Metaiodobenzylguanidine and heart rate variability in heart failure

It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF.     

An activator/repressor dual system allows tight tetracycline-regulated gene expression in budding yeast

OBJECTIVES: This study sought to determine the prevalence and significance of nonsustained ventricular tachycardia (NSVT) in patients with premature ventricular contractions (PVCs) and heart failure treated with vasodilator therapy. BACKGROUND: Heart failure patients with ventricular arrhythmia and NSVT have a significantly increased risk of premature cardiac death. Recently there has been the question of whether these arrhythmias are expressions of a severely compromised ventricle or are they independent risk factors. We, therefore, determined the prevalence and significance of NSVT in patients with PVCs and heart failure and on vasodilator therapy. METHODS: Twenty-four hour ambulatory recordings were done at randomization, at 2 weeks, at months 1, 3, 6, 9 and 12 and then every 6 months in 674 patients with heart failure and on vasodilator therapy. The median period of follow-up was 45 months (range 0 to 54). RESULTS: Nonsustained ventricular tachycardia was present in 80% of all patients. Patients without (group 1) and with (group 2) NSVT were balanced for variables: age, etiology of heart disease, New York Heart Association (NYHA) functional class, use of amiodarone and diuretics and left ventricular diameter by echocardiogram. However, group 1 patients had significantly less beta-adrenergic blocking agent use and higher ejection fraction (EF) (p < 0.002 and p < 0.001, respectively). Survival analysis for all deaths showed a greater risk of death among group 2 patients (p=0.01). Similarly, sudden death was increased in group 2 patients (p=0.02, risk ratio 1.8). After adjusting for the above variables, only EF (p=0.001) and NYHA class (p=0.01) were shown to be independent predictors of survival. Nonsustained ventricular tachycardia showed a trend (p=0.07) as an independent predictor for all-cause mortality but not for sudden death. Only EF was an independent predictor for sudden death. CONCLUSIONS: Nonsustained ventricular tachycardia is frequently seen in patients with heart failure and may be associated with worsened survival by univariate analysis. However, after adjusting other variables, especially for EF, NSVT was not an independent predictor of all-cause mortality or sudden death. These results have serious implications in that suppression of these arrhythmias may not improve survival.     

A case of hypertensive hypertrophy in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were observed after antihypertensive therapy

A case of hypertensive hypertrophy is described in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were seen after 7 months of antihypertensive therapy. A 58-year-old man was diagnosed as having essential hypertension and hypertensive hypertrophy. The patient was treated with antihypertensive drugs and showed regression of left ventricular hypertrophy on electrocardiograms and echocardiograms. MIBG observations made before and after antihypertensive therapy showed increased heart-to-mediastinum activity ratio and decreased cardiac washout ratio. Despite the many theories addressing the mechanisms of regression of left ventricular hypertrophy, the process is still unclear. In the present case, the improvement of cardiac sympathetic nervous dysfunction might have been related to the regression of left ventricular hypertrophy because the abnormality in MIBG images improved. MIBG, therefore, may be helpful in clarifying the mechanisms of the regression of hypertensive hypertrophy.     

Renaissance of beta blocker therapy in myocardial infarct

Beta-adrenergic blocking drugs have been evaluated for the treatment of arrhythmias and for the prevention of sudden cardia death, particularly in post-myocardial infarction patients. Betablockers have been demonstrated to reduce mortality, reinfarction, ventricular fibrillation and cardiac rupture in acute infarction. Therefore, in patients with suspected myocardial infarction and without contraindications, treatment with betablockers should be initiated early and continued for at least 2 years. Side-effects are mild and occur in approximately 10% of patients. Patients who have contraindications for betablockers use early in myocardial infarction should be reevaluated before discharge from the hospital and considered for such therapy. Because betablockers prevent some of the adverse arrhythmogenic mechanisms seen in chronic heart failure, it may be reasonable to expect that these drugs could have a role in preventing sudden cardiac death in these patients. Analysis of some of the betablocker post-infarction trials indicate that betablockers reduced the risk of sudden death in patients with heart failure at baseline. Some studies demonstrated also the symptomatic improvement following therapy with betablockers in patients with heart failure. But the currently available data are too limited to provide conclusive information.     

Heterogeneous sympathetic innervation in German shepherd dogs with inherited ventricular arrhythmia and sudden cardiac death

BACKGROUND: Recently, a colony of German shepherd dogs with inherited spontaneous cardiac arrhythmias and associated sudden death has been developed and characterized. Due to the median age of onset of the arrhythmia (4.5 months), the tendency for the arrhythmia to occur during REM sleep or after exercise, and the absence of structural heart disease, we hypothesized a developmental abnormality of the sympathetic innervation to the heart. METHODS AND RESULTS: We studied 11 dogs from this colony, ranging in age from 6 months to 6 years, and four 7-month-old German shepherd dogs unrelated to the colony as controls. We imaged the distribution of functional myocardial sympathetic innervation and perfusion with [123I]metaiodobenzylguanidine (MIBG) and 201Tl, respectively. Sympathetic nerve distribution was evaluated morphologically by immunocytochemical localization of tyrosine hydroxylase. All of the hearts showed evidence of a regional decrease in MIBG uptake, ranging from 5.3% to 53.4% of the myocardium, whereas control dogs showed homogeneous MIBG uptake. Immunocytochemical studies on sections from regions with decreased MIBG uptake showed a striking paucity of nerves compared with regions with normal MIBG uptake, confirming denervation. When the dogs were grouped into those with (n=6) and without (n=5) evidence of ventricular tachycardia on ambulatory ECG, the group with ventricular tachycardia showed 35+/-16.5% denervation, whereas the group without ventricular tachycardia showed 12+/-5.6% denervation (P<.02). CONCLUSIONS: Abnormal heterogeneous sympathetic innervation exists in these dogs with inherited ventricular arrhythmia and sudden cardiac death. Mechanisms relating the presence and extent of regional denervation to the incidence of ventricular arrhythmia remain to be defined.     

Direct evidence of impaired cardiac sympathetic innervation in essential hypertensive patients with left ventricular hypertrophy

Increased sympathetic nervous activity has been proposed as one of the causes of left ventricular hypertrophy (LVH) associated with hypertension. However, the precise relationship is not fully understood. METHODS: To elucidate the relationship between myocardial sympathetic nervous activity and LVH in patients with essential hypertension EHT), we performed 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 49 patients with EHT and 17 normotensive control subjects. Sympathetic innervation of the left ventricle was evaluated using SPECT, and the whole heart uptake of the tracer was quantitatively assessed as the heart-to-mediastinum uptake ratio on both the early (15-min) and delayed (5-hr) images. Myocardial washout rate (MWR) of the tracer from 15 min to 5 hr after the isotope administration was also calculated. The left ventricular mass index (LVMI) was determined echocardiographically. RESULTS: In 49 hypertensive patients, there was a negative correlation between LVMI and heart-to-mediastinum uptake ratio on both the early and delayed images (r=-0.55, p < 0.0001; r=-0.63, p < 0.0001, respectively). In addition, there was a positive correlation between the LVMI and MWR of 123I-MIBG in these hypertensive patients (r=0.59, p < 0.0001). As for the regional uptake of the tracer, there was no significant difference between control subjects and hypertensive patients without cardiac hypertrophy, but a significant decrease of the uptake in the inferior and lateral regions was observed in hypertensive patients with cardiac hypertrophy. CONCLUSION: Patients with EHT had decreased accumulation and increased MWR of 123I-MIBG in proportion to the degree of LVH. Hypertensive patients with cardiac hypertrophy had impaired sympathetic innervation in the inferior and lateral regions of the left ventricle.     

Substance P and related peptides in porcine cortex: whole tissue and nuclear localization

We experienced a case of a 60 year-old man with cardiac sympathetic denervation after aortic graft replacement of ascending aorta for a dissecting aneurysm (Debakey type II). Fourteen years after pheochromocytomectomy (paraganglioma), the patient developed a severe chest pain, and admitted to the hospital for the diagnosis of dissecting aneurysm. CT scan with contrast enhancement revealed thrombosed dissecting aneurysm in the region of ascending aorta to aortic arch. Graft replacement was undergone on the same day. 123I-MIBG imaging 20 days after the operation showed severely attenuated myocardial uptake (heart to mediastinum ratio 1.19), although the MIBG imaging before the operation showed normal myocardial uptake (heart to mediastinum ratio 1.55). Heart rate variability analysis in Holter ECG showed that the power of the low frequency (LF), that of the high frequency (HF) and L/H ratio were severely decreased. MIBG and heart rate variability analysis indicated that cardiac sympathetic and parasympathetic nerve were denervated. This is the first report of cardiac sympathetic denervation after aortic vascular surgery. Clinical significance of cardiac sympathetic denervation after aortic vascular surgery is uncertain, and further investigation will be required.     

The effect of the mean platelet volume on the short-term prognosis of acute myocardial infarct

INTRODUCTION AND OBJECTIVES: The increase of mean platelet volume in the late phase of myocardial infarction is an independent predictor for recurrent myocardial infarction and death, but the association between this finding and the short-term prognosis after acute myocardial infarction is unknown. The goals of this study were to assess the influence of mean platelet volume on the risk of death, recurrent ischemic events or cardiac heart failure during the in-hospital phase of myocardial infarction and to analyse the relationship between mean platelet volume and several demographic and clinical variables registered on admission. MATERIAL AND METHODS: A population of 1,082 patients with acute myocardial infarction were distributed in two groups according to the platelet volume measured on admission: group 1, mean platelet volume > 9 fl (n = 443) and group 2, mean platelet volume < or = 9 fl (n = 639). The difference between both groups on the end-point of this study were assessed by univariate and multivariate statistical methods. An univariate analysis was also applied to assess the relationship between platelet volume and the baseline variables. RESULTS: A mean platelet volume > 9 fl was associated with a significant increase of risk for the combined end-point considered (OR = 1.37; p = 0.026). By univariate analysis, an increased platelet volume was related to a higher risk of cardiac failure (OR = 1.46; p = 0.01) and a non-significant increase in the incidence of recurrent ischemic events (OR = 1.35; p = 0.07). In addition, a large platelet volume was also associated with a higher prevalence of prior myocardial infarction, arterial hypertension and diabetes mellitus. CONCLUSIONS: The results of this study suggest that the increase of mean platelet volume on admission is an independent risk factor for cardiac heart failure and is associated with a non significant higher rates of ischemic events during the recovery phase of acute myocardial infarction.     

Antiarrhythmic therapies for the prevention of sudden cardiac death

Despite remarkable advances in cardiovascular therapeutics, sudden cardiac death remains a significant problem. In this review, data from clinical trials and other studies on antiarrhythmic therapies have been evaluated in order to determine effective strategies for the prevention of sudden cardiac death in high risk patients. Overall, routine prophylactic use of class I antiarrhythmic agents in high risk patients, mostly survivors of acute myocardial infarction, is associated with increased risk of death [61 trials, 23,486 patients: odds ratio (OR) 1.13; 95% confidence interval (CI) 1.01 to 1.27, p < 0.05]. Conversely, beta-blockers are associated with highly significant reductions in risk of death in postinfarction patients (56 trials, 53,521 patients: OR 0.81; 95% CI 0.75 to 0.87, p < 0.00001). Overall data from the amiodarone trials on high risk patients, including postinfarction patients, patients with congestive heart failure or survivors of cardiac arrest, suggest that this agent is effective in reducing the risk of death (14 trials, 5713 patients: OR 0.83; 95% CI 0.72 to 0.95, p = 0.01) although further studies are needed to better define which types of patients will potentially benefit most from this agent. No benefits were seen with calcium channel blockers (26 trials, 21,644 patients: OR 1.03; 95% CI 0.94 to 1.13, p = NS). The implantable cardioverter-defibrillator is a promising option for high risk patients, but definition of its role awaits the completion of ongoing clinical trials. Since causes of sudden death are heterogeneous, the clinician should pursue a multifactorial approach to its prevention. Primary and secondary prevention of cardiac ischaemia, through the treatment of cardiovascular risk factors and maximising the use of aspirin, beta-blockers, lipid-lowering drugs, and angiotensin converting enzyme inhibitors after acute myocardial infarction, should lead to a future decrease in the incidence of sudden cardiac death.     

Managed care and outcomes of hospitalization among elderly patients with congestive heart failure

123I-radiolabeled metaiodobenzylguanidine (123I-MIBG) cardiac imaging has been used to evaluate the distribution of sympathetic nervous system (SNS) in the heart. Different heart diseases have shown impaired cardiac SNS distribution as reflected by MIBG activity. The aim of this study was to assess the cardiac distribution of SNS in normal subjects, using MIBG imaging. Ten normal subjects (1 male and 9 females, mean age 46 +/- 9 years) with no cardiac abnormalities underwent myocardial 123I-MIBG scintigraphy, Tc-99m methoxyisobutylisonitrile (MIBI) cardiac perfusion imaging and equilibrium radionuclide angiography (RNA). Regional myocardial MIBG and MIBI activities were quantitatively evaluated using a region of interest analysis. For this purpose, the left ventricle was divided into 6 myocardial regions as anterior, apical, inferior, septum, lateral and posterolateral. In particular, myocardial MIBG and MIBI activities were measured as myocardium to mediastinum ratio. Regional left ventricular function was assessed by RNA. Myocardial MIBG uptake was homogeneous in anterior (2.2 +/- 0.5), inferior (2.5 +/- 0.7), septal (2.4 +/- 0.4), lateral (2.3 +/- 0.4), and posterolateral (2.3 +/- 0.4) regions. Conversely, MIBG uptake was significantly lower in the apical region (1.9 +/- 0.3) compared to all other left ventricular segments (p < 0.05). Regional myocardial perfusion, as measured by MIBI uptake, was homogeneous in all regions. No regional left ventricular wall motion abnormalities were observed by RNA. In conclusion, our data suggest that a decreased MIBG uptake may be observed in the left ventricular apical region of normal subjects reflecting reduced sympathetic innervation of the apex. This finding is not related to myocardial perfusion or wall motion abnormalities. The knowledge of cardiac sympathetic innervation in normal subjects may be helpful to assess SNS abnormalities in heart disease.     

Differences in prediction of mortality and non-fatal complications after acute myocardial infarction: a multivariate analysis

The global prognostic after acute myocardial infarction depends of the left ventricular function and the residual ischemia. However, there is controversy about the capacity of some variables reflecting this prognostic factors to predict futures complications. The main objective of this study is to know the influence of the kind of complications in the prognostic value of the variables more frequently used in the clinical practice. We studied 121 consecutive patients with acute myocardial infarction discharged from hospital. The previous and during acute infarction clinical variables were analyzed. The regional and global left ventricular function was studied by 2D echocardiography. An exercise test symptoms-limited was performed at 3rd week after discharge in 94 patients selected. The patients were followed during selected one year. The first year cardiac mortality rate was 8.6%. In the multivariate, the independent predictors of mortality were: age > 60 years (p = 0.02) and the impossibility to perform exercise test (p = 0.0002). In the univariate analysis the echocardiographic motility score > or = 17, eyection fraction < 35% and Killip class > or = II were also death predictors. Non fatal complications (angina, reinfarction o heart failure) were present in 47 patients (42.3%) of 111 survivors. The ischemic complications were predicted in multivariate analysis only by postinfarction angina (p = 0.0007), and heart failure by eyection fraction < 35% (p = 0.006), previous infarct (p = 0.002) and Killip class (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cervical intraepithelial neoplasia in adolescents: study of cytological findings between 1987 and 1995 in S?o Paulo State-Brazil

Cardiovascular complications are the most common causes of morbidity and mortality in diabetic patients. Coronary atherosclerosis is enhanced in diabetics, whereas myocardial infarction represents 20% of deaths of diabetic subjects. Furthermore, re-infarction and heart failure are more common in the diabetics. Diabetic cardiomyopathy is characterized by an early diastolic dysfunction and a later systolic one, with intracellular retention of calcium and sodium and loss of potassium. In addition, diabetes mellitus accelerates the development of left ventricular hypertrophy in hypertensive patients and increases cardiovascular mortality and morbidity. Treating the cardiovascular problems in diabetics must be undertaken with caution. Special consideration must be given with respect to the ionic and metabolic changes associated with diabetes. For example, although ACE inhibitors and calcium channel blockers are suitable agents, potassium channel openers cause myocardial preconditioning and decrease the infarct size in animal models, but they inhibit the insulin release after glucose administration in healthy subjects. Furthermore, potassium channel blockers abolish myocardial preconditioning and increase infarct size in animal models, but they protect the heart from the fatal arrhythmias induced by ischemia and reperfusion which may be important in diabetes. For example, diabetic peripheral neuropathy usually presents with silent ischemia and infarction. Mechanistically, parasympathetic cardiac nerve dysfunction, expressed as increased resting heart rate and decreased respiratory variation in heart rate, is more frequent than the sympathetic cardiac nerve dysfunction expressed as a decrease in the heart rate rise during standing.     

Sudden cardiac death: a retrospective and prospective study

Since the inception of mobile coronary care units (MCCU), patients with sudden cardiac death (SCD) saved by advanced emergency medical technicians (EMT-A) can be studied retrospectively and prospectively. Forty-eight cases of SCD found in ventricular fibrillation (VF) were successfully resuscitated. Only 32% had a myocardial infarction. Most survivors were New York Heart Association (NYHA) class I or II. All class IV survivors with severe congestive heart failure died within 45 days. All class II survivors had angina as the limiting factor. Of all patients with VF, 23% survived. Eighty percent of survivors were class I or II and have resumed previous lifestyles. No clear cut symptom complex was identified. Rescue response time was generally less than five minutes. Intracardiac medications were administered without complications. Empirical administration of sodium bicarbonate correlated poorly with arterial blood gas determinations.     

The stratification and prevention of the arrhythmia risk in nonischemic dilated cardiomyopathy]

The challenge of preventing arrhythmic sudden death is one of the major issues in today's treatment of heart failure. To achieve this ambitious goal, an accurate selection of the candidates for sudden death is needed on the one hand, while on the other hand, the assessment of the real cost/benefit ratio of the implantable cardioverter-defibrillator in selected patients, as compared to ACE inhibitors, beta-blockers and antiarrhythmic drug therapy, should no longer be delayed. As is well known, the incidence of sudden death is higher in ischemic dilated cardiomyopathy than it is in non-ischemic dilated cardiomyopathy. Moreover, tachyarrhythmic sudden death is prevalent in NYHA classes I and II (80%), whereas its incidence is lower (50%) in NYHA classes III and IV, since bradyarrhythmia, electromechanical dissociation and thromboembolic events characterize the other 50% of sudden deaths in patients in the latter NYHA class. The stratification of arrhythmic risk in non-ischemic dilated cardiomyopathy is questionable from any point of view, considering the poor predictive power of invasive and non-invasive indexes. However, some subgroups of high-risk patients should be selected, such as patients waiting for heart transplant or those with a severe disease but without an extreme degree of ventricular dysfunction, in whom the prognosis in terms of pump failure events is better and life expectancy is longer if the risk of arrhythmia is properly assessed and sudden death prevented. Consequently, the ICD implant may be effective in order to pursue the aim of reducing the tachyarrhythmic and bradyarrhythmic mortality in patients with a more severe disease and of minimizing the tachyarrhythmic risk in those with a less severe disease. Further studies will be developed to identify the ideal candidates for ICD implants.     

Undergraduate and postgraduate clinical education in Kobe University School of Medicine

A total of 4,849 male participants of the prospective cardiovascular Münster Study (PROCAM), aged 40 - 65 years underwent extensive screening for cardiovascular risk factors before 1986 and were subsequently followed up for at least 8 years. During this time 189 non-fatal and 49 fatal myocardial infarctions occurred, 28 men suffered a sudden cardiac death and 169 persons died of other causes. Using multivariate statistical methods we confirmed that age, increased LDL cholesterol levels, decreased HDL cholesterol levels, high blood pressure, cigarette smoking, diabetes mellitus, angina pectoris and a positive family history are important risk factors for a myocardial infarction or cardiac death. The results of the PROCAM Study demonstrate that elevated triglycerides are an independent risk factor for an early myocardial infarction or cardiac death. Using a multiple logistic function analysis an algorithm for the assessment of the global risk was derived from the data. The observed incidence of coronary heart disease rises sharply as the global risk increases, thus permitting the use of this algorithm in clinical practice for the assessment of the individual risk of myocardial infarction. Risk factors such as lipoprotein(a) and coagulation factors may improve the predictive value of this algorithm. Furthermore it is expected that the exploration of genetic defects will strongly increase the predictive value and precise determination of individual risk.     

Distinction between arrhythmic and nonarrhythmic death after acute myocardial infarction based on heart rate variability, signal-averaged electrocardiogram, ventricular arrhythmias and left ventricular ejection fraction

OBJECTIVES: We investigated whether heart rate variability, the signal-averaged electrocardiogram (ECG), ventricular arrhythmias and left ventricular ejection fraction predict the mechanism of cardiac death after myocardial infarction. BACKGROUND: Postinfarction risk stratification studies have almost exclusively focused on predicting the risk of arrhythmic death. The factors that identify and distinguish persons at risk for arrhythmic and nonarrhythmic death are poorly known. METHODS: Heart rate variability, the signal-averaged ECG, ventricular arrhythmias and left ventricular ejection fraction were assessed in 575 survivors of acute myocardial infarction. The patients were followed up for 2 years; arrhythmic and nonarrhythmic cardiac deaths were used as clinical end points. During the follow-up period, 47 cardiac deaths occurred, 29 (62%) arrhythmic and 18 (38%) nonarrhythmic. RESULTS: All risk factors were associated with cardiac mortality in univariate analysis. With the exception of left ventricular ejection fraction, they were also predictors of arrhythmic death. Depressed heart rate variability (p < 0.001), ventricular ectopic beats (p < 0.001) and low ejection fraction (p < 0.001) were related to nonarrhythmic death. In multivariate analysis, depressed heart rate variability (p < 0.001) and runs of ventricular tachycardia (p < 0.05) predicted arrhythmic death. Nonarrhythmic death was associated with depressed heart rate variability (p < 0.001), ventricular ectopic beats (p < 0.001) and low ejection fraction (p < 0.01). By selecting patients with depressed heart rate variability, long filtered QRS duration or ventricular arrhythmias and excluding patients with the lowest ejection fraction, we identified a group in which 75% of deaths were arrhythmic. Similarly, by selecting patients with a low ejection fraction and excluding patients with the lowest heart rate variability, we identified a group in which 75% of deaths were nonarrhythmic. CONCLUSIONS: Arrhythmic death was associated predominantly with depressed heart rate variability and ventricular tachycardia runs, and nonarrhythmic death with low ejection fraction, ventricular ectopic beats and depressed heart rate variability. A combination of risk factors identified patient groups in which a majority of deaths were either arrhythmic or nonarrhythmic.     

Sudden death among 1,000 patients with myocardial infarction: incidence and contributory factors. KYSMI Study Group

Clinical indicators and the incidence of sudden death among 1,000 consecutive patients (816 males and 184 females) with myocardial infarction were investigated between 1983 and 1987 after coronary arteriography. Twenty-four patients died suddenly during a study period of 3.3 +/- 2.0 yrs. The yearly incidence of sudden death calculated by the Kaplan-Meier method was 0.7%, nearly half of the incidence of cardiac death (1.5%/yr). Univariate analysis demonstrated statistically significant differences in the number of cases with coronary thrombolysis in the acute phase, degree of coronary artery stenosis, the frequency and degree of congestive heart failure and angina in the acute and chronic phase, the presence of serious post-infarction arrhythmia, ejection fraction, recurrent myocardial infarction, and administration of digitalis and diuretics. between the sudden-death group and the cardiac and other patient groups. There was also a tendency to higher frequency of history of diabetes mellitus, presence of acute mitral regurgitation, nitrates and nicorandil treatment, and coronary artery bypass graft in the sudden-death group. Multivariate analysis revealed that digitalis and nitrates treatment and left anterior descending artery involvement were major contributing factors. Re-infarction, left ventricular ejection fraction, and nicorandil therapy were not significant and minor contributing factors. The incidence of sudden death increased with digitalis therapy (Odds' ratio of 9.59), and left anterior descending artery disease, and decreased with nitrates (0.34).     

Pathogenesis of acute coronary syndromes

Coronary artery diseases may categorized into asymptomatic disease, angina pectoris, myocardial infarction, chronic heart failure, and sudden coronary death. Unstable angina, acute myocardial infarction, and sudden cardiac death are known as the acute coronary syndromes. Coronary atheroma is unstable in the patients with acute coronary syndromes. Stable plaques will be unstable when dynamic alterations occur. The alterations are plaque rupture, plaque hemorrhage, coronary thrombosis and vasospasm. They act each other. We analysed the histopathology of coronary arteries who died of acute myocardial infarction in 85 cases. It showed that the risk factors of plaque rupture are clusters of form cells, eccentric plaque with soft lipid rich core, and thinning of fibrous cap in atheroma. Most of these cases ruptured at edge of the atheroma.     

Vasoactive intestinal peptide and epidermal growth factor: co-mitogens or inhibitors of keratinocyte proliferation in vitro?

Adenosine myocardial perfusion single-photon emission computed tomography (SPECT) is now increasingly used for risk stratification of patients with known or suspected coronary artery disease. However, the incremental prognostic value of this test over clinical and historical information in a large series of women has not been examined. Thus, we studied 923 consecutive women who underwent adenosine technetium (Tc)-99m sestamibi myocardial perfusion SPECT and were followed-up for a mean period of 26+/-8 months. During the follow-up period, 77 hard events (46 cardiac deaths and 31 nonfatal myocardial infarctions) occurred. The results of the perfusion scan significantly risk stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (< 1%/year of follow up). Patients with mildly abnormal scans had low cardiac death rates (0.9%/year of follow up); these rates increased as a function of scan abnormality (4.1% and 7.5% mortality per year of follow up in moderate and severely abnormal scans). Cox proportional hazards analysis demonstrated that after adjusting for prior myocardial infarction and diabetes mellitus (the most predictive individual clinical variables [global chi-square=22.5, p <0.001]), as well as heart rate at rest (the most predictive physiologic variable [chi-square=3.8; p=0.05]), the most predictive nuclear variable (summed stress score [chi-square=48.5; p <0.0001]) added significant incremental prognostic information (global chi-square increased from 22.5 to 56.2 [p <0.0001]). In conclusion, adenosine myocardial perfusion SPECT added significant incremental prognostic information to clinical and physiologic variables in women. Normal scans were associated with an excellent prognosis. In contrast, patients with moderately to severely abnormal scans were at a higher risk for future cardiac events.     

Cardiac operations in the elderly: who is at risk?

BACKGROUND: With the growing number of elderly patients presenting for cardiac operations we analyzed their early survival data to determine whether any preoperative variables might be indicative of increased risk. METHODS: From 1990 to 1995, 436 consecutive patients who were 75 years old or older had either coronary artery bypass, valve replacement(s), or a combination of these. A total of 34 preoperative variables were assessed for their effect on hospital survival by using univariate and multivariable analysis. RESULTS: There were 266 men and 170 women, with 292 patients being 75 to 80 years old and 144 patients being older than 80 years. Coronary artery bypass was performed in 242 patients, valve replacement was performed in 93 patients, and a combination of these in 101 patients. The operation was considered elective in 202 patients, urgent in 209, and emergent in 25 patients of whom 21 were in cardiogenic shock. Overall there were 61 hospital deaths (13.9%). The most common cause of death, low cardiac output syndrome, occurred in 34 patients of whom 26 suffered a perioperative myocardial infarction. Stroke was the cause of death in eight and multiple organ failure accounted for nine deaths. In the univariate analysis, variables that influenced survival included heart failure (p = 0.004), pulmonary edema (p = 0.004), cardiomegaly (p = 0.02), elevated serum creatinine (p = 0.009), surgical priority (p = 0.002), and cardiogenic shock (p = 0.002). In the multivariable analysis there were three independent determinants of hospital survival: cardiomegaly (odds ratio, 1.8:1) serum creatinine level higher than 150 micromol/L (odds ratio, 5.5:1) and emergency procedure (odds ratio, 2.5:1). CONCLUSIONS: Although cardiac operations can be performed safely in many elderly patients, we identified several factors that might help both in case selection and in perioperative decisions.