Seven-day holter monitoring detects more significant arrhythmias than 24-hour and 3-day monitoring

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

24-hour Holter monitors have been used widely to assess patients with suspected and known arrhythmias. Recent studies have shown increased yield of arrhythmia detection with longer durations of Holter monitoring.

Purpose

The aim of the study was to evaluate the incremental yield in significant arrhythmias detected using a 7-day continuous Holter monitor, as compared to what can be achieved within a 24-hour and 48 to 72 hours study.

Methods

A retrospective study of patients from 72 sites in two geographical locations, A and B, who completed a continuous 7-days patch monitor study was performed. 801 of these studies detected significant arrhythmias; pauses 3 seconds or more (PA), ventricular tachycardia of 6 beats or more (VT), and paroxysmal atrial fibrillation (PAF). The day of the first occurrence of a significant arrhythmia was noted and tallied to determine the incremental yield of a multiday Holter monitoring.

Results

Of 801 total cases detected with significant arrhythmia, only 278 (35%) were detected in the first 24hours, while 523 (65%) cases were detected after Day 1. 331 (41%) had first significant arrhythmia detected after the 3rd day of monitoring, with 68 (44%) being PA, 125 (40%) PAF, and 138 (41%) VT. Notably, in Group A, 31 (72%) of total VT detected and 35 (72%) of total PAF detected were first picked up after Day 1, 21 (49%) of total VT were first detected only after the 3rd day of monitoring.

Conclusions

1-day (24-hour) monitoring period fails to detect a significant number of potentially serious cardiac arrhythmias. Extended continuous Holter monitoring increases the yield of detection, with a substantial fraction (40-49%) detected after the 3rd day of monitoring. No difference in results obtained between two geographical locations demonstrates strong evidence that findings are consistent across different sites. Review of current practice and guidelines is necessary to further expand usage of multiday Holter monitoring, thus increasing benefits to patients.

Updated S2 K guidelines for the management of bullous pemphigoid initiated by the European Academy of Dermatology and Venereology (EADV)

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease of the skin and mucous membranes. This disease typically affects the elderly and presents with itch and localized or, most frequently, generalized bullous lesions. A subset of patients only develops excoriations, prurigo-like lesions, and eczematous and/or urticarial erythematous lesions. The disease, which is significantly associated with neurological disorders, has high morbidity and severely impacts the quality of life.

OBJECTIVES AND METHODOLOGY

The Autoimmune blistering diseases Task Force of the European Academy of Dermatology and Venereology sought to update the guidelines for the management of BP based on new clinical information, and new evidence on diagnostic tools and interventions. The recommendations are either evidence-based or rely on expert opinion. The degree of consent among all task force members was included.

RESULTS

Treatment depends on the severity of BP and patients' comorbidities. High-potency topical corticosteroids are recommended as the mainstay of treatment whenever possible. Oral prednisone at a dose of 0.5 mg/kg/day is a recommended alternative. In case of contraindications or resistance to corticosteroids, immunosuppressive therapies, such as methotrexate, azathioprine, mycophenolate mofetil or mycophenolate acid, may be recommended. The use of doxycycline and dapsone is controversial. They may be recommended, in particular, in patients with contraindications to oral corticosteroids. B-cell-depleting therapy and intravenous immunoglobulins may be considered in treatment-resistant cases. Omalizumab and dupilumab have recently shown promising results. The final version of the guideline was consented to by several patient organizations.

CONCLUSIONS

The guidelines for the management of BP were updated. They summarize evidence- and expert-based recommendations useful in clinical practice.

Detection sensitivity of laser feedback interferometry using a terahertz quantum cascade laser

We report on the high detection sensitivity of a laser feedback interferometry scheme based on a terahertz frequency quantum cascade laser (QCL). We show that variations on the laser voltage induced by optical feedback to the laser can be resolved with the reinjection of powers as low as ∼-125  dB of the emitted power. Our measurements demonstrate a noise equivalent power of ∼1.4  pW/√Hz, although, after accounting for the reinjection losses, we estimate that this corresponds to only ∼1  fW/√Hz being coupled to the QCL active region.

Vitamin D levels in 87 Asian patients with cutaneous lupus erythematosus: a case-control study

BACKGROUND

Cutaneous lupus erythematosus (CLE) is an autoimmune disease, often exacerbated by sun exposure. Patients are encouraged to avoid sun exposure, therefore predisposing them to vitamin D deficiency.

AIM

To investigate the prevalence of and risk factors for vitamin D deficiency in patients with CLE.

METHODS

Total serum 25-hydroxy vitamin D (25(OH)D) was measured in 87 consecutive patients with CLE and in 79 controls. Clinical characteristics, disease severity, medications used and lifestyle factors were analysed and compared to determine risk factors for inadequate (25(OH)D), defined as a serum (25(OH)D) level of < 20 μg/L.

RESULTS

We found that 51% (n = 44) of the patients with CLE had 25(OH)D levels of < 20 μg/L compared with 73% (n = 58) of the controls (P < 0.01). No significant differences in (25(OH)D) levels were found between cases and controls with regard to age, sex, ethnicity, smoking, sun exposure, sunblock use or vitamin D supplementation. Treatment with antimalarials showed a statistically significant association with lower vitamin D levels.

CONCLUSION

Low levels of vitamin D were found in both patients with CLE and controls. Despite being on vitamin D supplementation and living in an equatorial location, our Asian patients with CLE still had low levels of vitamin D. It is therefore important to ensure adequate vitamin D supplementation in patients with CLE, especially for those who are on antimalarial therapy.

Increased risk of strontium ranelate-related SJS/TEN is associated with HLA

Severe adverse drug reactions (ADR) of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) in some patients receiving strontium ranelate have been reported, but the risk factors are unclear. We show that HLA-A*33:03 and B*58:01 are significantly associated with patients who developed SJS/TEN; and provide the first evidence that genetic risk factors are involved in strontium ranelate-associated SJS/TEN.

INTRODUCTION

In this study, HLA as a genetic risk factor was assessed among osteoporotic patients prescribed with strontium ranelate that developed severe cutaneous adverse drug reactions (SCARs) compared with those who were tolerant.

METHODS

Genomic DNA isolated from peripheral blood mononuclear cells (PBMCs) of patients was HLA typed using sequencing-based typing method to determine their HLA profiles.

RESULTS

Osteoporotic patients who are currently on strontium ranelate were enrolled in the study (n = 76). Tolerant controls were defined as patients who received strontium ranelate for a minimum of 3 months (range 3 months to 8 years) with no reports of any cutaneous reactions as these reactions usually occur within the first 12 weeks after starting treatment. Retrospective cases of SJS/TEN were also identified (n = 5). The majority of the accrued samples were of Han Chinese descent: controls (n = 72) and cases (n = 4). All cases and controls were genotyped at four HLA genes, namely HLA-A, HLA-B, HLA-C, and HLA-DRB1. In comparing the samples of Han Chinese descent (72 controls and 4 cases), we found significant associations with HLA-A*33:03 (p = 0.002) and HLA-B*58:01 (p = 0.023). There was no significant association with any HLA-C or HLA-DRB1 alleles.

CONCLUSIONS

This study reveals that the occurrence of SJS/TEN in Han Chinese patients receiving strontium ranelate is HLA associated. This has important clinical implications for understanding the underlying mechanisms for this ADR as well as evaluating the potential role of genetic pre-screening for osteoporotic patients who may be prescribed strontium ranelate.

Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

We demonstrate coherent three-dimensional terahertz imaging by frequency modulation of a quantum cascade laser in a compact and experimentally simple self-mixing scheme. Through this approach, we can realize significantly faster acquisition rates compared to previous schemes employing longitudinal mechanical scanning of a sample. We achieve a depth resolution of better than 0.1 μm with a power noise spectral density below -50  dB/Hz, for a sampling time of 10  ms/pixel.

Active phase-nulling of the self-mixing phase in a terahertz frequency quantum cascade laser

We demonstrate an active phase-nulling scheme for terahertz (THz) frequency quantum cascade lasers (QCLs) under optical feedback, by active electronic feedback control of the emission frequency. Using this scheme, the frequency tuning rate of a THz QCL is characterized, with significantly reduced experimental complexity compared to alternative approaches. Furthermore, we demonstrate real-time displacement sensing of targets, overcoming the resolution limits imposed by quantization in previously implemented fringe-counting methods. Our approach is readily applicable to high-frequency vibrometry and surface profiling of targets, as well as frequency-stabilization schemes for THz QCLs.

The role of intravenous immunoglobulin in toxic epidermal necrolysis: a retrospective analysis of 64 patients managed in a specialized centre

BACKGROUND

Toxic epidermal necrolysis (TEN) is a severe cutaneous adverse drug reaction with a mortality of 40%. Intravenous immunoglobulin (IVIg) is widely used as a specific treatment for this reaction, although evidence of its benefit is conflicting.

OBJECTIVES

We sought to evaluate whether the use of IVIg improved mortality in patients with Stevens-Johnson syndrome (SJS)/TEN overlap and TEN.

METHODS

We retrospectively analysed data for 64 patients with SJS/TEN overlap and TEN who were treated with IVIg at a single referral centre. The primary outcome analysed was in-hospital mortality. Predicted mortality was calculated based on severity-of-illness score for TEN (SCORTEN) values. Secondary analyses of survival based on IVIg dosages and prior corticosteroid exposure were also performed.

RESULTS

There were 28 cases of SJS/TEN overlap and 36 cases of TEN, with a mean SCORTEN value of 2·6. The mean dose of IVIg given was 2·4 g kg(-1) and the mean delay from the onset of epidermal detachment to administration of IVIg was 3·2 days. There were 20 deaths (31%) in our cohort. The standardized mortality rate was 1·10 (95% confidence interval 0·62-1·58). Subgroup analysis comparing survivors and nonsurvivors showed a higher SCORTEN in nonsurvivors (3·4 vs. 2·2). There were no differences with regard to the dosage, delay and duration of IVIg administration. When stratified according to dosage, there was no mortality difference between patients who receive high-dose (≥ 3 g kg(-1) ) vs. low-dose (< 3 g kg(-1) ) IVIg.

CONCLUSIONS

This study shows that the use of IVIg does not yield survival benefits in SJS/TEN overlap and TEN, even when corrected for IVIg dosages.

Terahertz inverse synthetic aperture radar imaging using self-mixing interferometry with a quantum cascade laser

We propose a terahertz (THz)-frequency synthetic aperture radar imaging technique based on self-mixing (SM) interferometry, using a quantum cascade laser. A signal processing method is employed which extracts and exploits the radar-related information contained in the SM signals, enabling the creation of THz images with improved spatial resolution. We demonstrate this by imaging a standard resolution test target, achieving resolution beyond the diffraction limit.

Mortality of bullous pemphigoid in Singapore: risk factors and causes of death in 359 patients seen at the National Skin Centre

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune-mediated subepidermal blistering skin disease and is associated with significant morbidity and mortality.

OBJECTIVES

To determine the 3-year mortality rate, risk factors and causes of death in patients with BP in Singapore, compared with the general population.

METHODS

We conducted a retrospective cohort study of all newly diagnosed patients with BP seen at the National Skin Centre from 1 April 2004 to 31 December 2009. Demographic and clinical data on comorbidities and treatment were recorded. Mortality information was obtained from the National Registry of Diseases.

RESULTS

In total 359 patients were included in our study. The 1-, 2-, 3-year mortality rates were 26·7%, 38·4% and 45·7%, respectively. The 3-year standardized mortality risk for patients with BP was 2·74 (95% confidence interval 2·34-3·19) times higher than for the age- and sex-matched general population. Parkinson disease, heart failure and chronic renal disease were associated with increased mortality, while combination treatment with low-to-moderate-dose corticoste-roids and immunomodulatory agents such as doxycycline and/or nicotinamide was associated with lower mortality. Overall, infections were the most common cause of death (59·8%), with the main causes of death being pneumonia (42·7%), cardiovascular disease (14·6%) and stroke (11·6%).

CONCLUSIONS

This study confirms an increased 3-year mortality rate for patients with BP in Singapore. Risk factors for increased mortality include medical comorbidities, especially neurological, cardiac and renal diseases. Treatment with combination therapy, including the use of low-to-moderate-dose corticosteroid, appeared to decrease mortality risk in patients with BP.

Amicrobial pustulosis associated with autoimmune disease in a patient with Sjögren syndrome and IgA nephropathy

Amicrobial pustulosis associated with autoimmune disease (APAD) is a rare clinical condition, characterized by relapsing pustular eruption, affecting mainly the skin folds. Almost all previously described cases were young women with varying underlying autoimmune diseases. We report a 36-year-old woman with the interesting triad of APAD, Sjögren syndrome and IgA nephropathy. Her rashes responded to oral prednisolone and cyclophosphamide.

Discrepancy between computed tomography coronary angiography and selective coronary angiography in the pre-stenting assessment of coronary lesion length

We aimed to compare the lesion length measured on computed tomography coronary angiography (CT-CA) with the selective coronary angiography (SCA) lesion length measured on quantitative coronary angiography (QCA). Compared with SCA, CT-CA has the advantage of showing the lumen and the atherosclerotic plaque in the arterial wall. This prospective observational study involved 44 coronary lesions. Computed tomography coronary angiography was carried out with an electrocardiogram-gated 16-slice CT before percutaneous coronary intervention. A cardiologist and a radiologist measured CT lesion lengths in consensus, whereas an interventional cardiologist carried out QCA to obtain SCA lesion lengths independently. The median difference of (CT lesion length - SCA lesion length) was 9.84 mm (95%CI: [7.26, 13.34]). The median difference of (stent length - SCA lesion length) was 7.68 mm (95%CI: [6.29, 9.26]); the median difference of (stent length - CT length) was -2.63 mm (95%CI: [-5.80, 0.05]). The mean ratio of stent length to SCA lesion length was 2.07 (95%CI: [1.83, 2.30]). The mean ratio of stent length to CT-CA lesion length was 0.97 (95%CI: [0.83, 1.11]). In the subgroup of drug-eluting stents (17 lesions), the median difference of (stent length - SCA lesion length) was 9.76 mm (95%CI: [6.59, 13.28]); the median difference of (stent length - CT length) was -5.2 mm (95%CI: [-11, 0.5]). The mean ratio of stent length to CT-CA lesion length was 0.93 (95%CI: [0.68, 1.17]). Computed tomography lesion length was substantially longer than SCA lesion length measured by QCA. Routine practice of choosing stent length based on QCA may underestimate the actual length of target lesion. This may lead to incomplete coverage of the target lesion, particularly when drug-eluting stents are used.

Non-invasive computed tomography angiography in the assessment of coronary stent patency: an Australian experience

BACKGROUND

This study aimed to evaluate the feasibility and accuracy of 16-slice computed tomography (CT) in the assessment of coronary stent patency. CT coronary angiography (CA) has a high degree of accuracy in the assessment of coronary artery disease compared with invasive selective CA. However, its accuracy in the evaluation of stent patency is not well investigated.

METHODS

We conducted a retrospective observational study of paired CT coronary angiography (CT-CA) and invasive fluoroscopic coronary angiography (FCA) in 37 patients with 47 coronary stents. CT-CA was carried out with an electrocardiogram-gated 16-slice CT (LightSpeed-16, General Electric (GE), WI, USA). Two CT reporters, blinded to the FCA findings, assessed CT images for stent patency. A cardiologist blinded to CT findings reported FCA. FCA was regarded as the reference standard.

RESULTS

A CT-CA could assess 45 of 47 coronary stents (96%). Non-assessable stents on CT-CA were due to motion artefacts and stent-blooming effects. Of those 45 assessable stents, CT-CA correctly identified five out of seven stents with binary in-stent restenosis (ISR) and 37 of 38 stents without binary ISR. The sensitivity and specificity of 16-slice CT in the evaluation of coronary stents for binary ISR were 71% (95% confidence interval (CI) (29%, 96%)) and 97% (95%CI (86%, 100%)), respectively, exclusive of non-assessable stents. The positive and negative predictive values of 16-slice CT were 83% (95%CI (36%, 100%)) and 95% (95%CI (83%, 99%)), respectively.

CONCLUSION

Sixteen-slice CT has a low sensitivity, but very a high specificity when compared with FCA in the evaluation of coronary stents for ISR.

Diagnostic accuracy of 16-slice CT coronary angiography in the evaluation of coronary artery disease

Multislice CT coronary angiography (CT-CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16-slice CT in the diagnosis of significant coronary stenosis (>or=50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16-slice CT-CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT-CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT-CA findings assessed FCA by visual estimation. Of 1,161 coronary segments assessable on FCA, 1,103 segments (95%) were assessable on CT-CA. The CT-CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT-CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient-based analysis, CT-CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT-CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16-slice CT-CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT-CA would appear to be a useful 'rule-out' test for patients with low-risk profile for ischaemic heart disease.

Possible role of gadolinium in nephrogenic systemic fibrosis: report of two cases and review of the literature

Nephrogenic systemic fibrosis/nephrogenic fibrosing dermopathy (NSF/NFD) is a rare fibrosing disorder that occurs in patients with renal failure. It is associated with significant mortality and morbidity. Patients typically present with painful or pruritic indurated plaques involving the limbs and trunk, with sparing of the face. Severity and rapidity of cutaneous progression correlate with poorer prognosis. To date, the management of NSF/NFD remains anecdotal. The aetiological link in NSF/NFD is also yet to be confirmed, but renal dysfunction seems a common feature. Following recent reports of a possible causative role of gadolinium, we present two patients with histologically confirmed NSF/NFD, who had exposure to gadolinium-containing contrast agents 1-2 months before onset of disease. Severity of renal impairment, lack of immediate dialysis after exposure and cumulative dose of gadolinium are possible factors influencing the development of NSF/NFD. The process of transmetallation of gadolinium chelates may occur in patients with renal impairment, leading to precipitation of free gadolinium in the dermis or other organs, causing tissue injury that ultimately leads to the clinical manifestations of NSF/NFD. Although the causative role is not proven, gadolinium-containing contrast agents should be used only if clearly necessary in patients with renal failure.

Cutaneous injuries from marine animals

Cutaneous injuries by marine animals have a myriad of clinical presentations. Most require only symptomatic treatment, but some may be limb-threatening or even fatal. This is a report of three cases of marine animal injuries by a stingray, a sea anemone and a jellyfish, respectively, illustrating the potential severity of such injuries. The importance of early diagnosis is emphasised, with a discussion on the management of injuries from these three types of marine animals.

Non-invasive multislice computed tomography coronary angiography for imaging coronary arteries, stents and bypass grafts

Abstract Multislice computed tomography (MSCT) is evolving rapidly and available data suggest that MSCT coronary angiography may be a reliable and accurate non-invasive imaging modality of coronary arteries. Current generations of MSCT scanners have high sensitivity and specificity for diagnosing native coronary artery disease and coronary bypass graft occlusion. The performance of MSCT in the evaluation of stent patency is still being assessed. In comparison with conventional selective coronary angiography (SCA), MSCT is non-invasive, cheaper and it has the advantages of imaging plaque compositions as well as assessment of luminal patency. Nevertheless, the role of MSCT in the management of coronary artery disease is yet to be fully defined.

Serious cutaneous adverse reactions to traditional Chinese medicines

INTRODUCTION

Serious cutaneous adverse reactions to traditional medicines are not well described or reported in the literature, despite growing use of these medicines.

METHODS

This is a case series of four patients who were found to have various serious cutaneous adverse reactions to the traditional Chinese medicines that they had taken.

RESULTS

In this series, there was a patient with toxic epidermal necrolysis from traditional Chinese medicine, another with acute generalised exanthematous pustulosis from piroxicam and salicylate-contaminated traditional Chinese medicine, and two patients with drug hypersensitivity syndrome--one from traditional Chinese medicine and the other from phenylbutazone-adulterated traditional Chinese medicine.

CONCLUSION

The series illustrates that serious cutaneous adverse reactions do occur with traditional medicines and emphasises the importance of being aware of such reactions.

Restenosis in percutaneous coronary intervention--is drug-eluting stent the answer?

The long-term success of percutaneous coronary intervention in the treatment of coronary artery disease is hampered by the occurrence of restenosis, which often necessitates repeat hospitalisations or coronary interventions. The advent of drug-eluting stents, particularly those coated with sirolimus and paclitaxel, may be the breakthrough in the battle against restenosis that interventional cardiologists have been waiting for, and we review the currently available evidence for this. Despite the growing enthusiasm, we should not forget that this new technology is still in its relative infancy, and there remain many unanswered questions, particularly about the long-term effect of using these stents.

Skeletal myoblast transplant in heart failure

Despite recent advances in the prevention and treatment of ischemic heart disease (IHD), treatment of patients with heart failure secondary to myocardial infarction remains a therapeutic challenge. Heart transplantation has emerged as a viable option but is fraught with problems of supply. Mechanical assist devices are extremely expensive and dynamic cardiomyoplasty has shown only limited success in the clinical setting. Recent insights into the pathogenesis of myocardial diseases and the progress made in the field of molecular biology have resulted in the development of new strategies at molecular as well as cellular levels for cardiac muscle repair. One such strategy is to augment ventricular function by means of cellular cardiomyoplasty through intracardiac cell grafting using adult and fetal cardiomyocytes, stem cells, and autologous skeletal myoblasts.

Factors contributing to variation in lipoprotein (a) in Melbourne Anglo-Celtic population

AIM

The purpose of this report is to survey the factors contributing to variation in lipoprotein(a) (Lp(a)) in a population-based sample of Anglo-Celtic Melburnians.

RESULTS

The plasma Lp(a) levels were highly skewed towards low levels in this population, with a median of 156 mg/l and a mean of 262 mg/l. Approximately 33% had plasma Lp(a) above the threshold value of 300 mg/l, while 35% had Lp(a) levels below 100 mg/l. The most commonly occurring phenotype was apo(a) S3. In this phenotype, Lp(a) concentrations ranged from 10 to 596 mg/l. Lp(a) was consistently associated with diastolic blood pressure, systolic blood pressure, total protein, albumin and nitrogen excretion in the 40-60 y age group. Multiple stepwise regression analyses, in non-dietary factors, were used to explain about 13% of the variance in Lp(a) (19% in men and 23% in women). Remarkably, in the <40 y age group, non-dietary factors may account for 86% of the variance in Lp(a) and dietary factors, analysed separately, 46%. Thus, although Lp(a) is mainly genetically determined, there are clearly other factors which contribute to variations in Lp(a) concentrations.

Clinical outcomes of patients with diabetes mellitus and acute myocardial infarction treated with primary angioplasty or fibrinolysis

OBJECTIVE

To compare the early and late outcomes of primary percutaneous transluminal coronary angioplasty (PTCA) with fibrinolytic treatment among diabetic patients with acute myocardial infarction (AMI).

DESIGN

Retrospective observational study with data obtained from prospective registries.

SETTING

Tertiary cardiovascular institution with 24 hour acute interventional facilities.

PATIENTS

202 consecutive diabetic patients with AMI receiving reperfusion treatment within six hours of symptom onset.

INTERVENTIONS

Fibrinolytic treatment was administered to 99 patients, and 103 patients underwent primary PTCA. Most patients undergoing PTCA received adjunctive stenting (94.2%) and glycoprotein IIb/IIIa inhibition (63.1%).

MAIN OUTCOME MEASURES

Death, non-fatal reinfarction, and target vessel revascularisation at 30 days and one year were assessed.

RESULTS

Baseline characteristics were similar in these two treatment groups except that the proportion of patients with Killip class III or IV was considerably higher in those treated with PTCA (15.5% v 6.1%, p = 0.03) and time to treatment was significantly longer (103.7 v 68.0 minutes, p < 0.001). Among those treated with PTCA, the rates for in-hospital recurrent ischaemia (5.8% v 17.2%, p = 0.011) and target vessel revascularisation at one year (19.4% v 36.4%, p = 0.007) were lower. Death or reinfarction at one year was also reduced among those treated with PTCA (17.5% v 31.3%, p = 0.02), with an adjusted relative risk of 0.29 (95% confidence interval 0.15 to 0.57) compared with fibrinolysis.

CONCLUSION

Among diabetic patients with AMI, primary PTCA was associated with reduced early and late adverse events compared with fibrinolytic treatment.

Therapeutic angiogenesis for coronary artery disease

Therapeutic angiogenesis may be a realistic approach in treating ischemic heart disease. VEGF is a major angiogenic factor involved in physiological as well as pathological angiogenesis. The ability of VEGF to promote angiogenesis in animal and clinical studies has been studied extensively. However, it is becoming clear that VEGF alone may not be sufficient to effectively complete the angiogenesis process. The use of more than one growth factor may be more pertinent in creating a sustainable angiogenic effect with clinically significant outcome. The challenge is to find complementary partners in angiogenesis to better affect the outcome of the process. To this end, we have been studying the effects of other angiogenic factors such as angiopoietin-1 (Ang-1) in a chronic ischemic porcine model. Single intramyocardial introduction of adenovirus-mediated gene transfer of Ang-1 into the left ventricle free wall has been found to enhance angiogenesis by augmenting the formation of new capillaries that manifested in improved total blood flow in the myocardium. A combined therapeutic angiogenesis study involving VEGF and Ang-1 is currently underway. Due to their unique complementary properties, it is expected that the combination will not merely enhance angiogenesis but will also lead to healthy and mature vascular network in the ischemic myocardium.

Gender differences in outcome after an acute myocardial infarction in Singapore

OBJECTIVES

To characterise gender and age-related differences in presentation and outcome after an acute myocardial infarction (AMI).

DESIGN

Data were derived retrospectively from the Singapore Myocardial Infarction Registry from 1988 through 1997. This database comprised all AMI cases for ages between 20 and 64 years (group A). For approximately three months a year, data were also collected for all AMI cases above the age of 64 years (group B). There were 13,048 and 4,425 cases in groups A and B respectively.

RESULTS

In age - standardised AMI rates, males outnumbered females by a factor of 4.0 and 1.7 for groups A and B respectively.The median age of presentation was higher in females for both age groups being 58 years versus 54 years for group A and 75 years versus 72 years for group B. Younger females had worse survival at 28 days and were more likely to have prior ischaemic heart disease and require resuscitation. They were also more likely to have atypical symptoms. Previous myocardial infarction was not different between the sexes in both groups. Among the older age group, there was no gender difference in prior ischaemic heart disease, 28-day survival and requirement for resuscitation.

CONCLUSION

Women who have AMI tend to be older than men. Gender differences are age-specific. Women who are 64 years and below have more atypical symptoms, prior ischaemic heart disease and worse prognosis than men after AMI. These differences are not seen in those over the age of 64.

Alpha1A- and alpha1B-adrenoceptors are the major subtypes in human saphenous vein

In this study we analyzed the different alpha1-adrenoceptor (AR) subtypes present in human saphenous vein (HSV) using reverse transcription polymerase chain reaction (RT-PCR), DNA-DNA hybridization analysis and functional affinities for alpha-AR antagonists. DNA-DNA hybridization analysis of RT-PCR amplification products confirmed the presence of alpha1A- and alpha1B-ARs, and low levels of alpha1D-AR in HSV. The functional results showed: (1) prazosin, the selective alpha1-AR antagonist, phentolamine, the alpha1- and alpha2-ARs antagonist, WB 4101 and 5-MU, the selective alpha1A-AR subtype antagonists were potent, competitive antagonists of noradrenaline (NA)-induced contraction (pA2 values of 11.03, 8.06, 9.02 and 8.34, respectively). (2) Alpha1-AR-induced contraction was sensitive to the alkylating effects of CEC (the alpha1B and alpha1D-AR subtypes antagonist) and (3) The selective alpha1D-AR subtype antagonist BMY displayed low affinity (pA2 values of 6.44). This indicates that the contractile response of the HSV to alpha1-AR-induced is predominantly mediated by both alpha1A and alpha1B-AR subtypes. This was also supported by the good relationship between pA2 values from the present study and reported binding affinities (pKi) values of various alpha1-AR subtype antagonists with cloned human alpha1A- and alpha1B-AR subtypes (r=0.89 and r=0.98, respectively), but not the alpha1D-AR subtype (r=0.67). Our results indicate that alpha1A- and alpha1B-ARs are the main functional and expressed receptor subtypes in HSV.

Effects of micromolar concentrations of manganese, copper, and zinc on alpha1-adrenoceptor-mediating contraction in rat aorta

To determine the influences of the Mn, Cu, and Zn on alpha1-adrenoceptor (AR)-mediated vasoconstriction, we investigated their effects on vasoconstriction produced by the alpha1-AR agonist phenylephrine in isolated rings of rat thoracic aorta. The cumulative concentration-contraction curves for phenylephrine were obtained in the absence and presence of Mn (0.3, 1, 3 microM), Cu (1, 10, 16 microM), and Zn (0.3, 1, 10 microM). Mn, Cu, and Zn each inhibited phenylephrine-mediated contraction in a dose-dependent manner. The maximal phenylephrine-induced contraction was significantly reduced by the pretreatment of the arterial rings with 10 and 16 microM Cu (p<0.05). The results suggest that variations in the plasma concentrations of metal might lead to changes in alpha1-AR-mediated constrictive response.

Cost-effectiveness and accuracy of exercise stress echocardiography in the non-invasive diagnosis of coronary heart disease

BACKGROUND

Exercise stress echocardiography (ESE) is a more recent form of totally non-invasive stress testing which like exercise thallium SPECT scintigraphy (ETS) was developed to overcome the known limitations of ECG stress testing, namely the limited diagnostic accuracy and the inability of ECG stress testing to site the region of coronary artery disease (CAD) induced ischaemia.

AIMS

To determine the sensitivity and specificity (and overall accuracy) of ESE in a group of patients referred for ETS imaging and compare the relative costs of each technique.

METHODS

One hundred and fifteen patients referred for ETS consented to a simultaneous ESE. Of this group, 59 patients underwent coronary angiography which was utilised as the gold standard.

RESULTS

The feasibility of ESE was 97% (112 of 115 patients of the total study population and 57 of the 59 patients who underwent coronary angiography). Of the 59 patients undergoing coronary angiography, the sensitivity of ESE and ETS were not significantly different (84.1% versus 91.3% respectively). However, despite the apparent marked difference in specificity (92.3% versus 61.5% respectively), p = NS (Fisher's exact test) as there were only 13 normals in the group who underwent coronary angiography. Overall accuracy was also closely similar (86.0% versus 84.7% respectively) and therefore also not significantly different. By contrast, agreement with coronary angiography as measured by the kappa statistic (kappa +/- SEk) was good for ESE (0.66 +/- 0.11) but only moderate for ETS (0.54 +/- 0.13). Moreover, there was a cost saving of at least $594.00 per patient in favour of ESE.

CONCLUSION

ESE is a totally non-invasive, sensitive, specific and cost-effective imaging modality for the detection and localisation of CAD.

120-W continuous-wave diode-pumped Tm:YAG laser

We present a 120-W cw diode-pumped Tm:YAG laser. The Tm:YAG rod is side pumped by three diode arrays whose radiation is coupled through compound parabolic concentrators. The maximum optical-to-optical conversion efficiency of the 2.02-mum laser output is 25.2%, with a slope efficiency of 31.2%.

Compact 21-W 2-mum intracavity optical parametric oscillator

We report on an intracavity optical parametric oscillator (OPO) placed within a compact diode-pumped Nd:YALO laser cavity. This OPO utilizes a pair of KTP crystals, which are diffusion bonded together in a walk-off-compensated configuration. We have generated up to 21.4 W of 2-mum radiation, operating in a few-kilohertz range.

Stent placement for non-STRESS/BENESTENT lesions: a critical review

Stenting lesions with favorable characteristics as required for inclusion in the STRESS/BENESTENT trials have yielded superior results to that of PTCA alone. Results for less favorable lesions such as in small vessels, diffuse disease, ostial disease, and saphenous vein grafts are less well established. This review seeks to analyze available data for stent placement in this subset of non-STRESS/BENESTENT lesions.

Inhibition of restenosis with beta-emitting radiotherapy: Report of the Proliferation Reduction with Vascular Energy Trial (PREVENT)

BACKGROUND

Intracoronary gamma- and beta-radiation have reduced restenosis in animal models. In the clinical setting, the effectiveness of beta-emitters has not been studied in a broad spectrum of patients, particularly those receiving stents.

METHODS AND RESULTS

A prospective, randomized, sham-controlled study of intracoronary radiotherapy with the beta-emitting (32)P source wire, using a centering catheter and automated source delivery unit, was conducted. A total of 105 patients with de novo (70%) or restenotic (30%) lesions who were treated by stenting (61%) or balloon angioplasty (39%) received 0 (control), 16, 20, or 24 Gy to a depth of 1 mm in the artery wall. Angiography at 6 months showed a target site late loss index of 11+/-36% in radiotherapy patients versus 55+/-30% in controls (P:<0.0001). A low late loss index was seen in stented and balloon-treated patients and was similar across the 16, 20, and 24 Gy radiotherapy groups. Restenosis (>/=50%) rates were significantly lower in radiotherapy patients at the target site (8% versus 39%; P:=0.012) and at target site plus adjacent segments (22% versus 50%; P:=0.018). Target lesion revascularization was needed in 5 radiotherapy patients (6%) and 6 controls (24%; P:<0.05). Stenosis adjacent to the target site and late thrombotic events reduced the overall clinical benefit of radiotherapy.

CONCLUSIONS

beta-radiotherapy with a centered (32)P source is safe and highly effective in inhibiting restenosis at the target site after stent or balloon angioplasty. However, minimizing edge narrowing and late thrombotic events must be accomplished to maximize the clinical benefit of this modality.

Cardiac marker point-of-care testing: evaluation of rapid on-site biochemical marker analysis for diagnosis of acute myocardial infarction

INTRODUCTION

Up to 40% of patients with acute myocardial infarction (AMI) present with non-diagnostic electrocardiograms (ECGs). The diagnosis in such cases is usually made with the aid of biochemical markers. Newer and more rapid assays for such markers have now enabled testing to be done on-site instead of in the laboratory. This potentially enables the clinician to rapidly diagnose and triage patients. We evaluated the diagnostic precision of this point-of-care testing strategy using one such analyser, the Stratus CS (Dade Behring) in a prospective study.

MATERIALS AND METHODS

The study population consisted of 51 consecutive patients admitted for suspected AMI with non-diagnostic ECGs. Two blood samples from each patient were drawn simultaneously on admission. The first sample was assayed for myoglobin, troponin I (TnI) and creatine kinase-MB (CKMB) mass by the point-of-care instrument (Stratus CS), and the second sample was sent for standard testing for AMI, comprising a troponin-T (TnT) qualitative test and the analysis of CKMB by the hospital laboratory. Utilising the recommended cut-off values for the individual assays, the results of these 2 sets of tests were evaluated based on whether they were positive or negative for AMI and compared against the patient's final diagnosis at discharge. Various combinations of markers were assessed.

RESULTS

On evaluation of individual markers, myoglobin was the most sensitive (75%) at 0 to 6 hours after onset of symptoms, while TnI (95%), TnT (80%) and CKMB-mass (90%) performed better at 7 to 12 hours. Point-of-care testing utilising a combination of markers was highly sensitive and specific. Both dual-marker panels of myoglobin with TnI and myoglobin with CKMB-mass yielded equivalent overall sensitivities and specificities of 90% and 95% respectively. A triple-marker panel of myoglobin, TnI and CKMB-mass had a sensitivity of 93% and specificity of 95%. All point-of-care testing panels had good positive and negative predictive values, and showed comparable diagnostic efficacy with the standard testing presently utilised for the diagnosis of AMI. The average time for results to become available was up to 26 minutes for point-of-care testing and 65 minutes for standard testing.

CONCLUSION

Point-of-care testing utilising a panel of 2 or 3 cardiac markers has comparable diagnostic precision to the presently utilised testing strategy for AMI, with earlier availability of results.

Room-temperature operation of a multiwatt Tm:YAG laser pumped by a 1-mum Nd:YAG laser

We present what is to our knowledge the first demonstration of a 4.7-W cw Tm:YAG. This proof-of-principle experiment clearly demonstrates the possibility of using a pump absorption that is 2 orders of magnitude (~0.0078 cm(-1)) less than that of the conventional pump absorption (typically >1 cm(-1)). This Tm:YAG laser is pumped intracavity within a Nd:YAG laser for multiple-pass absorption. The maximum conversion efficiency of 2.02 mum is 20%, with a slope efficiency of 35% with respect to the absorbed 1.064-mum power.

Treatment and prevention of sudden cardiac death--what have we learnt from randomised clinical trials?

Sudden cardiac death is most commonly caused by ventricular tachycardia or fibrillation. Three groups of patients at highest risk for sudden cardiac death are survivors of previous sudden cardiac death, those with recurrent documented episodes of sustained ventricular tachycardia and patients with recurrent syncope of unknown origin. The experience with antiarrhythmic drugs has been discouraging. Only beta-blockers have been shown to unequivocally reduce both arrhythmic and total mortality in randomised trials. Class I antiarrhythmic drugs increase mortality, especially in an ischemic substrate. Class III drugs such as sotalol and amiodarone have had variable success. Racemic sotalol has both beta-blocker as well as Class III actions and some of the benefits may be due to the former effect. D-sotalol which has only pure Class III action, increases mortality in the post myocardial infarction patient. Amiodarone is superior to Class I antiarrhythmic drugs for patients with previous cardiac arrest. In the high-risk myocardial infarction patient, it seems to reduce sudden death but not total mortality. In the cardiac failure patient, the effect of amiodarone on total mortality is controversial. Several randomised trials of implantable cardioverter-defibrillator (ICD) therapy versus drugs have however concluded that the ICD is superior to drugs in reducing total mortality. In comparison with many other high volume therapies used in medicine today, ICD is still a cost-effective therapy.

Immediate and mid-term results after MultiLink stent implantation in native coronary arteries

Different stent designs have widely disparate characteristics that may exert a positive or negative impact on their early and mid-term outcomes. The MultiLink stent (Guidant/Advanced Cardiovascular Systems, Santa Clara, CA) is a new coronary stent with only very limited data. In this report, we examined the results of 50 consecutive patients treated with 57 premounted sheathless MultiLink stents in 53 native coronary arteries with reference diameter > or =2.7 mm. Successful stenting was achieved in 98% of patients, resulting in an improvement in diameter stenosis from 91%+/-11% to 1%+/-3% (P = 0.0001). At 1 month, there was no death, myocardial infarction, or stent thrombosis. Angiographic restudy at a mean of 5.0+/-1.8 months in 94% of patients revealed an in-stent restenosis rate of 20.7%. The restenosis rates for diabetic patients (vs. nondiabetic patients), type C lesions (vs. type A/B1 lesions), and the use of 35-mm-long stents (vs. 15-mm-long stents) were 45.4% (14.3%), 56% (< or =11%), and 80% (8.8%), respectively (P < 0.05). In conclusion, the present study demonstrates that the MultiLink stent has an excellent performance profile, is associated with a low risk of stent thrombosis in native coronary vessels, and yields a favorable restenosis rate, particularly after the use of short (15 mm) stents to treat simple lesions.

Curative therapy of cardiac tachyarrhythmias with catheter ablation--a review of the experience with the first 1000 patients

INTRODUCTION

Cardiac tachyarrhythmias present as supraventricular or ventricular tachycardia. Catheter ablation has completely revolutionised the treatment of patients with these arrhythmias.

METHOD

We reviewed the experience of radiofrequency catheter ablation in a single centre.

RESULTS

A total of 1,022 patients underwent radiofrequency catheter ablation from October 1991-December 1997. There were 480 patients who had AV nodal re-entrant tachycardia, 429 patients with accessory pathways, 7 patients with both AV nodal re-entrant tachycardia and accessory pathways, 4 patients with both AV nodal re-entrant tachycardia and atrial tachycardia. Twenty-seven patients had atrial tachycardia ablation, 28 had atrial flutter ablation and 11 patients had AV node ablation for atrial fibrillation. The mean age of the supraventricular tachycardia patients was 41 +/- 15 years (10-80 years). The mean duration of procedure was 108 +/- 60 minutes (15 to 480 minutes) and the mean fluoroscopy time was 19 +/- 17 minutes (3-122 minutes). Another 14 patients had ablation for right ventricular outflow tract ventricular tachycardia and 22 patients had ablation for idiopathic left ventricular tachycardia. The mean age of the ventricular tachycardia patients was 35 +/- 14 years (19-65 years). The mean duration of the ventricular tachycardia ablation procedure was 185 +/- 63 minutes (110-285 minutes) and the duration of fluoroscopy was 33 +/- 16 minutes (range 14-68 minutes). Of the 1,022 patients, 1,002 (98%) of the patients were successfully ablated. There were significant complications in less than 1% of the patients and no mortality associated with the procedure. The recurrence rate was 5% and could be successfully reablated when the procedure was repeated.

CONCLUSION

Radiofrequency catheter ablation is thus an extremely safe and successful procedure and has replaced drug therapy as the treatment of choice for patients with supraventricular tachycardia and non-ischaemic ventricular tachycardia. It provides curative therapy without the need for life-long drug therapy.

Angiographic restenosis rate in patients with chronic total occlusions and subtotal stenoses after initially successful intracoronary stent placement

The 5-month angiographic in-stent restenosis rate did not differ between patients with chronic total occlusions (n = 43) and subtotal stenoses (n = 43) equally matched for diabetes status, exact stent design, final expanded stent diameter, stent length, and residual percent diameter stenosis after stent placement; it was 32.5% and 27.9% for those with chronic total occlusions and subtotal stenoses, respectively (p = 0.638). Furthermore, the stent occlusion rate (4.6% vs 6.9%, respectively) was low in both patient groups.

Goldberger's triad in dilated cardiomyopathy--can it predict the severity of left ventricular dysfunction?

Goldberger's triad is a specific, but relatively insensitive, electrocardiographic sign for dilated cardiomyopathy. To study the correlation between the presence of this sign and the severity of left ventricular dysfunction, the electrocardiograms and echocardiographically-determined left ventricular parameters of 17 patients (mean age 59.3 +/- 11.8 years) with dilated cardiomyopathy were examined. Five of the patients had Goldberger's triad. We found that the mean left atrial diameter, the mean left ventricular internal diameters (both end-systolic and end-diastolic) and the mean left ventricular ejection fraction of the group of patients with Goldberger's triad did not differ significantly from the group without. Coronary angiography revealed occult coronary artery disease in 5 of 12 patients. A larger, prospective study is required to verify our finding.

Four years' experiences in the treatment of pituitary adenomas with gamma knife radiosurgery

To determine the tumor control rates and endocrinological responses after stereotactic radiosurgery for pituitary adenomas, we reviewed our experience in 65 patients (40 men, 25 women) treated in the Gamma Knife during the last 4 years. The mean age was 41.6 years (range 19-69 years). 43 patients had endocrinologically active tumors (20 growth hormone-secreting, 19 prolactin-secreting and 4 ACTH-secreting adenomas). 22 had nonfunctioning adenomas. 39 patients had a macroadenoma and 26 patients had a microadenoma. 33 patients underwent Gamma Knife radiosurgery for recurrent or residual tumors after microsurgery. 50 patients have had follow-up neuroimaging studies and/or hormonal evaluation. The follow-up period was 25.5 months (range 3 to 54 months). The margin of the tumor was incorporated within the 50 to 90% isodose. The mean number of isocenters was 3.8 and the mean marginal dose was 25.4 Gy (range 15 to 36 Gy). 27 out of 40 patients (65.7%) showed decreased tumor volume to less than 50% of the initial volume. In 17 out of 38 patients (44.7%) with endocrinologically active tumors, the hormonal level fell to within the normal range. Two patients had delayed complications: in one case there was pituitary insufficiency and in the other a visual disturbance. Gamma Knife radiosurgery seems to be effective adjuvant therapy for pituitary adenoma in selected cases. More long-term follow-up is required to evaluate the efficacy and side effects further.

The Brugada syndrome in a Chinese population

Sudden cardiac death has been reported in patients with a unique electrocardiographic (ECG) abnormality showing right bundle branch block and ST segment elevation in the precordial leads. This syndrome was first described by Brugada and Brugada and has not been previously described in a Chinese population. We report here the first three cases in Singapore. The first patient was a 49-year-old man who presented with syncope, associated with generalized convulsions. The second patient was a 25-year-old man who complained of palpitations but no syncope. The third patient was a 77-year-old man who presented with recurrent episodes of syncope and collapsed with ventricular fibrillation. All patients had no past cardiac or drug history of note. The neurological examination and investigations were normal. All three patients showed a unique right bundle branch block pattern with ST segment elevation in leads V1-3. The echocardiogram and 24-h ambulatory ECG monitoring, were normal. Single vessel disease was present in the third patient. Electrophysiological studies performed in all three patients were able to induce ventricular fibrillation. The patient with resuscitated cardiac death underwent an implantable cardioverter defibrillator implantation. The importance of this syndrome is that the recognition of the unique ECG pattern enables early identification and treatment of these patients.

Midterm angiographic outcome of single-vessel intracoronary stent placement in diabetic versus nondiabetic patients: a matched comparative study

BACKGROUND

It remains controversial whether diabetes is associated with an increased risk of restenosis after intracoronary stenting.

METHODS AND RESULTS

We selected 42 diabetic patients and an equal number of nondiabetic patients with follow-up angiographic restudy after single-vessel stenting, matched for 4 important stent-related and angiographic variables (stent design, reference vessel size and expanded stent diameter, coronary vessel treated, and poststent residual diameter stenosis). The 2 patient groups did not differ in their baseline lesion severity and acute luminal gain. At 5-month angiographic assessment, the observed in-stent restenosis rate was significantly higher in diabetic than nondiabetic patients (40.5% vs 16.7%, P = 0.0157). It was highest in diabetic patients who received small stents <3.0 mm in diameter and intermediate in diabetic patients who received larger stent sizes (55% vs 27%, P = 0.0675). The frequency of restenosis in nondiabetic patients, however, was low; it was 18% and 15% in those who received small stents and larger stents, respectively (P = 0.7823).

CONCLUSIONS

Our data suggest that diabetes predisposes to an increased risk of in-stent restenosis, particularly in small vessels.

Percutaneous transluminal coronary angioplasty (PTCA) without on-site surgical facilities

BACKGROUND

Numerous publications from European and Canadian centres have documented the feasibility of performing percutaneous transluminal coronary angioplasty (PTCA) without on-site surgical facilities. The absolute need for surgical standby has been changing especially with the introduction of coronary stent for bailout situations. This practice may be applicable in Australian centres especially in the environment of long waiting lists and cost containment.

AIM

To review the safety of performing PTCA by experienced operators in two Melbourne hospitals without on-site surgical facilities.

METHODS

We reviewed data of all patients who had PTCA electively (with low and moderate risks) between July 1996 and January 1997 and in the setting of acute myocardial infarction (AMI) from January 1996 to January 1997. Surgical standby was available as 'next available room' basis in nearby centres. Immediate outcome before discharge was documented and follow up from three to six months in 80% of all surviving patients.

RESULTS

There were 46 elective PTCA and 41 PTCA for AMI. PTCA was successful in 82 (94%) patients. Among the elective cases, seven patients were already inpatients with unstable or postinfarct angina. Thirteen patients had stents deployed with three for acute closure. Abciximab (Reopro) was given to eight patients. Two patients had acute closure in the laboratory which could not be reopened, but did not require emergency coronary artery bypass grafting (CABG). There were four inhospital deaths (three related to AMI and one died of a noncoronary cause).

CONCLUSION

PTCA can be performed electively in a selected group of patients with coronary artery disease and as a primary procedure for AMI without on-site surgical standby.