assessing early signs of ventricular dysfunction.

Chirality-induced spin-selective properties of self-assembled monolayers of DNA on gold

Here we show that self-assembled monolayers on gold of double-stranded DNA oligomers interact with polarized electrons similarly to a strong and oriented magnetic field. The direction of the field for right-handed DNA is away from the substrate. Moreover, the layer shows very high paramagnetic susceptibility. Interestingly, thiolated single-stranded DNA oligomers on gold do not show this effect. The new findings are rationalized based on recent results in which high paramagnetism was measured for diamagnetic films adsorbed on diamagnetic substrates.

Outcome in the real-world of coronary high-risk intervention with drug-eluting stents (ORCHID)—A single-center study comparing Cypher™ sirolimus-eluting with Taxus™ paclitaxel-eluting stents

OBJECTIVE

We present real world experience from a single center registry comparing the 6-month outcome of percutaneous coronary intervention (PCI) in unselected high-risk individuals using either sirolimus-eluting (SES) or paclitaxel-eluting stents (PES).

METHODS/RESULTS

We compared clinical outcome at 6 months follow-up in two cohorts of 156 consecutive patients (total n = 312) who underwent SES (June 2002-February 2003) and PES (march 2003-July 2003) implantation. The primary endpoint was a composite of major adverse cardiac events (MACE). Baseline clinical characteristics were well matched. The 6-month target vessel revascularization (TVR) rates were 1.9% (SES) and 2.6% (PES) and MACE rates were similar in the two groups (SES 4.5% vs. PES 3.2%, P = NS). In the PES group, intervention for multivessel disease, bifurcation lesions and in small vessels was more common, and for in-stent restenosis less common, reflecting the impact of drug eluting stents on indications for PCI. The incidence of sub-acute stent thrombosis, related to inadequate antiplatelet therapy in 3 of the 6 cases, was 0.95% with no difference between the two groups.

CONCLUSION

This study confirms the safety and efficacy of SES and PES in unselected high risk patients undergoing PCI. Clinical outcomes of both stents are equivalent at 6 months with low rates of MACE and TVR. These data provide important complementary information to forthcoming randomized studies.

Natriuretic peptides in heart valve disease

Synthesis and release of B-type natriuretic peptide (BNP) are increased in heart failure, and plasma concentrations provide important therapeutic and prognostic information. Recent studies have shown that BNP concentrations are also increased with disease of the mitral and aortic valves. The extent of the increase is broadly related to the severity of the valve abnormality and the degree of consequent cardiac remodelling. BNP concentrations appear to relate to prognosis in these patients and might have a role in identifying suitable candidates for cardiac surgery. This paper reviews the current literature and identifies areas where further research is required if assessment of BNP is to be of practical use.

Organization-Induced Charge Redistribution in Self-Assembled Organic Monolayers on Gold

The charge redistribution that occurs within dipolar molecules as they self-assemble into organized organic monolayer films has been studied. The extent of charge transfer is probed by work function measurements, using low-energy photoelectron spectroscopy (LEPS), contact potential difference (CPD), and X-ray photoelectron spectroscopy (XPS), with the latter providing fine details about the internal charge distribution along the molecule. In addition, two-photon photoelectron spectroscopy is applied to investigate the electronic structure of the adsorbed layers. We show that charge transfer acts to reduce the dipole-dipole interaction between the molecules but may either decrease or increase the molecule-to-surface dipole moment.

On the capturing of low-energy electrons by DNA

Many of the mutagenic or lethal effects of ionization radiation can be attributed to damage caused to the DNA by low-energy electrons. To gain insight on the parameters affecting this process, we measured the low-energy electron (<2 eV) transmission yield through self-assembled monolayers of short DNA oligomers. The electrons that are not transmitted are captured by the layer. Hence, the transmission reflects the capturing efficiency of the electrons by the layer. The dependence of the capturing probability on the base sequence was studied, as was the state of the captured electrons. It is found that the capturing probability scales with the number of G bases in the single-stranded oligomers and depends on their clustering level. Using two-photon photoelectron spectroscopy, we find that, once captured, the electrons do not reside on the bases. Rather, the state of the captured electrons is insensitive to the sequence of the oligomer. Double-stranded DNA does not capture electrons as efficiently as single-stranded oligomers; however, once captured, the electrons are bound more strongly than to the single strands.

A method for the morphological analysis of the regurgitant mitral valve using three dimensional echocardiography

BACKGROUND

Atrial en-face reconstructions are commonly used to assess mitral valve morphology in three dimensional (3D) echocardiography but may miss important abnormalities.

OBJECTIVE

To present a systematic method for the analysis of the regurgitant mitral valve using a combination of en-face and longitudinal views for better anatomical evaluation.

METHODS

Detailed 3D assessment was done on 58 patients undergoing mitral valve repair. En-face and longitudinal views were compared for detection and location of primary pathology. The quality of acquisitions under general anaesthesia and sedation was also compared.

RESULTS

Recognition of valve structure was significantly better with longitudinal reconstruction for both mitral leaflets but not for the commissures. Accurate identification of pathology was possible in 95% cases, compared with 50% for en-face reconstruction (p < 0.001). There was no significant difference between imaging under sedation and anaesthesia.

CONCLUSION

En-face reconstructions alone are inadequate. Additional longitudinal reconstructions are necessary to ensure full inspection of valve morphology.

Myocardial viability as a determinant of the ejection fraction response to carvedilol in patients with heart failure (CHRISTMAS trial): randomised controlled trial

BACKGROUND

The improvement in left-ventricular ejection fraction (LVEF) in response to beta blockers is heterogeneous in patients with heart failure due to ischaemic heart disease, possibly indicating variations in the myocardial substrate underlying left-ventricular dysfunction. We investigated whether improvement in LVEF was associated with the volume of hibernating myocardium (viable myocardium with contractile failure).

METHODS

We did a double-blind, randomised trial to compare placebo and carvedilol for 6 months in individuals with stable, chronic heart failure due to ischaemic left-ventricular systolic dysfunction. We enrolled 489 patients, of whom 387 were randomised. Patients were designated hibernators or non-hibernators according to the volume of hibernating myocardium. The primary endpoint was change in LVEF, measured by radionuclide ventriculography, in hibernators versus non-hibernators, on carvedilol compared with placebo. Analysis was by intention to treat.

RESULTS

82 patients dropped out of the study because of adverse events, withdrawal of consent, or failure to complete the investigation. Thus, 305 (79%) were analysed. LVEF was unchanged with placebo (mean change -0.4 [SE 0.9] and -0.4 [0.8] for non-hibernators and hibernators, respectively) but increased with carvedilol (2.5 [0.9] and 3.2 [0.8], respectively; p<0.0001 compared with baseline). Mean placebo-subtracted change in LVEF was 3.2% (95% CI 1.8-4.7; p=0.0001) overall, and 2.9% (0.7-5.1; p=0.011) and 3.6% (1.7-5.4; p=0.0002) in non-hibernators and hibernators, respectively. Effect of hibernator status on response of LVEF to carvedilol was not significant (0.7 [-2.2 to 3.5]; p=0.644). However, patients with more myocardium affected by hibernation or by hibernation and ischaemia had a greater increase in LVEF on carvedilol (p=0.0002 and p=0.009, respectively).

INTERPRETATION

Some of the effect of carvedilol on LVEF might be mediated by improved function of hibernating or ischaemic myocardium, or both. Medical treatment might be an important adjunct or alternative to revascularisation for patients with hibernating myocardium.

Cerebral embolisation during modern cardiopulmonary bypass

OBJECTIVES

Cerebral microembolisation still occurs during cardiopulmonary bypass and may cause both stroke and postoperative cognitive impairment. We investigated the frequency of cerebral embolisation during coronary artery bypass surgery with modern cardiopulmonary bypass and related these to ascending aortic atherosclerosis.

METHODS

Transcranial Doppler monitoring for cerebral embolisation to both middle cerebral arteries was performed in 65 patients undergoing coronary artery surgery with non-pulsatile alpha-stat hypothermic bypass. Epicardial ultrasound imaging of ascending aortic atherosclerosis was performed in 14 patients.

RESULTS

Thirty patients (56.9%) had more than 200 emboli entering the middle cerebral artery territories during surgery; most at the start of bypass and during defibrillation. Readjustment of aortic clamps and aortic cannulation also caused a large number of emboli which were probably particulate. Aortic disease was mild (mean plaque thickness 1 mm, interquartile range 0.9-1.2 mm) and did not relate to the number of cerebral emboli produced by aortic manipulation.

CONCLUSIONS

Cerebral embolisation remains common during coronary surgery despite advances in filter and bypass pump technology. Aortic manipulation and clamping was associated with emboli but epicardial ultrasound imaging was of little help in its prediction.

Validation of an echocardiographic wall motion index in heart failure due to ischaemic heart disease

AIMS

The echocardiographic assessment of left ventricular ejection fraction (LVEF) by geometric methods is limited in many patients because of inadequate views and also in the presence of regional wall motion abnormalities due to ischaemic heart disease (IHD). This study aimed to examine the application of a wall motion index (WMI) method, using a nine-segment LV model in patients with chronic heart failure (CHF) due to IHD.

METHODS AND RESULTS

Echocardiography was performed in 71 consecutive subjects with CHF due to IHD. WMI could be derived in 70 subjects (99%). The inter-observer variability (repeatability coefficient) of WMI was 0.66, i.e. LVEF+/-20%. In 66 subjects, LVEF was measured, within 4 weeks, using radionuclide ventriculography (RNV-EF). The inter-observer variability of RNV-EF was +/-3.1%. Using the mean of two observations for each method, the Bland-Altman range of agreement for LVEF was 26% (+/-13%).

CONCLUSION

WMI is a widely applicable echocardiographic method for assessing LV systolic function and has moderate agreement with RNV-EF. Unlike RNV-EF, however, WMI is not likely to be a suitable method for the measurement of small, but prognostically important, changes in LV function that may occur in CHF.

Restrictive left ventricular filling pattern after myocardial infarction: significance of concomitant preserved systolic function

Restrictive left ventricular (LV) filling identifies a high risk subgroup, following myocardial infarction (MI). The extent and significance of systolic dysfunction in this group is not clear. The aim of our study was to determine the incidence and extent of systolic dysfunction in patients with restrictive filling and nonrestrictive filling examining the prognostic implications. Doppler parameters of LV diastolic function were measured in 102 post-MI subjects within 4 days. Restrictive filling was defined as the presence of E:A ratio > 2 or E:A ratio 1-2 with MDT < or = 140 msec. Follow-up was to a median of 11 months. Restrictive filling (group A) was found in 19 (19%) of 102 patients. Patients with this pattern were more likely to have systolic dysfunction than those without (group B); 63% and 35%, respectively, P = 0.024. Eight (42%) of 19 patients in group A had relatively preserved systolic function. At 11 months 14 patients had developed heart failure (HF), 6 in group A (32%) and 8 in group B (10%), P = 0.012. There were two deaths (11%) in group A and 7 (8%) in group B, P = ns. Seven (88%) of 8 patients in group A with relatively preserved systolic function were alive and free of heart failure at follow-up compared to 4 of 11 patients (36%) in group A with systolic dysfunction (P = 0.026). Restrictive filling can be associated with relatively preserved systolic function after MI and these patients have a relatively good outcome. Patients with restrictive filling post-MI are a heterogeneous group emphasizing the evaluation of both systolic and diastolic function.

Comparison of left ventricular ejection fraction and volumes in heart failure by echocardiography, radionuclide ventriculography and cardiovascular magnetic resonance; are they interchangeable?

AIMS

To prospectively compare the agreement of left ventricular volumes and ejection fraction by M-mode echocardiography (echo), 2D echo, radionuclide ventriculography and cardiovascular magnetic resonance performed in patients with chronic stable heart failure. It is important to know whether the results of each technique are interchangable, and thereby how the results of large studies in heart failure utilizing one technique can be applied using another. Some studies have compared cardiovascular magnetic resonance with echo or radionuclude ventriculography but few contain patients with heart failure and none have compared these techniques with the current fast breath-hold acquisition cardiovascular magnetic resonance.

METHODS AND RESULTS

Fifty two patients with chronic stable heart failure taking part in the CHRISTMAS Study, underwent M-mode echo, 2D echo, radionuclude ventriculography and cardiovascular magnetic resonance within 4 weeks. The scans were analysed independently in blinded fashion by a single investigator at three core laboratories. Of the echocardiograms, 86% had sufficient image quality to obtain left ventricular ejection fraction by M-mode method, but only 69% by 2D Simpson's biplane analysis. All 52 patients tolerated the radionuclude ventriculography and cardiovascular magnetic resonance, and all these scans were analysable. The mean left ventricular ejection fraction by M-mode cube method was 39+/-16% and 29+/-15% by Teichholz M-mode method. The mean left ventricular ejection fraction by 2D echo Simpson's biplane was 31+/-10%, by radionuclude ventriculography was 24+/-9% and by cardiovascular magnetic resonance was 30+/-11. All the mean left ventricular ejection fractions by each technique were significantly different from all other techniques (P<0.001), except for cardiovascular magnetic resonance ejection fraction and 2D echo ejection fraction by Simpson's rule (P=0.23). The Bland-Altman limits of agreement encompassing four standard deviations was widest for both cardiovascular magnetic resonance vs cube M-mode echo and cardiovascular magnetic resonance vs Teichholz M-mode echo at 66% each, and was 58% for radionuclude ventriculography vs cube M-mode echo, 44% for cardiovascular magnetic resonance vs Simpson's 2D echo, 39% for radionuclide ventriculography vs Simpson's 2D echo, and smallest at 31% for cardiovascular magnetic resonance-radionuclide ventriculography. Similarly, the end-diastolic volume and end-systolic volume by 2D echo and cardiovascular magnetic resonance revealed wide limits of agreement (52 ml to 216 ml and 11 ml to 188 ml, respectively).

CONCLUSION

These results suggest that ejection fraction measurements by various techniques are not interchangeable. The conclusions and recommendations of research studies in heart failure should therefore be interpreted in the context of locally available techniques. In addition, there are very wide variances in volumes and ejection fraction between techniques, which are most marked in comparisons using echocardiography. This suggests that cardiovascular magnetic resonance is the preferred technique for volume and ejection fraction estimation in heart failure patients, because of its 3D approach for non-symmetric ventricles and superior image quality.

The carvedilol hibernation reversible ischaemia trial, marker of success (CHRISTMAS) study. Methodology of a randomised, placebo controlled, multicentre study of carvedilol in hibernation and heart failure

BACKGROUND

Carvedilol reduces mortality and improves symptoms and ejection fraction in ischemic heart failure, but its mode of action is not well defined and not all patients respond to treatment. The aim of the CHRISTMAS (Carvedilol Hibernation Reversible Ischaemia Trial, Marker of Success) study is to examine whether hibernation may be a significant factor determining this response. This paper describes the methodology and the rationale for the choice of the nuclear cardiology and echocardiography imaging techniques used in the study.

METHODS AND RESULTS

The CHRISTMAS study is a double-blind, randomised, parallel group, multinational study of oral carvedilol versus placebo in patients with chronic stable heart failure due to left ventricular systolic dysfunction from coronary artery disease. The study aims to randomise 400 patients who are on optimal treatment. Two parallel groups will be randomised to carvedilol or placebo, namely 200 with hibernating myocardium at baseline and 200 matched patients without. The presence of hibernation is defined from a mismatch between regional contractile function and regional viability, measured by echocardiography (severe segmental asynergy) and nitrate prepared resting Tc99m-MIBI myocardial perfusion imaging (segmental activity >60%). The primary treatment-related end-point of the study is the comparison of the mean change, from baseline to the final visit, in radionuclide-determined left ventricular ejection fraction in patients on placebo with those on carvedilol, between the groups designated as hibernating and non-hibernating. Other end-points being examined include the prevalence of hibernation in heart failure, the relationship between the volume of hibernating myocardium and the ejection fraction response, the prevalence of reversible ischemia in heart failure, and the comparison of echo with gated SPECT. To date, 303 patients have been screened and 251 patients randomised in the study. The study aims to report in 2000.

CONCLUSIONS

The CHRISTMAS study addresses the issue of whether the presence of hibernation is a predictor of the ejection fraction response to carvedilol in heart failure. It also examines the potential role of medical therapy in hibernation as well as a number of other end-points. The study may potentially lead to an important new role for nuclear cardiology in heart failure, and demonstrates important synergy between cardiac imaging and the pharmaceutical industry.

Right ventricular involvement in acute myocardial infarction

The presence of right ventricular dysfunction in patients with acute myocardial infarction has important implications. It is a marker for in-hospital mortality and failure to recognize it may lead to inappropriate treatment with serious consequences for the patient. Patients surviving the acute event do, however, have a relatively good long-term prognosis.

Impact of stenting on coronary angioplasty procedures

OBJECTIVE

To compare patient selection and outcome of coronary angioplasty procedures before and after the widespread availability and use of stents.

SUBJECTS AND METHODS

Group 1 consisted of 252 consecutive patients and group 2 comprised 389 patients who underwent angioplasty between April 1993 and March 1994, and April 1995 and March 1996, respectively, in a tertiary cardiothoracic centre. Clinical variables were collected before the procedures. Endpoints included in-hospital death, the need for repeat coronary angiography, repeat angioplasty, and coronary artery bypass surgery. Lesions were classified under American Heart Association/American College of Cardiology criteria in 100 randomly selected patients from each group.

RESULTS

311 and 482 angioplasty procedures were performed in patients from groups 1 and 2, respectively. One or more stents were deployed in nine (4%) and 179 (46%, p < 0.01) patients, respectively. The success rate was higher in group 2 than in group 1 patients (483/523 (92%) v 274/372 (88%), respectively, p < 0.05). There were significantly more single vessel angioplasty procedures (198/252 (79%) v 272/389 (70%), p < 0.05), type A lesions (30/116 (26%) v 19/130 (15%), p < 0.05), patients with stable angina (220/252 (87%) v 311/389 (80%), p < 0.05), and fewer acute myocardial infarction patients (1/252 (0%) v 12/389 (3%), p < 0.05) treated in group 1 than in group 2, respectively. Similar numbers of angioplasty were performed in the left anterior descending, left circumflex, and right coronary arteries. There were no significant differences in the in-hospital mortality or the need for repeat coronary angiography, angioplasty, or bypass surgery at 24 hours or six months after the initial procedure.

CONCLUSION

Patients undergoing angioplasty in the stenting era had features associated with an increased risk of complication. Despite this, the primary success rate was higher, and the complication rate and the need for subsequent revascularisation were similar in the two groups, supporting the widely held clinical impression that stenting has made a valuable impact on the practice of angioplasty.

Trends in pacemaker mode prescription 1984-1994: a single centre study of 3710 patients

OBJECTIVE

To evaluate trends in pacemaker mode prescription from 1984 to 1994 with particular reference to the changes in pacemaker mode prescription for patients aged 80 years and older at implant.

DESIGN

Prospective evaluation of indications for pacing and pacemaker mode prescription in all patients undergoing new pacemaker implantation from 1992 to 1994. Comparison with retrospectively obtained data for patients paced from 1984 to 1991.

SETTING

Tertiary referral cardiothoracic centre.

PATIENTS

Group 1: 2622 patients paced at one centre and entered into the national pacing database from 1984 to 1991. Group 2: 1088 consecutive patients paced from 1992 to 1994.

RESULTS

Use of atrial (AAI) and dual chamber (DDD) pacemakers increased progressively in patients of all ages from 1984 to 1994. There was an increase in the proportion of patients aged 80 years and older from 25.4% (group 1) to 40.5% (group 2). Patients of all ages in group 2 were more likely to receive DDD units for atrioventricular block (odds ratio (95% confidence interval) (CI) 9.0 (7.0 to 11.5)) and AAI or DDD units for sinus node disease (odds ratio (95% CI) 11.0 (7.7 to 15.8)) than those in group 1. Elderly patients (age > or = 80 at implant) with atrioventricular block or sinus node disease and a suitable atrial rhythm were less likely to receive DDD or AAI pacemakers than younger patients in both groups.

CONCLUSIONS

Use of atrial and dual chamber pacing modes has increased substantially in patients of all ages over the last decade. Although elderly patients represent an increasing proportion of the paced population, they remain less likely to receive atrial or dual chamber pacemakers than younger patients.

Early complications of permanent pacemaker implantation: no difference between dual and single chamber systems

OBJECTIVE

To evaluate the incidence of intraoperative and early postoperative complications (up to two months after implant) of endocardial permanent pacemaker insertion in all patients under-going a first implant at a referral centre.

METHODS

Prospective evaluation of all endocardial pacemaker implantation procedures performed from April 1992 to January 1994 carried out by completion of standard audit form at implant. Patients' demographic data, medical history, details of pacemaker hardware used, and any complications were noted. Follow up information was also collected prospectively onto standard forms at pacemaker outpatient clinic.

SETTING

United Kingdom tertiary referral cardiothoracic centre.

PATIENTS

1088 consecutive patients underwent implantation of their first endocardial permanent pacemaker from April 1992 to January 1994. Implant and follow up data were available for 1059 (97.3%) patients at analysis. The median (range) age was 77 years (16-99); 51.2 % were male.

RESULTS

Dual chamber units were implanted in 54.1% of patients, single chamber atrial in 5.2%, and ventricular in 40.7%. A temporary pacing lead was present at implant in 22.9% of patients. Most (93.6%) implants were performed via the subclavian vein. Immediate complications were rare: eight (0.8%) patients developed pneumothorax requiring medical treatment and 11 (1.0%) an insignificant pneumothorax. There was no significant difference in the pneumothorax rate for dual chamber (DDD) compared with single chamber systems. Arterial puncture without sequelae was documented in 2.7% of attempts at subclavian vein cannulation. A total of 35 patients (3.3%) required reoperation; the reoperation rate for dual chamber (3.5%) was similar to that for single chamber (3.1%) systems. Electrode displacement (n = 15, 1.4%) was the most common reason for reoperation. Atrial lead displacement (n = 10, 1.6% of atrial leads) was significantly more common than ventricular lead displacement (n = 5, 0.5% of ventricular leads, P = 0.047). There was no difference in electrode displacement rates for dual (1.6%) compared with single (1.2%) chamber systems. Pacemaker pocket infection led to reoperation in 10 patients (six dual, four single chamber, P = not significant) and was significantly more common in patients who had a temporary pacing lead in place at implant (2.9%) than in those who did not (0.4%, P = 0.0014). Five patients (0.5%) required reoperation for generator erosion (two dual, three single chamber, P = not significant). and a further five for drainage of haematoma or a serous fluid collection (three dual, two single chamber, P = not significant). Complications that did not require reoperation were also rare. Undersensing occurred in 10 patients (0.9%). Atrial undersensing (n = 8) was significantly more common than ventricular undersensing (n = 2, P = 0.017). All patients were successfully treated by reprogramming of sensitivity. Superficial wound infection was treated successfully with antibiotics in nine patients (six dual, three single chamber, P = not significant). Three patients with DDD generators developed sustained atrial fibrillation: two required reprogramming to VVI mode and one required cardioversion.

CONCLUSIONS

Permanent pacing in a large tertiary referral centre with experienced operators carries a low risk. Infection rates are low, < 1% overall but significantly higher in patients who undergo temporary pacing before implantation. Lead displacement and undersensing are more likely to occur with atrial than ventricular leads. The overall complication rate for dual chamber pacing, however, is no higher than for single chamber pacing.

Do radionuclide and echocardiographic techniques give a universal cut off value for left ventricular ejection fraction that can be used to select patients for treatment with ACE inhibitors after myocardial infarction?

OBJECTIVE

To determine whether echocardiography and radionuclide angiography give comparable results when the left ventricular ejection fraction is measured early after myocardial infarction and thus whether, irrespective of the method used, a single value for the ejection fraction could be used as a guide for starting treatment with an angiotensin converting enzyme inhibitor.

DESIGN

Prospective comparison of measurement of left ventricular ejection fraction by echocardiography and radionuclide angiography.

SETTING

Coronary care units of two university teaching hospitals in Glasgow.

PATIENTS

99 patients studied within 36 hours of acute myocardial infarction.

OUTCOME MEASURES

Left ventricular ejection fraction assessed by echocardiography and radionuclide angiography.

RESULTS

70 (77%) of the 99 patients had ejection fraction measured by both echocardiographic and radionuclide techniques, 30 in centre 1 and 40 in centre 2. In centre 1 the mean difference (SD) in ejection fraction (radionuclide angiography--echocardiography) was -8 (10%); 95% CI -12 to -4%. In centre 2 the mean difference was -14 (11%); 95% CI -17 to -11%. If patients had been treated with an ACE inhibitor on the basis of a radionuclide ejection fraction of < 40% then 93% in centre 1 (28 of 30) and 98% in centre 2 (39 of 40) would have been treated. This compares with 63% (19 of 30) and 50% (20 of 40), respectively if echocardiography had been used as a guide.

CONCLUSION

Measurement of ejection fraction is highly dependent on the method used and it is therefore impossible to quote a universally applicable figure for left ventricular ejection fraction below which an ACE inhibitor should be used after myocardial infarction.

Cardiorespiratory and symptomatic variables during maximal and submaximal exercise in men with stable effort angina: a comparison of atenolol and celiprolol

Celiprolol is a novel beta 1 selective adrenoreceptor blocker with partial beta 2 agonism and direct vasodilator activity. These ancillary properties may reduce symptomatic breathlessness and fatigue and modify respiration during exercise. To test this hypothesis 20 men with stable effort angina were enrolled in a double-blind crossover study to investigate the effects of atenolol 100 mg once daily (A) and celiprolol 400 mg once daily (C) on cardiorespiratory and symptomatic variables during maximal and submaximal exercise. Total exercise time on a modified Bruce protocol was similar on both treatments: C12.5 min, A 13.1 min. During steady state submaximal exercise at 60-75% (mean 68%) of maximum work capacity, minute ventilation (C33.81 min-1, A 33.51 min-1), oxygen uptake (C14.6 ml.kg-1.min-1, A15.1 ml.kg-1.min-1), respiratory exchange ratio (C 0.89, A 0.87), ratio of VE/VCO2 (C 33.6, A 33.4), ratio of VE/VO2 (C 2.34, A 2.72), Borg perceived exertion score (C 11.2, A 10.9) and visual analogue scores for breathlessness (C 29.5, A 25.9) and muscle fatigue (C 28.9, A 26.0) were all similar on both treatments. At maximal exercise capacity on the modified Bruce protocol, minute ventilation (C 58.31 min-1, A 60.41 min-1), oxygen uptake (C 21.3 ml.kg-1.min-1, A 21.7 ml.kg-1.min-1), respiratory exchange ratio (C 1.02, A.1.05), ratio VE/VCO2 (C 34.8, A 35.9), and ratio VE/VO2 (C 2.80, A 2.83) were also similar on both drugs. Over a 10 day period anginal attacks (C 10.1 +/- 10.4, A 5.4 +/- 5.9) and sublingual GTN use (C 5.9 +/- 10.3, A 4.4 +/- 9.8) were both more frequent on celiprolol).(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of the DDD pacing mode in patients 80 years of age and older

We reviewed the records of 119 consecutive patients aged 80 years or older (mean age 84 +/- 3.7 years) in whom a dual chamber pacemaker was implanted between 1984 and 1991. Follow-up data was available up to February 1993. Immediate postimplantation complications were rare. Nine patients were lost to follow-up, all within 6 months of implantation. An additional seven patients died within 6 months of implantation. Long-term follow up for at least 6 months from implantation was available for 103 of the 119 patients (87%). Of these 89 (86%) remained in functioning DDD mode for a mean of 22 +/- 15 months from implantation. Nine patients were reprogrammed to VVI mode, six due to atrial fibrillation and three due to failure of atrial sensing or pacing. One patient was programmed DVI for failure of atrial sensing; 94 of 112 patients (84%) whose status was definitely known in February 1993 remained in functioning DDD mode until death or last follow-up. Cumulative survival in DDD mode was 78% at 30 months. We conclude that DDD pacing is stable in the great majority of patients in their ninth and tenth decades who present with rhythms amenable to dual chamber pacing and who have no history of sustained atrial fibrillation.

Relationship of renin, angiotensin II and atrial natriuretic factor to clinical status in the early post-infarct period in patients with left ventricular dysfunction

The vasoconstrictor and cardiotoxic effects of angiotensin II may be particularly harmful in the early post-infarct period, but could be partially offset by the release of atrial natriuretic factor. We studied the relationship of renin, angiotensin II and atrial natriuretic factor to clinical status in the first 72 h after infarction in 36 patients not requiring treatment with diuretics on clinical grounds. Since these patients were treated with streptokinase, 16 non-thrombolysed patients were included to control for the acute effects of streptokinase on plasma hormones. Streptokinase caused transient fluctuations in plasma renin and atrial natriuretic factor but did not limit the subsequent development of supranormal hormone levels. Streptokinase-treated patients were divided on the basis of the highest recorded Killip class. Activation of the renin angiotensin system occurred only in those patients in Killip class 2 (n = 11), was maximal at 24-72 h and was proportional to the extent of left ventricular dysfunction. Plasma levels of atrial natriuretic factor were elevated on admission, even in patients in Killip class 1 (n = 25), but declined within an hour before rising again to supranormal levels at 24-72 h. Cumulative release of renin and angiotensin II, but not atrial natriuretic factor, were significantly greater in patients in Killip class 2. Heart rate was greater in Killip class 2 at 24 and 72 h but there was no difference in mean arterial pressures. We conclude that the renin angiotensin system is activated in the early post-infarction phase, but only in patients in Killip class 2, possibly as a result of increased sympathetic activity and reduced renal perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of internal audit on pacemaker prescription and the immediate costs of pacing in the northern region: towards implementation of the recommendations of the British Pacing and Electrophysiology Group

BACKGROUND

In September 1990 a working party of the British Pacing and Electrophysiology Group recommended the routine use of physiological pacing systems in patients with bradycardia. An audit of the impact of these recommendations on pacemaker prescription in the Freeman Hospital between March 1990 and August 1991 has previously been reported. This paper considers the effect of that internal audit on subsequent pacemaker prescription from September 1991 to February 1993.

PATIENTS AND METHODS

The records of 1228 patients who underwent first pacemaker implantation at the Freeman Hospital between March 1990 and February 1993 were audited retrospectively. The patient's age, indication for pacing, pacing mode, and cost of the generator and leads were recorded. The indications for pacing were sinus node dysfunction (24.9%) (including patients with coexistent sinus node dysfunction and atrioventricular block), atrioventricular block (57.2%), atrioventricular block and atrial fibrillation (12.2%), and carotid sinus syndrome (5.7%). There was an increase in carotid sinus syndrome (2.7% to 8.1%) between the two study periods but no other differences in the distribution of case mix or characteristics of patients. The cost of the working party's recommended optimal pacing mode was calculated from multiplication of the mean cost of the recommended unit over the second half of the study period by the number of patients who would have received that unit.

RESULTS

Between March 1990 and August 1991 atrial pacing for sinus node dysfunction (AAI, AAIR, DDD, or DDDR) increased by 138% (from 25.0% to 59.6%), mainly because of increased use of AAI mode. Physiological pacing for atrioventricular block (DDD or VVIR) increased by 41% (from 17.0% to 24.0%), and VVIR pacing for atrioventricular block with atrial fibrillation increased by 111% (from 10.5% to 22.2%). After the internal audit (that is, between September 1991 and February 1993), physiological pacing for atrioventricular block increased by a further 126% (from 24.0% to 54.2%). Sixty three per cent of this increase was in the first six months after the internal audit. Pacemaker prescriptions in sinus node dysfunction and atrioventricular block with atrial fibrillation were unchanged (59.6% physiological pacing for sinus node dysfunction and 22.2% v 27.3% VVIR pacing for atrioventricular block with atrial fibrillation). These changes in practice were accompanied by an increase in the age of patients receiving physiological units. Costs of pacemaker hardware for the final six months of the audit (excluding carotid sinus syndrome) increased by 38% over the costs that would have accrued had pacing policy remained the same as for the initial six month period before the circulation of the recommendations of the working party. Adoption of the guidelines of the working party in full would lead to a further 66% increase in the costs of hardware.

CONCLUSIONS

The principal effect of the recommendations of the working party alone was increased use of AAI pacing for sinus node dysfunction, with little change in the costs of hardware. The internal audit was followed by an increase in physiological pacing for atrioventricular block, and this has had important financial consequences. Internal audit was followed by closer adherence to the recommendations of the working party.

Neuroendocrine activation and markers of early reperfusion in the acute phase of myocardial infarction

Potentially harmful stimulation of the neuroendocrine axis occurs in the early hours of myocardial infarction. It has been suggested that this acute neuroendocrine response might be attenuated by early therapeutic reperfusion. To test this hypothesis we measured plasma concentrations of atrial natriuretic factor (ANF), renin, adrenaline (ADR) and noradrenaline (NADR) on admission and at 1 h and 4 h in 32 patients undergoing streptokinase treatment within 6 h of myocardial infarction. Fractional changes (FC) in hormone levels were calculated: e.g. ANFO-ANF4/ANFO. Resolution of ST segment elevation at 4 h was the primary measure of reperfusion. Sixteen patients showed ST segment resolution. There was no difference in hormone levels at baseline between reperfused and non-reperfused patients. Fractional changes in ANF, renin and ADR were similar in both groups. NADR fell from admission to 4 h in reperfused patients but rose in non-reperfused (FC 0.28 vs -0.10; P = 0.054). There was no difference in the changes in pulse rate or blood pressure from admission to 4 h between the two groups. Thus there is no evidence that early reperfusion acutely alters the release of ANF, renin or ADR to myocardial infarction. Although plasma NADR tended to fall acutely in reperfused patients this was not accompanied by other markers of sympathetic withdrawal.

Early treatment with captopril after acute myocardial infarction

OBJECTIVES

To determine the effects of early treatment with captopril on haemodynamic function, neuroendocrine biochemistry, left ventricular structure, clinical outcome, and exercise capacity over one year from acute myocardial infarction.

DESIGN

Randomised, double blind, placebo controlled comparison of captopril and placebo.

SETTING

Coronary care units and cardiology departments of two university teaching hospitals in Glasgow.

PATIENTS

99 haemodynamically stable patients with acute myocardial infarction, selected on clinical grounds as being at risk of late ventricular dilatation.

INTERVENTION

Captopril or identical placebo started between six and 24 hours after start of symptoms and continued for 12 months. Target maintenance dose was 25 mg three times a day.

MAIN OUTCOME MEASURES

(a) Acute haemodynamic effects of treatment; (b) neuroendocrine biochemistry from admission to two months; and (c) change in echocardiographic measures of left ventricular size, clinical outcome, and exercise capacity after 12 months of treatment with a separate analysis of the effects of one month of treatment withdrawal on left ventricular volumes.

RESULTS

Captopril caused acute reductions in mean (SEM) pulmonary artery pressure (2.48 (0.69) mm Hg) and systemic vascular resistance (260 (103)) dyn.s.cm-5). Over the first 10 hours captopril reduced mean arterial pressure by 12.1 (2.4) mm Hg compared with 3.8 (1.9) mm Hg in the placebo group. No patient had to be withdrawn from the captopril group because of hypotension. From day 1 onwards systolic and diastolic arterial pressures in the captopril treated group were slightly but not significantly lower than on placebo. There was no difference in the incidence of ventricular or supraventricular arrhythmia with treatment. Captopril prevented the day 3 peak in angiotensin II that occurred in the placebo group (peak concentration (interquartile range): 10.1 (4.8-19.4) pg/ml v 16.8 (4.3-46.3) pg/ml)) but had no effect on atrial natriuretic factor, arginine vasopressin, or catecholamines. Plasma atrial natriuretic factor remained above normal in both groups at two months after infarction. After one year left ventricular volume indices had increased less on captopril than on placebo: left ventricular end systolic volume index 5.4 ml/m2 v 14.7 ml/m2 (95% confidence interval (95% CI) of difference -14.6 to -3.9; p = 0.0011); left ventricular end diastolic volume index 8.4 ml/m2 v 19.0 ml/m2 (95% CI of difference, -17.0 to -4.2; p = 0.0016). Withdrawal of captopril for one month did not affect ventricular volumes. There was no difference in exercise capacity.

CONCLUSIONS

Captopril started between six and 24 hours after acute myocardial infarction is not associated with significant hypotension. It suppresses activation of the renin angiotensin system but has no effect on plasma concentrations of other neurohormones. Atrial natriuretic factor remains raised at two months after myocardial infarction. Captopril significantly decreases left ventricular dilatation. This effect is not lost after one month of treatment withdrawal and is thus due to an alteration of left ventricular structure and not to a short lived haemodynamic action of captopril. Long-term treatment with captopril does not result in improved aerobic exercise capacity after acute myocardial infarction.

Impact of the recommendations of the British Pacing and Electrophysiology Group on pacemaker prescription and on the immediate costs of pacing in the Northern Region

BACKGROUND

The report from the Working Party of the British Pacing and Electrophysiology Group recommends the use of more sophisticated pacemakers in most patients. These proposals were initially circulated in September 1990 and are likely to have major cost implications. Their impact on pacing practice and the immediate costs of pacemaker hardware in the Northern Region were retrospectively audited.

METHODS

The pacing records of 550 patients undergoing a first pacemaker insertion at the Freeman Hospital between March 1990 and August 1991 were reviewed. The patient's age, indication for pacing, pacing mode, and the cost of generator and lead(s) were recorded. The cost was compared with the costs of pacing with the optimal and alternative modes recommended by the Working Party. The costs were calculated from the actual mean cost of the recommended unit over the 18 month period of study multiplied by the number of patients who would have received that unit.

RESULTS

96% of patients were paced for sinus node dysfunction, atrioventricular block, or atrioventricular block and atrial fibrillation. The mean (SD) ages of patients in each diagnostic group were: sinus node dysfunction 69.4 (14), sinus node disease and atrioventricular block 67.2 (17.6), atrioventricular block 73.9 (12.5), atrial fibrillation and atrioventricular block 74.0 (13.9), and carotid sinus hypersensitivity 74.6 (11.6) years. Over the 18 month audit period there was an increase in physiological pacing. AAI pacing in patients with sinus node dysfunction increased by 100% and DDD pacing in atrioventricular block increased by atrioventricular block increased by 56%. Over the whole 18 month period the adoption of the British Pacing and Electrophysiology Groups optimal recommendations would have increased expenditure on pacemaker hardware in the Northern Region by 94% and the use of the alternative mode would have increased it by 61%. For the last six months alone the excess would be 78% and 48%.

CONCLUSIONS

The adoption of the recommendations of the British Pacing and Electrophysiology group in the Northern Region would greatly increase the cost of pacing hardware. The greater part of this increase would be attributable to the routine use of dual chamber pacing in patients with atrioventricular block and the increased use of rate responsive units. The benefits of sophisticated pacing in a predominantly elderly population need to outweigh the disadvantages of the increased cost and complexity of follow up.

Circulating endothelin is not extracted by the pulmonary circulation in man

To determine whether endothelin is extracted from plasma during passage through the pulmonary circulation, we measured its concentration at several points, including the pulmonary artery and the left superior pulmonary vein in seven patients undergoing cardiac surgery. Endothelin concentrations were very similar at all sites sampled. In patients undergoing coronary artery bypass grafting, there is no net pulmonary clearance of endothelin.

Circulating endothelin in acute ischaemic syndromes

BACKGROUND

Endothelin is an extremely potent vasoconstrictor that may have a role in the pathogenesis of acute myocardial ischaemia. Atrial natriuretic factor is an endogenous antagonist of endothelin. To find the pattern and possible importance of circulating endothelin in ischaemic heart disease, concentrations in normal controls and those in patients with stable and unstable angina, acute myocardial infarction, and chronic cardiac failure were compared. The relation between circulating concentrations of endothelin and atrial natriuretic factor in the aftermath of myocardial infarction was also examined.

METHODS

Eighteen patients with acute myocardial infarction, 10 with unstable angina, 10 with stable angina, 12 with chronic cardiac failure, and 10 normal controls were studied. Endothelin concentration was measured in venous plasma by radioimmunoassay. In patients with acute myocardial infarction simultaneous concentrations of endothelin and atrial natriuretic factor were measured on admission and at one, four, and 24 hours.

RESULTS

Mean concentrations (SEM) of endothelin were 5.72 (0.19) fmol/ml in controls, 6.56 (0.48) fmol/ml in stable angina, 6.41 (0.48) fmol/ml in unstable angina, and 13.83 (0.95) fmol/ml in chronic cardiac failure. In acute myocardial infarction concentrations were 8.81 (0.69) fmol/ml on admission, 11.85 (1.02) fmol/ml at one hour, 11.88 (1.10) fmol/ml at four hours, and 7.30 (0.49) fmol/ml at 24 hours. Concentrations of atrial natriuretic factor at the same times were 68.1 (13.1) pg/ml, 8.4 (1.5) pg/ml, 24.4 (4.1) pg/ml, and 42.0 (6.9) pg/ml.

CONCLUSIONS

Plasma endothelin is raised in chronic heart failure and in the aftermath of acute myocardial infarction but not in stable or unstable angina. After myocardial infarction endothelin concentrations are raised whereas concentrations of atrial natriuretic factor are relatively low. The role of endothelin in the pathogenesis of acute myocardial infarction and its interactions with other humoral factors require further investigation.

Plasma endothelin in chronic heart failure

BACKGROUND

Endothelins are recently characterized vasoconstrictor peptides. As chronic heart failure (CHF) is characterized by peripheral arteriolar and renal vasoconstriction, we have measured venous plasma endothelin-like immunoreactivity ("endothelin") in patients with this syndrome.

METHODS AND RESULTS

Compared with age- and sex-matched healthy volunteers (mean +/- SEM plasma endothelin concentration 6.4 +/- 0.3 pmol/l, n = 16), patients with severe CHF had elevated peripheral venous endothelin concentrations (12.4 +/- 0.6 pmol/l, n = 47, p less than 0.01). Plasma endothelin did not increase with exercise in normal subjects or in patients. Plasma endothelin concentration (mean, 13.4 +/- 0.9 pmol/l) did not correlate with plasma atrial natriuretic factor concentration (mean, 88.9 +/- 11.9 pg/ml) in patients with CHF (n = 21). There was also no correlation between plasma endothelin and serum urea or between endothelin and serum creatinine in patients with CHF (n = 34). There was, however, significant renal extraction of endothelin (aorta, 11.1 +/- 0.8 pmol/l; renal vein, 8.8 +/- 0.6 pmol/ml; p = 0.02) in patients with CHF (n = 13).

CONCLUSIONS

Evidence suggests that circulatory endothelin concentrations in the range 5-40 pmol/l are vasoactive. Consequently, the endothelin concentrations found in patients with CHF may be of pathophysiological significance.

Spontaneously acquired fistula from the right coronary artery to the right ventricular cavity

A 47 year old man developed a fistula from the right ventricular branch of the right coronary artery to the right ventricular cavity in association with distal occlusion of the main trunk of the right coronary artery. There was no clinical or electrocardiographic evidence of acute myocardial infarction.

Effects of early captopril administration on infarct expansion, left ventricular remodeling and exercise capacity after acute myocardial infarction

In a double-blind study, 99 patients (82 men, age range 40 to 75 years) with acute myocardial infarction (AMI) were randomly assigned to receive captopril or placebo. Treatment began within 24 hours of admission. Serial echocardiographic measurements of endocardial segment lengths and left ventricular (LV) volumes, and ejection fractions were obtained. The 2 groups were matched at baseline except for an excess of previous AMI in the placebo group (13 of 50 vs 2 of 49 patients, p = 0.002). The increase in anterior segment length, from baseline to 2 months, was significantly less in the captopril than in the placebo group (2.8 +/- 1.6 vs 10.4 +/- 2.4mm, 95% confidence interval [CI] -13.5 to -1.7, p = 0.01). The increase in posterior segment length was also less in the captopril group, but the difference was not significant (3.2 +/- 1.2 vs 7.0 +/- 1.8mm, 95% CI -8.0 to 0.5, p = 0.08). Fewer patients in the captopril group demonstrated increases in segment length greater than 2 standard deviations of the measurement error (14 of 70 [20%] vs 29 of 72 [40%] patients, p = 0.009). In patients with anterior AMI, the infarct-containing anterior segment length increased by 4.5 +/- 2.3 mm in the captopril versus 12.4 +/- 3.1 mm in the placebo group (95% CI -15.7 to -0.2, p = 0.046), and fewer patients in the captopril group demonstrated infarct expansion (6 of 20 [30%] vs 13 of 21 [62%] patients, p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of RAA system and the treatment of patients with ACE inhibition after myocardial infarction

There is activation of the renin angiotensin system after both complicated and uncomplicated myocardial infarction. Angiotensin II increases myocardial oxygen consumption whilst reducing coronary flow and is also directly toxic to the myocardium. Angiotensin converting enzyme inhibitors produce beneficial haemodynamic and neuroendocrine changes in patients with acute left ventricular failure, and may have a role in selected patients with cardiogenic shock. There is evidence to suggest that they might prevent the development of late cardiac failure by limiting the extent of post infarction ventricular dilation. Further research is necessary to define their role in the treatment of acute myocardial infarction.

The effects of angiotensin-converting enzyme inhibition on coronary blood flow and infarct size limitation

A number of theoretical and practical aspects of acute myocardial infarction suggest a potential role for ACE inhibition in enhancing coronary blood flow and limitation of infarct size. Indeed, the use of ACE inhibitors in acute myocardial infarction could be viewed as a logical intervention in the face of the neuroendocrine response which accompanies the acute phase. During the first 24 h post-infarction, very high plasma concentrations of arginine-vasopressin and catecholamines occur. This is followed by a sharp rise in the concentration of angiotensin II (ANG II) over the next few days. The neuroendocrine response is most marked in those patients with larger infarcts, who frequently develop left ventricular failure. The extent to which these factors influence coronary flow in acute myocardial infarction is unknown, although in chronic heart failure ACE inhibition does not reduce coronary blood flow despite a reduction in rate-pressure product, suggesting a coronary vasodilator effect. However, in the presence of fixed coronary stenoses, the fall in blood pressure and, therefore, of coronary perfusion pressure must be taken into account. Whether or not the use of ACE inhibitors can limit infarct size in man also remains to be determined, although it has been clearly demonstrated that concentrations of ANG II similar to those observed in the early phase of myocardial infarction can cause myocardial cell damage in experimental animals. Post-infarction ventricular enlargement can be reduced by ACE inhibitors. Additionally, ACE inhibitors, through their balanced vasodilator effect, maintain cardiac output whilst reducing filling pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Legionella pneumonia complicating Wegener's granulomatosis

We describe a previously healthy man who presented with features consistent with Wegener's granulomatosis. While undergoing investigation, he developed acute respiratory failure, thought to represent progression of his vasculitis. Open lung and sinus biopsies were performed to obtain the diagnosis. Vasculitis was confirmed on the paranasasl biopsy, and the lung biopsy showed pneumonia due to Legionella pneumophila, an association not previously reported in Wegener's granulomatosis. If immunosuppressive therapy had been started without making the diagnosis of Legionella pneumonia on lung biopsy, the patient might well have succumbed to the infection.

Exercise-induced pulmonary hemorrhage in exercising Thoroughbreds: preliminary results with pre-exercise medication

Thoroughbreds with a confirmed history of exercise-induced pulmonary hemorrhage (EIPH) were treated pre-exercise with atropine sulfate, cromolyn, ipratropium or furosemide. Atropine prevented EIPH in 3 of 3 trials in 1 horse, while having no significant effect on bleeding status in the other 2 horses. Pre-exercise treatment with cromolyn had no significant effects in the 3 horses. Pre-exercise treatment of ipratropium was apparently responsible for preventing EIPH in 17 out of 18 trials in 2 horses. The pharmacologic properties of ipratropium in the horse have not been studied, but based on human investigation it seems most probable that its bronchodilator effects are responsible for preventing EIPH in the 2 horses. Furosemide administered in different dosages and time intervals prior to exercise did not prevent EIPH in these 3 horses.