Sudden coronary death. Frequency of active coronary lesions, inactive coronary lesions, and myocardial infarction

Fighting against sudden death: A single or multidisciplinary approach

There are many causes of sudden death ranging from accidents and suicide to vascular events and arrhythmias. Most sudden deaths will occur in people who have not been diagnosed with a serious heart condition but at a very low annual rate. Many of these events are probably vascular and might be prevented by reducing the risk of developing coronary disease. Only a minority of sudden deaths occur in people with established cardiac disease, but in patients with major structural heart disease, the annual rate is high. The causes of sudden death are many in this clinical setting also, but dominated by ventricular arrhythmias and vascular events. There is good evidence that conventional treatments for heart failure, including ACE inhibitors, beta-blockers, aldosterone antagonists and cardiac resynchronization devices reduce the risk of sudden death. Evidence that statins, aspirin or revascularisation are safe or effective in patients with heart failure is currently lacking. Implantable defibrillators confer a small but definite additional survival advantage by treating arrhythmias that have not been prevented.

What are the most useful and trustworthy noninvasive anatomic markers of existing vascular disease?

Cardiovascular disease is the leading cause of mortality and morbidity in developed countries. Evidence challenges the notion that the severity of lesions on angiography is a predictor of future cardiac events. With the recognition that subclinical coronary artery stenoses are responsible for myocardial infarcts and sudden death, it may be important to identify patients with plaque characteristics that may place them at increased risk. Intravascular ultrasound, though invasive, remains the current imaging gold standard. Computed tomography, cardiac magnetic resonance, and single-photon emission CT positron emission tomography are evolving and promising modalities. Functional studies reflecting plaque temperature and molecular imaging reflecting plaque constituents are being developed. We review the pathology of the vulnerable atherosclerotic plaque and recent innovations in imaging modalities to assess plaque complication risk.

Pathology of the Vulnerable Plaque

The majority of patients with acute coronary syndromes (ACS) present with unstable angina, acute myocardial infarction, and sudden coronary death. The most common cause of coronary thrombosis is plaque rupture followed by plaque erosion, whereas calcified nodule is infrequent. If advances in coronary disease are to occur, it is important to recognize the precursor lesion of ACS. Of the three types of coronary thrombosis, a precursor lesion for acute rupture has been postulated. The non-thrombosed lesion that most resembles the acute plaque rupture is the thin cap fibroatheroma (TCFA), which is characterized by a necrotic core with an overlying fibrous cap measuring <65 microm, containing rare smooth muscle cells but numerous macrophages. Thin cap fibroatheromas are most frequently observed in patients dying with acute myocardial infarction and least common in plaque erosion. They are most frequently observed in proximal coronary arteries, followed by mid and distal major coronary arteries. Vessels demonstrating TCFA do not usually show severe narrowing but show positive remodeling. In TCFAs the necrotic core length is approximately 2 to 17 mm (mean 8 mm) and the underlying cross-sectional area narrowing in over 75% of cases is <75% (diameter stenosis <50%). The area of the necrotic core in at least 75% of cases is < or =3 mm2. These lesions have lesser degree of calcification than plaque ruptures. Thin cap fibroatheromas are common in patients with high total cholesterol (TC) and high TC/high-density lipoprotein cholesterol ratio, in women >50 years, and in those patients with elevated high levels of high sensitivity C-reactive protein. It has only recently been recognized that their identification in living patients might help reduce the incidence of sudden coronary death.

Noninvasive Assessment of Plaque Morphology and Composition in Culprit and Stable Lesions in Acute Coronary Syndrome and Stable Lesions in Stable Angina by Multidetector Computed Tomography

OBJECTIVES

The purpose of this study was to assess morphology and composition of culprit and stable coronary lesions by multidetector computed tomography (MDCT).

BACKGROUND

Noninvasive identification of culprit lesions has the potential to improve noninvasive risk stratification in patients with acute chest pain.

METHODS

Thirty-seven patients with acute coronary syndrome (ACS) or stable angina underwent coronary 16-slice MDCT and invasive selective angiography. In all significant coronary lesions two observers measured the degree of stenosis, plaque area at stenosis, and remodeling index and assessed plaque composition. Differences between culprit lesions in patients with ACS and stable lesions in patients with ACS or stable angina were determined.

RESULTS

We analyzed 40 lesions with excellent image quality in 14 patients with ACS and 9 patients with stable angina. Culprit lesions in patients with ACS (n = 14) had significantly greater plaque area and a higher remodeling index than both stable lesions in patients with ACS (n = 13) and in patients with stable angina (n = 13) (17.5 +/- 5.9 mm2 vs. 9.1 +/- 4.8 mm2 vs. 13.5 +/- 10.7 mm2, p = 0.02; and 1.4 +/- 0.3 vs. 1.0 +/- 0.4 vs. 1.2 +/- 0.3, p = 0.04, respectively). The prevalence of non-calcified plaque was 100%, 62%, and 77%, respectively, and the prevalence of calcified plaque was 71%, 92%, and 85%, respectively, in culprit lesions in patients with ACS and in stable lesions in patients with ACS or stable angina.

CONCLUSIONS

We introduce the concept of noninvasive detection and characterization of coronary atherosclerotic lesions in patients with ACS by MDCT. We identified differences in lesion morphology and plaque composition between culprit lesions in ACS and stable lesions in ACS or stable angina, consistent with previous intravascular ultrasound studies.

Lessons learnt from the autopsies of 445 cases of sudden cardiac death in adults

AIM

To determine the cause of sudden cardiac death in adults who underwent autopsy.

METHODS

Four hundred and forty-five sudden cardiac deaths occurred within 1 h of the symptoms onset, and all other cardiac and noncardiac causes having been excluded from autopsy and toxicology screening, were retrospectively identified from among 902 autopsies performed in a 2-year period on the island of Crete. The presence of acute coronary thrombi and myocardial infarction was documented macroscopically and by light microscopy and histology.

RESULTS

In all 445 cases, at least one coronary artery had evidence of moderate to advanced atherosclerosis. About two thirds were between 50 and 70 years. Men had a higher incidence than women, but with advancing age (>60 years) this difference was reduced. Myocardial infarction was found in 17 cases (11 acute; 6 acute and healed). Fifty-eight cases (13.0%) had coronary thrombi, mostly involving the left anterior descending and the right coronary arteries (81%); only six of these were associated with acute myocardial infarction.

CONCLUSION

In our population, arrhythmia was the most common cause of sudden cardiac death, while acute coronary thrombi and acute myocardial infarction were detected only in some cases. Because of the heterogeneity in the cause of sudden cardiac deaths in adults, a detailed forensic investigation may provide important information on the cause of death and help in the development of primary and secondary prevention.

Increased circulating endothelial cells in acute heart failure: Comparison with von Willebrand factor and soluble E-selectin

BACKGROUND

Circulating endothelial cells (CECs) in the peripheral blood, probably representing the most direct evidence of endothelial cell damage, are increased in myocardial infarction, unstable angina and critical limb ischaemia. As chronic heart failure is also associated with endothelial abnormalities, we hypothesised that CECs are raised in acute heart failure and that they would correlate with plasma indices of endothelial perturbation, that is, von Willebrand factor (vWf) and soluble E-selectin.

METHODS

We studied 30 patients with acute heart failure (venesected within 24 h of emergency hospital admission), 30 patients with chronic stable heart failure (venesected as out-patients, all patients in sinus rhythm with ejection fraction < or = 40%) and 20 healthy controls. CECs were quantified using epifluorescence microscopy after CD146-immunomagnetic separation and phenotyped by streptavidin/biotin immunocytochemistry. Citrated plasma was analysed for soluble E-selectin and vWf by ELISA.

RESULTS

Levels of CECs, vWf and soluble E-selectin were significantly higher (all p<0.01) in patients with heart failure compared to controls, with no significant differences between acute and chronic heart failure. CECs correlated with plasma vWf (p<0.0001) and soluble E-selectin (p = 0.022) but not ejection fraction or NYHA class. In multiple regression analysis, heart failure was the only independent predictor of raised CECs (p<0.0001). Immunoperoxidase-defined surface expression of CD34, CD45 and CD36 by CECs was <2%, 0% and 8%, respectively.

CONCLUSION

CECs, a possibly heterologous population, may be used as a novel measure of endothelial damage in acute heart failure and may have implications for the thrombotic risk associated with acute and chronic heart failure and prognosis in this condition.

In vivo intravascular ultrasound-derived thin-cap fibroatheroma detection using ultrasound radiofrequency data analysis

OBJECTIVES

The purpose of this study was to assess the prevalence of intravascular ultrasound (IVUS)-derived thin-cap fibroatheroma (IDTCFA) and its relationship with the clinical presentation using spectral analysis of IVUS radiofrequency data (IVUS-Virtual Histology [IVUS-VH]).

BACKGROUND

Thin-cap fibroatheroma lesions are the most prevalent substrate of plaque rupture.

METHODS

In 55 patients, a non-culprit, non-obstructive (<50%) lesion was investigated with IVUS-VH. We classified IDTCFA lesions as focal, necrotic core-rich (> or =10% of the cross-sectional area) plaques being in contact with the lumen; IDTCFA definition required a percent atheroma volume (PAV) > or =40%.

RESULTS

Acute coronary syndrome (ACS) (n = 23) patients presented a significantly higher prevalence of IDTCFA than stable (n = 32) patients (3.0 [interquartile range (IQR) 0.0 to 5.0] vs. 1.0 [IQR 0.0 to 2.8], p = 0.018). No relation was found between patient's characteristics such as gender (p = 0.917), diabetes (p = 0.217), smoking (p = 0.904), hypercholesterolemia (p = 0.663), hypertension (p = 0.251), or family history of coronary heart disease (p = 0.136) and the presence of IDTCFA. A clear clustering pattern was seen along the coronaries, with 35 (35.4%), 31 (31.3%), 19 (19.2%), and 14 (14.1%) IDTCFAs in the first 10 mm, 11 to 20 mm, 21 to 30 mm, and > or =31 mm segments, respectively, p = 0.008. Finally, we compared the severity (mean PAV 56.9 +/- 7.4 vs. 54.8 +/- 6.0, p = 0.343) and the composition (mean percent necrotic core 19.7 +/- 4.1 vs. 18.1 +/- 3.0, p = 0.205) of IDTCFAs between stable and ACS patients, and no significant differences were found.

CONCLUSIONS

In this in vivo study, IVUS-VH identified IDTCFA as a more prevalent finding in ACS than in stable angina patients.

[Acute coronary syndrome in the prehospital phase]

Cardiovascular diseases are the number one cause of death in Germany. In 2002 about 70,000 people died of acute myocardial infarction (AMI) and of these 37% died before arrival at hospital which underlines the relevance of adequate prehospital care. The generic term acute coronary syndrome (ACS) was introduced because a single pathomechanism accounts for the different forms and comprises unstable angina pectoris (iAP), non-ST-elevation myocardial infarction (NSTEMI), ST-elevation myocardial infarction (STEMI) and sudden cardiac death (SCD). Characteristic features are retrosternal pain, vegetative symptoms and radiation of pain into the adjoining regions. Further differentiation can only be achieved by the 12-lead ECG, as cardiac-specific enzymes do not play a role in prehospital decisions. Prehospital delays should be avoided, history and physical examination should be brief but focused, vital parameters should be assessed and monitored. Basic treatment for ACS should comprise inhalative oxygen, nitrates, morphine, aspirin and beta-blockers. If STEMI is diagnosed, patients with symptoms <12 h should undergo fibrinolytic therapy unless there is primary percutaneous coronary intervention (PCI) available within 90 min or if contraindicated. Heparin should be given to patients with STEMI depending on the choice of fibrinolytic agent, it otherwise results in a higher risk of bleeding, but in patients with iAP or NSTEMI it reduces mortality. All patients must be accompanied by the emergency physician during transportation and should be brought to a hospital with primary PCI, especially those with complicated ACS. Treatment of complications depends largely on the type, persistence and severity.

Recurrent infarction causes the most deaths following myocardial infarction with left ventricular dysfunction

PURPOSE

The development of left ventricular systolic dysfunction or heart failure following an acute myocardial infarction (MI) is a powerful marker of an adverse prognosis. Recurrent MI could be an important cause of death, either directly or by provoking arrhythmias.

METHODS

The OPTIMAAL trial randomized 5477 patients with heart failure or evidence of left ventricular dysfunction following acute MI to losartan or captopril. Over a follow-up of 2.7 years, there were 946 deaths. Of the 180 (19%) of these deaths for which autopsy reports were available, acute MI was found in 57% (102 of 180) of the autopsies. By comparison, an endpoints adjudication committee using clinical data attributed death to acute MI in only 29 cases. An acute MI was found at autopsy in 55% (37 of 67) of the deaths that had been classified as due to an arrhythmia and in 81% (21 of 26) of the deaths classified as due to progressive heart failure. Including autopsy diagnoses, the rate of acute MI in patients who died suddenly was independent of the time elapsed since the index MI, but in patients not classified as dying suddenly, there was a time-related decrease in recurrent MI from 78% in the first 30 days to 30% by the end of follow-up. However, only 19% of patients who died underwent autopsy, so recurrent MI may have been substantially more common and perhaps had a different relation to time since the index MI if more patients had undergone autopsy.

CONCLUSIONS

In patients with evidence of major cardiac dysfunction after MI, recurrent MI found at autopsy is common and has often not been clinically detected.

Diabetes, glucose level, and risk of sudden cardiac death

AIMS

The prevalence of diabetes mellitus in industrialized countries is rapidly increasing, and diabetes is suspected to carry a particular high risk for sudden cardiac death (SCD).

METHODS AND RESULTS

We conducted a population-based case-control study at Group Health Cooperative. Cases (n=2040) experienced out-of-hospital cardiac arrest due to heart disease between 1980 and 1994. Controls (n=3800) were a stratified random sample of enrollees. Diabetes status was classified into four exclusive groups: (i) no diabetes, (ii) borderline, (iii) diabetes without microvascular disease (retinopathy or proteinuria), and (iv) diabetes with microvascular disease. When compared with no diabetes, we observed progressively higher risk of SCD associated with borderline diabetes [Odds ratio (OR)=1.24 (0.98-1.57)], diabetes without microvascular disease [OR=1.73 (1.28-2.34)], and diabetes with microvascular disease [OR=2.66 (1.84-3.85)], after adjustment for potential confounders (P-value for trend <0.001). Higher glucose levels were also associated with the risk of SCD both in the absence and in the presence of microvascular disease. However, subjects with microvascular complications but with glucose level <7.7 mmol/L were not at significant increased risk of SCD.

CONCLUSION

These results emphasize the role of diabetes as a strong risk factor for SCD and outline the importance of glucose level at every stage of diabetes severity.

Coronary artery remodelling is related to plaque composition

OBJECTIVE

To assess the potential relation between plaque composition and vascular remodelling by using spectral analysis of intravascular ultrasound (IVUS) radiofrequency data.

METHODS AND RESULTS

41 coronary vessels with non-significant (< 50% diameter stenosis by angiography), < or = 20 mm, non-ostial lesions located in non-culprit vessels underwent IVUS interrogation. IVUS radiofrequency data obtained with a 30 MHz catheter, were analysed with IVUS virtual histology software. A remodelling index (RI) was calculated and divided into three groups. Lesions with RI > or = 1.05 were considered to have positive remodelling and lesions with RI < or = 0.95 were considered to have negative remodelling. Lesions with RI > or = 1.05 had a significantly larger lipid core than lesions with RI 0.96-1.04 and RI < or = 0.95 (22.1 (6.3) v 15.1 (7.6) v 6.6 (6.9), p < 0.0001). A positive correlation between lipid core and RI (r = 0.83, p < 0.0001) and an inverse correlation between fibrous tissue and RI (r = -0.45, p = 0.003) were also significant. All of the positively remodelled lesions were thin cap fibroatheroma or fibroatheromatous lesions, whereas negatively remodelled lesions had a more stable phenotype, with 64% having pathological intimal thickening, 29% being fibrocalcific lesions, and only 7% fibroatheromatous lesions (p < 0.0001).

CONCLUSIONS

In this study, in vivo plaque composition and morphology assessed by spectral analysis of IVUS radiofrequency data were related to coronary artery remodelling.

Endovascular needle injection of cholesteryl linoleate into the arterial wall produces complex vascular lesions identifiable by intravascular ultrasound: early development in a porcine model of vulnerable plaque

BACKGROUND

We attempted to create a pig model of complex arterial lesions through the percutaneous injection of cholesteryl linoleate into the vessel wall.

METHODS AND RESULTS

A total of 81 arterial segments (27 arteries) underwent percutaneous intramural injection of cholesteryl linoleate, in eight pigs. Intravascular ultrasound (IVUS) analysis and corresponding histology were obtained for analysis at 2 and 4 weeks after injection. Overall, 18 out of 27 (67%) of the injected arterial segments displayed lesions identifiable by IVUS as an eccentric echolucent zone present within the deeper layer of the lesion. Quantitative IVUS analysis demonstrated that these lesions were non-occlusive (36+/-8% area stenosis), eccentric (eccentricity index, 0.78+/-0.07) and located into positively remodeled vessels (remodeling index, 1.45+/-0.24). By histology, these lesions were eccentric and comprised less than a third of the vessel circumference. Medial thickening and a thickened intima containing lipid droplets and mononuclear cells were consistently found. The presence of lipids or local wall thickening seen by histology colocalized with the presence of echolucent structures seen by IVUS in 65% of the coronary segments and 70% of the iliac segments.

CONCLUSIONS

The intramural deposition of cholesteryl linoleate results in the development of complex, lipid-containing inflammatory lesions in less than 4 weeks. These lesions are already identifiable by IVUS at 2 weeks and colocalize with histologic findings. Further development of this model may allow the validation of technologies designed to detect and treat high-risk atherosclerotic lesions.

Heart-rate profile during exercise as a predictor of sudden death

BACKGROUND

Changes in heart rate during exercise and recovery from exercise are mediated by the balance between sympathetic and vagal activity. Since alterations in the neural control of cardiac function contribute to the risk of sudden death, we tested the hypothesis that among apparently healthy persons, sudden death is more likely to occur in the presence of abnormal heart-rate profiles during exercise and recovery.

METHODS

A total of 5713 asymptomatic working men (between the ages of 42 and 53 years), none of whom had clinically detectable cardiovascular disease, underwent standardized graded exercise testing between 1967 and 1972. We examined data on the subjects' resting heart rates, the increase in rate from the resting level to the peak exercise level, and the decrease in rate from the peak exercise level to the level one minute after the termination of exercise.

RESULTS

During a 23-year follow-up period, 81 subjects died suddenly. The risk of sudden death from myocardial infarction was increased in subjects with a resting heart rate that was more than 75 beats per minute (relative risk, 3.92; 95 percent confidence interval, 1.91 to 8.00); in subjects with an increase in heart rate during exercise that was less than 89 beats per minute (relative risk, 6.18; 95 percent confidence interval, 2.37 to 16.11); and in subjects with a decrease in heart rate of less than 25 beats per minute after the termination of exercise (relative risk, 2.20; 95 percent confidence interval, 1.02 to 4.74). After adjustment for potential confounding variables, these three factors remained strongly associated with an increased risk of sudden death, with a moderate but significantly increased risk of death from any cause but not of nonsudden death from myocardial infarction.

CONCLUSIONS

The heart-rate profile during exercise and recovery is a predictor of sudden death.

Cardiac positron emission tomography imaging

Cardiac positron emission tomography (PET) imaging has advanced from primarily a research tool to a practical, high-performance clinical imaging modality. The widespread availability of state-of-the-art PET gamma cameras, the commercial availability of perfusion and viability PET imaging tracers, reimbursement for PET perfusion and viability procedures by government and private health insurance plans, and the availability of computer software for image display of perfusion, wall motion, and viability images have all been a key to cardiac PET imaging becoming a routine clinical tool. Although myocardial perfusion PET imaging is an option for all patients requiring stress perfusion imaging, there are identifiable patient groups difficult to image with conventional single-photon emission computed tomography imaging that are particularly likely to benefit from PET imaging, such as obese patients, women, patients with previous nondiagnostic tests, and patients with poor left ventricular function attributable to coronary artery disease considered for revascularization. Myocardial PET perfusion imaging with rubidium-82 is noteworthy for high efficiency, rapid throughput, and in a high-volume setting, low operational costs. PET metabolic viability imaging continues to be a noninvasive standard for diagnosis of viability imaging. Cardiac PET imaging has been shown to be cost-effective. The potential of routine quantification of resting and stress blood flow and coronary flow reserve in response to pharmacologic and cold-pressor stress offers tantalizing possibilities of enhancing the power of PET myocardial perfusion imaging. This can be achieved by providing assurance of stress quality control, in enhancing diagnosis and risk stratification in patients with coronary artery disease, and expanding diagnostic imaging into the realm of detection of early coronary artery disease and endothelial dysfunction subject to risk factor modification. Combined PET and x-ray computed tomography imaging (PET-CT) results in enhanced patient throughput and efficiency. The combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. Evaluation of the clinical role of these creative new possibilities warrants investigation.

The pathogenesis of atherosclerosis

Worldwide, more people die of the complications of atherosclerosis than of any other cause. It is not surprising, therefore, that enormous resources have been devoted to studying the pathogenesis of this condition. This article attempts to summarize present knowledge on the events that take place within the arterial wall during atherogenesis. Classical risk factors are not dealt with as they are the subjects of other parts of this book. First, we deal with the role of endothelial dysfunction and infection in initiating the atherosclerotic lesion. Then we describe the development of the lesion itself, with particular emphasis on the cell types involved and the interactions between them. The next section of the chapter deals with the events leading to thrombotic occlusion of the atherosclerotic vessel, the cause of heart attack and stroke. Finally, we describe the advantages--and limitations--of current animal models as they contribute to our understanding of atherosclerosis and its complications.

Prognostic value of interleukin-6, plasma viscosity, fibrinogen, von Willebrand factor, tissue factor and vascular endothelial growth factor levels in congestive heart failure

BACKGROUND

Congestive heart failure (CHF) carries a poor prognosis with a high mortality rate, frequent hospitalizations and increased risk of thrombotic complications such as stroke. Cytokines may contribute to the progression and prothrombotic state of CHF, including the pro-inflammatory interleukin-6 (IL-6) and the pro-angiogenic vascular endothelial growth factor (VEGF), both of which are raised in CHF. The procoagulant properties of both cytokines may be mediated via tissue factor (TF), a potent clotting activator. We hypothesized that plasma levels of these markers, as well as levels of plasma viscosity, fibrinogen, soluble P-selectin and von Willebrand factor (markers of abnormal rheology, clotting, platelet activation, and endothelial damage, respectively) will be useful in predicting morbidity and mortality in chronic stable CHF.

METHODS AND RESULTS

One hundred and twenty consecutive out-patients with chronic stable CHF (92 males; mean [SD] age 64 [11] years, mean [SD] left ventricular ejection fraction of 29 [6]%) were recruited and followed for 2 years during which 42 patients reached a clinical end-point of all-cause mortality and cardiovascular hospitalizations, including stroke and myocardial infarction. Plasma IL-6 (P=0.003) and TF (P=0.013) levels, but not other research indices, were higher in those who suffered events compared with those without events. Predictors of end-points were high (> or =median) TF (P=0.011), and IL-6 (P=0.023) levels, as well as the lowest quartile of a left ventricular ejection fraction (P=0.007). A strong correlation was present between TF and IL-6 levels (r=0.59; P<0.0001) and with VEGF levels (r=0.43; P<0.0001).

CONCLUSION

IL-6 and TF are predictors of poor prognosis in chronic CHF, raising the hypothesis that IL-6 may contribute to the progression and thrombotic complications of CHF via its actions on TF expression. Although VEGF did not independently predict outcome in chronic CHF, the possibility arises that it may act with IL-6 to induce TF expression.

Interleukin-6, tissue factor and von Willebrand factor in acute decompensated heart failure: relationship to treatment and prognosis

Arterial thrombotic and thromboembolic complications are increased in congestive heart failure (CHF), and are a particular problem in acute decompensated heart failure, which carries a poor prognosis. As interleukin-6 (IL-6) has been shown to induce the potent procoagulant tissue factor (TF) in experimental models, we hypothesized that the pro-inflammatory IL-6 may be one mechanism contributing to thrombosis in heart failure, mediated via endothelial expression of TF on activated/damaged cells [indicated by plasma von Willebrand factor (vWF)]. Seventy-seven patients (67% men, New York Heart Association class III-IV, 87%) with acute CHF were recruited, and were compared with 53 chronic stable CHF patients in sinus rhythm (66% men, New York Heart Association class III-IV, 2%) and 37 healthy controls (68% men). Acute CHF patients in sinus rhythm had elevated baseline levels of IL-6 (P < 0.0001), TF (P = 0.041) and vWF (P < 0.0001) (all measured by enzyme-linked immunosorbent assay) compared with both chronic CHF and healthy control groups. A correlation exists in acute CHF between baseline TF and IL-6 (Spearman r = 0.64, P < 0.0001). After 3 months treatment, with control or alleviation of heart failure symptoms in 40 patients, there was a fall in levels of IL-6 (P < 0.0001) and vWF (P < 0.0001), but levels still remained significantly higher than healthy controls. Patients who died at 6 months follow-up also had higher baseline levels of IL-6 (P = 0.008), TF (P = 0.037) and vWF (P = 0.039) when compared with those who remained alive. Elevated IL-6 may contribute to the thrombotic and thromboembolic complications in acute heart failure, in a process mediated via increased TF and vWF. Improvement of symptoms and plasma markers after treatment of acute CHF and prediction of prognosis by the markers may be useful in the clinical setting.

Psychotropic drugs, cardiac arrhythmia, and sudden death

A variety of drugs targeted towards the central nervous system are associated with cardiac side effects, some of which are linked with reports of arrhythmia and sudden death. Some psychotropic drugs, particularly tricyclic antidepressants (TCAs) and antipsychotic agents, are correlated with iatrogenic prolongation of the QT interval of the electrocardiogram (ECG). In turn, this is associated with the arrhythmia (TdP). This review discusses the association between psychotropic agents, arrhythmia and sudden death and, focusing on TCAs and antipsychotics, considers their range of cellular actions on the heart; potentially pro-arrhythmic interactions between psychotropic and other medications are also considered. At the cellular level TCAs, such as imipramine and amitriptyline, and antipsychotics, such as thioridazine, are associated with inhibition of potassium channels encoded by In many cases this cellular action correlates with ECG changes and a risk of TdP. However, not all psychotropic agents that inhibit HERG at the cellular level are associated equally with QT prolongation in patients, and the potential for QT prolongation is not always equally correlated with TdP. Differences in risk between classes of psychotropic drugs, and between individual drugs within a class, may result from additional cellular effects of particular agents, which may influence the consequent effects of inhibition of repolarizing potassium current.

Plaque rupture and consequent thromboses probably do not cause acute coronary syndromes

The objective of this communication is to provide evidence that the spasm of resistance vessel (S-RV) concept of ischemic heart disease (IHD) and other ischemic disorders provides a more consistent set of explanations for acute coronary syndromes than the accepted mechanism of plaque rupture and consequent thromboses. The concept avers that S-RV directly induces symptoms in the various syndromes of IHD, including acute coronary syndromes. The S-RV concept is considered to be an alternate paradigm to explain IHD, and interest only develops in such models when there is significant doubt about the validity of the accepted paradigm. This report is an update of a study reported in this Journal in 1999 and has 2 changes; evidence will be evaluated by formal verification/falsification (pass/fail) methods - the method used to evaluate paradigms, and this report focuses on the mechanism of acute coronary syndromes because of the importance of these syndromes. It is well accepted that acute coronary syndromes are due directly to plaque rupture/thromboses, and there is considerable evidence to support this obvious mechanism. In spite of the obviousness of this mechanism, the S-RV concept asserts that S-RV is a more rational mechanism to explain acute coronary syndromes. Consistent with this position, the results of the study favor the S-RV concept. The standard position was given 8 passes, 2 passes with associated possible limited failures, and 2 possible failures. In contrast, the S-RV concept was given 12 passes, and no failures. Hopefully, the results of this study, and other available information about the S-RV concept, will prompt interest in the concept - such as independent testing of its premises.

Unheralded sudden cardiac death: do autonomic tone and thrombosis interact as key factors in aetiology?

Unheralded sudden cardiac death is a personal and family tragedy that continues to elude research-based progress on aetiology or prevention. Instinctive links between autonomic imbalance, sympathetic activation and serious arrhythmia are longstanding and backed by many observational reports. However the role of the more familiar mechanisms of coronary occlusion and thrombus formation are underplayed. Sympathetic overactivity may also mediate sudden death through precipitation of vasospasm; platelet activation and inhibition of endogenous fibrinolysis as well as the propagation of arrhythmia. The integration of autonomic, thrombotic and vascular tone may be the key to better understanding of the individual process of unheralded sudden cardiac death. In this review we analyse the evidence for this hypothesis.

Westernization of lifestyle markedly increases carotid intima-media wall thickness (IMT) in Japanese people

To illustrate the impact of westernization of lifestyle on the development of pre-clinical atherosclerosis in Japanese people, we compared risk factors for atherosclerosis such as serum lipids, blood pressure, BMI, insulin resistance, and smoking habits between non-diabetic native Japanese and non-diabetic Japanese Americans. Two hundred and twenty two non-diabetic Japanese Americans living in Hawaii and 271 non-diabetic Japanese living in Hiroshima, Japan were studied. Carotid intima-media wall thickness (IMT) was measured in all subjects by one physician. For all measurements the same ultrasound instrumentation was used. Although no significant differences were seen in serum total cholesterol (TC), triglycerides, or LDL-cholesterol (LDL-C) levels between the two groups in the 1998 study, previous to 1998 these three parameters were significantly higher in Japanese Americans than native Japanese in our study which has spanned the past 20 years. IMT was significantly greater in Japanese Americans than native Japanese (1.20+/-0.03 mm vs. 0.98+/-0.03 mm, (mean+/-S.E.) respectively; P<0.0001). Moreover Japanese Americans reach an IMT of 1.1 mm at age 50, whereas the native Japanese reach this value at age 70. These observations indicate more rapid atherosclerosis progression in Japanese Americans. Based on our IMT measurements, the status and the estimated progression of atherosclerosis in Japanese Americans is increased. Since IMT is a validated endpoint for assessment of atherosclerotic disease risk, it can be concluded that Japanese Americans are at increased risk for cardiovascular disease.

Morphologic and angiographic features of coronary plaque rupture detected by intravascular ultrasound

OBJECTIVES

This study was designed to report the clinical and angiographic correlates of plaque rupture detected by intravascular ultrasound (IVUS).

BACKGROUND

Acute coronary syndromes result from spontaneous plaque rupture and thrombosis.

METHODS

We report 300 plaque ruptures in 257 arteries in 254 patients. Plaque ruptures were detected during pre-intervention IVUS. Standard clinical, angiographic, and IVUS parameters were collected and/or measured. One lesion per patient was analyzed.

RESULTS

Multiple ruptures were observed in 39 of 254 patients (15%), 36 in the same artery. Plaque rupture occurred not only in patients with unstable angina (46%) or myocardial infarction (MI, 33%), but also stable angina (11%) or no symptoms (11%). The tear in the fibrous cap could be identified in 157 of 254 patients; 63% occurred at the shoulder of the plaque and 37% in the center of the plaque. Thrombi were more common in patients with unstable angina or MI (p = 0.02) and in multiple ruptures (p = 0.04). The plaque rupture site contained the minimum lumen area (MLA) site in only 28% of patients; rupture sites had larger arterial and lumen areas and more positive remodeling than MLA sites. Intravascular ultrasound plaque rupture strongly correlated with complex angiographic lesion morphology: ulceration in 81%, intimal flap in 40%, thrombus in 7%, and aneurysm in 7%.

CONCLUSIONS

Plaque ruptures occur with varying clinical presentations, strongly correlate with angiographic complex lesion morphology, may be multiple, and usually do not cause lumen compromise.

The epidemiology of out-of-hospital 'sudden' cardiac arrest

It is difficult to assemble data from an out-of-hospital cardiac arrest since there is often lack of objective information. The true incidence of sudden cardiac death out-of-hospital is not known since far from all of these patients are attended by emergency medical services. The incidence of out-of-hospital cardiac arrest increases with age and is more common among men. Among patients who die, the probability of having a fatal event outside hospital decreases with age; i. e. younger patients tend to more often die unexpectedly and outside hospital. Among the different initial arrhythmias, ventricular fibrillation is the most common among patients with cardiac aetiology. The true distribution of initial arrhythmias is not known since several minutes most often elapse between collapse and rhythm assessment. Most patients with out-of-hospital cardiac arrest have a cardiac aetiology. Out-of-hospital cardiac arrests most frequently occur in the patient's home, but the prognosis is shown to be better when they occur in a public place. Witnessed arrest, ventricular fibrillation as initial arrhythmia and cardiopulmonary resuscitation are important predictors for immediate survival. In the long-term perspective, cardiac arrest in connection with acute myocardial infarction, high left ventricular ejection fraction, moderate age, absence of other heart failure signs and no history of myocardial infarction promotes better prognosis. Still there is much to learn about time trends, the influence of patient characteristics, comorbidity and hospital treatment among patients with prehospital cardiac arrest.

Pathology of the unstable plaque

The term "vulnerable" in the context of human coronary plaques was originally intended to provide a morphological description consistent with lesions prone to rupture. Coronary thrombosis is now recognized as a diverse process arising from plaque rupture, erosion, or calcified nodules. These findings have prompted the search for more definitive terminology to describe the precursor lesion of rupture, now referred to as "thin-cap fibroatheromas." This review provides a focused discussion of the thin-cap fibroatheroma as a specific cause of acute coronary syndromes. The pathology of the unstable plaque is presented in reference to unstable angina, acute myocardial infarction, and sudden coronary death. The influence of risk factors for coronary artery disease on culprit lesion morphology is also discussed. Finally, the value of coronary calcification, as a predictor of unstable plaques in the clinical setting, is explored.

Pathological features of witnessed out-of-hospital cardiac arrest presenting with ventricular fibrillation

OBJECTIVES

To determine which characteristic pathological features are predictive of the presenting rhythm and survival in victims of community cardiac arrest.

DESIGN

Case-controlled retrospective autopsy study.

SETTING

County of Nottinghamshire with a total population of 993 914 and an area of 2183 square kilometers.

SUBJECTS

Between January 1, 1991 and December 31, 1994, 1535 witnessed cardiac arrests attended by the Nottinghamshire Ambulance Service, of which 1083 had an autopsy performed.

RESULTS

Ischaemic heart disease accounted for 72.3% of cases with a further 3.6% of deaths from other cardiac causes and the remainder from non-cardiac causes. Old healed myocardial infarction was present in 39.4%, and visible fresh occlusive thrombus was found in 23.8% of cases overall. Logistic regression analysis of deaths from cardiac causes revealed that younger age (odds ratio of 0.98 (95% CI 0.97-0.99)), two vessel coronary artery disease (odds ratio of 1.65 (95% CI 1.08-2.52)) and heart weight greater than 500 grams (odds ratio of 1.56 (95% CI 1.12-2.17)) were found to be independent predictors of developing ventricular fibrillation compared to other rhythms of arrest. Being male, visible occlusive thrombus and having survived a previous myocardial infarction were found not to be independent variables. There were no outstanding pathological features in the 31 patients who survived to hospital admission and subsequently died, compared with non-survivors who were considered to have died from a cardiac cause.

CONCLUSIONS

Among those who had a witnessed out-of-hospital cardiac arrest from a cardiac cause, increasing heart weight (the most likely cause of which is left ventricular hypertrophy), younger age and two vessel coronary artery disease appear to be much more important pathological features in the development of ventricular fibrillation than a previous myocardial infarction and fresh visible occlusive thrombus.

Long-term mortality among patients discharged alive after out-of-hospital cardiac arrest does not differ markedly compared with that of myocardial infarct patients without out-of-hospital cardiac arrest

The aim of our research was to study the long-term prognosis among patients discharged alive after an out-of-hospital cardiac arrest (OHCA) in comparison with patients discharged alive after acute myocardial infarction (AMI) without OHCA, and also to study the long-term influence of AMI in connection with OHCA. Our research was conducted in the municipality of Göteborg. We retrospectively studied patients discharged from hospital 1990-91 after an OHCA of cardiac aetiology and patients discharged after an AMI without prehospital cardiac arrest. During 1980-98, we studied all patients discharged alive after OHCA of cardiac aetiology, divided into groups of precipitating AMI and no AMI. The study includes 48 patients discharged alive after an OHCA 1990-91, 30 (62%) of whom had a simultaneous AMI and 1425 patients with an AMI without OHCA. Compared with AMI survivors, survivors of an OHCA of cardiac origin were younger but had more frequently a history of congestive heart failure. Their mortality rate during the subsequent 5 years was 46%, compared with 40% among survivors of an AMI (NS). The 5-year mortality rate among patients with an OHCA precipitated by an AMI was 40%. When correcting for differences at baseline, the adjusted risk ratio for death among patients with an OHCA of cardiac origin was 1.2 (95% CI 0.8-1.8) compared with patients with an uncomplicated AMI. During 1980-98, 215 patients were judged as having an OHCA precipitated by an AMI and 115 patients had an OHCA of cardiac aetiology but no simultaneous AMI. Five-year mortality was 54% and 50% respectively (NS). It is concluded that survivors of an OHCA of cardiac origin differed from survivors of an uncomplicated AMI in that they were younger and more frequently had a history of cardiovascular disease. Their 5-year mortality after discharge was similar to that of survivors of an AMI without a prehospital cardiac arrest, even after adjusting for differences at baseline.

To anticoagulate or not to anticoagulate patients with cardiomyopathy

The current published literature does not indicate whether the long-term effect of anticoagulant or antiplatelet therapy contributes to mortality reduction in patients with LV dysfunction. Evaluating patients for personal risk for emboli or for ischemic coronary artery events may influence the choice of therapies. As more is learned about the mechanisms of drug effects in different populations, physicians may be better able to direct appropriate therapies. Until that time, one must weigh the risks and benefits of each drug alone and in combination. In NYHA class IV patients, the risk for thrombosis owing to spontaneous clotting increases as does the adverse potential of warfarin and the adverse effects of inhibiting prostaglandin mediated vasodilation by aspirin. In NYHA class I and II patients, the quality of life and convenience of multidrug therapy is weighed against the devastating effect of a major stroke. In less symptomatic patients, the long-term risk for acute coronary events may be higher than previously identified. This would suggest that all patients with depressed LV function should be on some type of antiplatelet or anticoagulant therapy. The current WATCH study will provide much needed information about the outcome differences between these agents. Conclusions based on available data include the following: Heart failure is increasing in incidence and prevalence. Atherosclerotic disease is an important causative factor for the development of heart failure or may be a comorbid condition in these patients. There is a measurable rate of stroke in patients with heart failure, although the cause of death in large studies is more often owing to sudden death or progressive heart failure. Sudden death may be from new ischemic events, asystole, or from ventricular tachyarrhythmias. In patients with heart failure, not all strokes are cardioembolic in origin. The benefits and risks of warfarin may be increased as the EF worsens or heart failure functional class declines. The interactions of aspirin and ACE inhibitors have been best evaluated for the hemodynamic effects. There may be additional factors hitherto not studied. The hemodynamic effect of ACE inhibitors may be more important in NYHA classes III and IV than in less symptomatic patients. Warfarin use has clear indications for patients in atrial fibrillation with mechanical prosthetic valves, in hypercoagulable states, and with a previous history of embolization. Aspirin is inexpensive and commonly available, but its use must be evaluated and articulated by the prescribing physician. The current multicenter prospective trials will provide much needed guidance on this subject. The ongoing trials do not have a placebo arm, however, indicating a consensus among clinicians that patients with cardiomyopathy should be on an antiplatelet or anticoagulant drug until further data emerge.

The thin-cap fibroatheroma: a type of vulnerable plaque: the major precursor lesion to acute coronary syndromes

While the concept of plaque 'vulnerability' implies a propensity towards thrombosis, the term vulnerable was originally intended to provide a morphologic description consistent with plaques that are prone to rupture. It is now known that the etiology of coronary thrombi is diverse and can arise from entities of plaque erosion or calcified nodules. These findings have prompted the search for more definitive terminology to describe precursor lesions associated with rupture, now referred to as thin-cap fibroatheromas. This review focuses on the thin-cap fibroatheroma, as a specific cause of acute coronary syndromes. To put these issues into current perspective, we need to revisit some of the older literature describing plaque morphology in stable and unstable angina, acute myocardial infarction, and sudden coronary death. The morphology, frequency, and precise location of these thin-cap fibroatheromas are further discussed in detail. Potential mechanisms of fibrous cap thinning are also addressed, in particular emerging data, which suggests the role of cell death "apoptosis" in cap atrophy.

Sudden cardiac death

The rate of cardiac deaths that are sudden is approximately 50%, and decreases with age. The causes of sudden cardiac death are diverse, and are a function of age. In children and adolescents, coronary anomalies, hypertrophic cardiomyopathy and myocarditis are frequent substrates for lethal arrhythmias; in adults, coronary atherosclerosis and acquired forms of cardiomyopathy are the most common findings at autopsies of sudden cardiac death. This review focuses on coronary causes of sudden cardiac death, especially congenital coronary artery anomalies, which result in sudden death almost exclusively in adults younger than age 35, and coronary thrombosis. The most lethal coronary artery anomaly is the left coronary artery arising from the right sinus of Valsalva; this anomaly often results in fatal arrhythmias, often with exercise. The right coronary artery arising from the left sinus of Valsalva may also be lethal in adolescents and young adults, but, unlike the anomalous left, is more often an incidental finding at autopsy. Approximately 60% of sudden coronary death is caused by coronary thrombosis, the rest die with severe coronary disease in the absence of thrombosis. The two major substrates of coronary thrombosis are plaque rupture and plaque erosion, and are not only different pathologically, but are seen in patients with divergent risk factor profiles. Plaque rupture is the most common cause of fatal coronary thrombus, and is characterized by necrotic core with a thin fibrous cap, infiltrated by macrophages. The factors that result in plaque instability and rupture are largely unknown, and are under intense scrutiny; morphologic studies have identified serum lipid abnormalities as a key risk factor in the development of plaque rupture. Plaque erosion, in contrast to plaque rupture, is seen in younger men and women, is not associated with lipid abnormalities, and does not result from exposure of the lipid core to the lumen. The heterogeneity of the atherosclerotic plaque and the diverse mechanics of plaque progression and thrombosis have only been relatively recently explored, and are largely elucidated by autopsy studies of victims of sudden coronary death.

Coronary atherosclerosis in unheralded sudden coronary death under age 50: histo-pathologic comparison with 'healthy' subjects dying out of hospital

AIM

sudden coronary death (SCD) in older individuals is generally associated with extensive coronary atherosclerosis, although it may be the first manifestation of ischaemic heart disease. In younger age-groups, SCD may occur in the presence of less severe disease. We sought to (1) examine the extent of coronary atherosclerosis in young victims of SCD compared with age- and sex-matched controls, (2) analyse the composition of atherosclerotic plaques in these patients, (3) identify the predominant mechanism of SCD, and (4) evaluate the possibility of detecting this mechanism on the basis of morphologic plaque features, in particular presence and amount of lipid accumulation and calcific deposits.

METHODS AND RESULTS

coronary arteries were obtained at autopsy from 28 victims of SCD under age 50 with no prior clinical manifestation of ischaemic heart disease (IHD) and no myocardial scar formation and from 16 age- and sex-matched subjects dying of noncardiac causes out of hospital. Sections of all available major coronary arteries were cut in 5-mm intervals to yield a total of 1357 histologic sections, which were analysed using digitised planimetry. Victims of SCD had significantly more major coronary arteries per subject with luminal area narrowing > or = 75% than controls (on average, 2.1 vs. 0.2). Plaque area per histologic section was 5.1 +/- 2.1 mm(2) in SCD cases and 2.0 +/- 0.9 mm(2) in controls (P < 0.001). The major constituent of all plaques was fibrous tissue. Lipid core area per section was 0.49 +/- 0.59 mm(2) in SCD cases and 0.004 +/- 0.01 mm(2) in controls (P < 0.001), and calcified plaque area was 0.18 +/- 0.19 mm(2) in SCD cases and 0.02 +/- 0.05 mm(2) in controls (P < 0.001), both defining significant differences between SCD cases and controls. Arterial thrombosis, most often with underlying plaque rupture was the mechanism of SCD in > 80% of the cases. Considering histologic sections with > or = 50 and with > or = 75% area stenosis, plaque rupture was independently predicted by lipid core area. Calcific deposits were a frequent feature of plaque rupture but were only associated with it in univariate analysis.

CONCLUSIONS

the extent and severity of coronary atherosclerosis in young victims of SCD as the first manifestation of IHD was substantially greater than in age-and sex-matched controls and comparable with that previously reported in SCD cases with a broader age range. Lipid core and calcified plaque areas provided for excellent separation between the two groups, which may have implications for identifying persons at increased risk for SCD by non invasive visualisation and assessment of the coronary arteries.

New developments in the detection of vulnerable plaque

Failure of coronary angiography (luminography) in prediction of future acute coronary syndromes has cast a shadow of doubt over the value of this old gold-standard technique. The fact that angiographically invisible or nonsignificant lesions cause the majority of acute coronary syndromes has driven scientists to develop new diagnostic methods. In this article, we review the ongoing worldwide research on both invasive techniques (such as intravascular angioscopy and colorimetry, ultrasound, thermography, optical coherence tomography, near infrared spectroscopy, Raman spectroscopy, fluorescence emission spectroscopy, elastography, magnetic resonance imaging and spectroscopy, nuclear immunoscintigraphy, electrical impedance imaging, vascular tissue doppler, and shear stress imaging) and noninvasive techniques (such as MRI, contrast-enhanced MRI with and without immunolabeled agents, electron beam computed tomography, multi-slice spiral / helical computed tomography, and nuclear imaging, including positron emission tomography). Each of these techniques and their potential combination holds promise for characterization of plaques responsible for acute coronary syndromes, namely vulnerable plaque.

Effect of menopause on plaque morphologic characteristics in coronary atherosclerosis

BACKGROUND

Coronary artery disease in women appears 10 to 15 years later than in men. To test the hypothesis that the effects of estrogen may manifest themselves as histologic differences in coronary plaques, we examined the hearts of premenopausal and postmenopausal women who died suddenly from coronary artery disease.

METHODS

We studied 51 cases of sudden coronary death and 47 deaths in women who died from noncoronary causes. Coronary deaths were classified on the basis of histologic features. The number of acute plaque ruptures, healed plaque ruptures, vulnerable plaques, and acute plaque erosions were compared between groups. Postmortem values of serum total cholesterol, HDL cholesterol, and thiocyanate were measured, and menopausal status was confirmed by calculating body mass index.

RESULTS

Women older than 50 years of age were much more likely to have a ruptured plaque than were younger, premenopausal women. Plaque rupture was significantly associated with elevated total cholesterol level. In the 51 women who died of coronary disease, the mean number of vulnerable plaques increased significantly as women advanced into the postmenopausal years.

CONCLUSIONS

Our data suggest that estrogen has an anti-inflammatory effect on atherosclerotic plaques, resulting in plaque stabilization. Plaque erosion, the major substrate for thrombosis in premenopausal women, does not appear to be inhibited by estrogen. Because plaque progression may result both from repeated rupture and repeated erosion, a better understanding of the effect of estrogen on atherosclerosis may yield insights into the nature of coronary artery disease.

Therapeutic developments in sudden cardiac death

Sudden cardiac death is characterised by the unexpected death of a patient who has been clinically stable. It is frequently due to the development of ventricular tachyarrhythmias. With appropriate treatment, patients can be appropriately resuscitated. Clinically, it is essential to develop treatment strategies to prevent such an episode, as most patients do not survive out-of-hospital cardiac arrest. beta-Blockers are an effective pharmacological therapy in patients following myocardial infarction and in those with congestive heart failure. They may also be effective in other types of heart disease. Anti-arrhythmic agents are not useful as prophylactic drug therapy for reducing mortality in patients at risk for sudden cardiac death. Amiodarone is a notable exception, which may have some benefit, particularly in some subgroups. The implantable cardioverter-defibrillator has emerged as the most effective therapy for preventing sudden cardiac death in high-risk patients. Further work is required to enhance the characterisation of high-risk patients. Genetic analyses in patients with cardiovascular disorders may also identify new approaches to the prevention of sudden cardiac death.

Localization of apoptotic macrophages at the site of plaque rupture in sudden coronary death

Although apoptosis is a well-recognized phenomenon in chronic atherosclerotic disease, its role in sudden coronary death, in particular, acute plaque rupture is unknown. Culprit lesions from 40 cases of sudden coronary death were evaluated. Cases were divided into two mechanisms of death: ruptured plaques with acute thrombosis (n = 25) and stable plaques with and without healed myocardial infarction (n = 15). Apoptotic cells were identified by staining of fragmented DNA and confirmed in select cases by gold conjugate labeling combined with ultrastructural analysis. Additional studies were performed to examine the expression and activation of two inducers of apoptosis, caspases-1 and -3. Ruptured plaques showed extensive macrophage infiltration of the fibrous cap, in particular at rupture sites contrary to stable lesions, which contained fewer inflammatory cells. Among the culprit lesions, the overall incidence of apoptosis in fibrous caps was significantly greater in ruptured plaques (P < 0.001) and was predominantly localized to the CD68-positive macrophages. Furthermore, apoptosis at plaque rupture sites was more frequent than in areas of intact fibrous cap (P = 0. 028). Plaque rupture sites demonstrated a strong immunoreactivity to caspase-1 within the apoptotic macrophages; staining for caspase-3 was weak. Immunoblot analysis of ruptured plaques demonstrated caspase-1 up-regulation and the presence of its active p20 subunit whereas stable lesions showed only the precursor; nonatherosclerotic control segments were negative for both precursor and active enzyme. These findings demonstrate extensive apoptosis of macrophages limited to the site of plaque rupture. The proteolytic cleavage of caspase-1 in ruptured plaques suggests activation of this apoptotic precursor. Whether macrophage apoptosis is essential to acute plaque rupture or is a response to the rupture itself remains to be determined.

Occlusions of epicardial arteries might not directly induce symptoms in ischemic heart disease

It is accepted that primary occlusions of epicardial arteries by thromboses, stenotic coronary artery disease (CAD), and spasm directly induce symptoms in ischemic heart disease (IHD). Because of this acceptance, there has been little interest in alternate mechanisms for IHD--as the spasm of resistance vessel (S-RV) concept of IHD, which asserts that S-RV directly induces symptoms in IHD. To stimulate interest in the S-RV concept, evidence against the primacy of occlusions of epicardial arteries was presented, as well as evidence for this position to provide a balanced discussion; while the evidence was mixed, overall findings appeared to weigh significantly against the primacy of occlusions of epicardial arteries. Also, the S-RV concept was discussed; the discussion included presenting the theory's explanations for events in epicardial arteries, with the aim of demonstrating that the concept provides more consistent explanations than the standard position. It is suggested that there is sufficient information to warrant renewed consideration of the S-RV concept.

Changes in health status and quality of life and the impact of uncertainty in patients who survive life-threatening arrhythmias

OBJECTIVE

The purpose of this study was to describe the changes in perception of health status and quality of life from before treatment to 6 months after and the impact of uncertainty on these variables in survivors of life-threatening arrhythmia.

DESIGN AND SETTING

A descriptive correlational design at a large urban teaching hospital.

MEASURES

We measured health status, quality of life, and uncertainty before treatment and 6 months after a life-threatening arrhythmia.

RESULTS

Survivors included 66 men and 15 women, 41 of whom received pharmacologic therapy and 36 of whom received an implantable cardioverter defibrillator (ICD), completed the Medical Outcomes Survey (SF-36), Ferrans and Powers Quality of Life Index (QLI), and the Mishel Uncertainty in Illness Scale (MUIS-C) before treatment and 6 months after. There were significant improvements in the mental and physical health composite summaries as measured by the SF36 (P <.01). Conversely, there were significant reductions in the overall score and specifically in socioeconomic and psychological/spiritual quality of life domains as measured by the QLI (P <.05). An increased perception of uncertainty was related to decreased perception of health status and quality of life at both measurement times, with higher correlations 6 months later.

CONCLUSIONS

Survivors demonstrated improvements in perceived health status, although this did not appear to translate into improvements in the subjective domains of quality of life. The overall quality of life and the domains of psychological/spiritual state and socioeconomic status were lower 6 months after a life-threatening arrhythmia. Uncertainty had a significant impact on these perceptions, identifying an area for nursing interventions.