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PubMed1996

Stepwise strategy of using short- and long-term heart rate variability for risk stratification after myocardial infarction.

Independent of other established risk factors, depressed heart rate variability (HRV) has been shown to be a powerful predictor of cardiac events after MI. Unfortunately, the need of 24-hour ECG recording and subsequent laborious editing of Holter data limits the clinical use of long-term HRV. In order to perform post-MI risk stratification more efficiently, we evaluated the value of short-term HRV estimates for preselection of patients who might benefit from long-term HRV assessment. Two measures were assessed from 24-hour ambulatory ECGs recorded in 729 survivors of acute MI prior to hospital discharge. In addition to a complete 24-hour HRV index, a standard deviation of normal-to-normal RR intervals (SDNN) was obtained from the first stationary and ectopic free 5-minute segment of the Holter recording. Predictive power (relation between positive predictive accuracy and sensitivity) of a complete 24-hour HRV index in identifying patients who suffered from cardiac mortality or arrhythmic events during a 2-year follow-up was compared to the predictive power of assessing the 24-hour HRV index limited to 50%, 40%, or 20% of patients with the lowest values of 5-minute SDNN. The HRV index was significantly lower in patients who died (19 +/- 11 units) or had an arrhythmic event (AE) (18 +/- 11 units) compared to those who survived without an event (28 +/- 10 resp. 27 +/- 11 units; P < 0.001). Similarly, 5-minute SDNN was significantly lower in patients who died (25 +/- 12 ms) or suffered an AE (26 +/- 13 ms) compared to survivors (40 +/- 19 ms resp. 39 +/- 19 ms; P < 0.001). When limited to patients with depressed 5-minute SDNN, assessment of the HRV index performed better than 5-minute SDNN alone in positive prediction of cardiac events. Preselected assessment of the lowest HRV index in 50% to 20% of the total population yielded a 2-year cardiac event prediction rate as high as analysis of the HRV index in all patients. Long-term HRV assessment for risk stratification after MI in patients preselected by depressed short-term SDNN is safe and efficient, and allows a practical identification of patients with the highest likelihood of cardiac events during long-term follow-up.

Aged↗

PubMed2006

Risk stratification in the asymptomatic child with Wolff-Parkinson-White syndrome.

PURPOSE OF REVIEW: As the safety and efficacy of invasive electrophysiologic studies and ablation therapy in pediatrics improves, there has been a greater interest in developing adequate risk stratification criteria for the asymptomatic pediatric patient with Wolff-Parkinson-White syndrome. This review will discuss the recent literature regarding this debate. RECENT FINDINGS: Recent retrospective and prospective studies of Wolff-Parkinson-White syndrome in asymptomatic pediatric patients have shown that the well established adult criteria for risk stratification may not be applicable in children. Both symptomatic and asymptomatic children had similar accessory pathway effective refractory periods and supraventricular tachycardia inducibility in recent invasive electrophysiologic studies. The first attempt at prospective evaluation of the use of ablation therapy in asymptomatic adult and pediatric patients with the condition has sparked a debate as to the definition of a high-risk patient and the utility of ablation in the asymptomatic patient. SUMMARY: It is still controversial whether the established criteria for risk stratification in adults can be confidently applied to the pediatric patient. The majority of pediatric electrophysiologists use invasive electrophysiologic studies for risk stratification and selection of appropriate therapy. This clinical practice reflects the increasing prevalence and safety of electrophysiologic study and ablation. Further studies to better define indications for study and ablation are still necessary, however, to define accurate criteria for risk stratification in this difficult pediatric problem.

Age Factors↗

PubMed2003

Practical applications in stress echocardiography: risk stratification and prognosis in patients with known or suspected ischemic heart disease.

OBJECTIVES: The purpose of this study was to define appropriate parameters for risk stratification and prognosis in patients undergoing stress echocardiography. BACKGROUND: Stress echocardiography is an established technique for the diagnosis of coronary artery disease. However, current data on risk stratification of patients undergoing stress echocardiography are limited. METHODS: We evaluated 1,500 patients (59 +/- 13 years old; 51% male) undergoing stress echocardiography (34% with treadmill exercise and 66% with dobutamine). Resting left ventricular ejection fraction (EF) and regional wall motion were assessed by the consensus of two echocardiographers. Follow-up (mean 2.7 +/- 1.0 years) for confirmed non-fatal myocardial infarction (n = 31) and cardiac death (n = 44) were performed. RESULTS: By univariate analysis, both the peak wall motion score index (WMSI) (p < 0.0001) and EF (p < 0.0001) were significant predictors of cardiac events. Peak WMSI effectively risk stratified patients into low (0.9%/year), intermediate (3.1%/year), and high (5.2%/year) risk groups (p < 0.0001). A threshold of 45% EF provided further risk stratification of all WMSI groups. By multivariate logistic regression analysis, peak WMSI (relative risk [RR] 2.1, 95% confidence interval [CI] 1.0 to 4.4; p = 0.04) and EF (RR 1.0, 95% CI 0.9 to 1.0; p = 0.01) were both predictors of cardiac events. CONCLUSIONS: Stress echocardiography yields prognostic information for risk stratification of patients with known or suspected ischemic heart disease. A normal stress echocardiographic study (peak WMSI = 1.0) confers a benign prognosis (0.9%/year cardiac event rate). Peak WMSI >1.7 and EF < or =45% are independent markers of patients at high risk of an adverse clinical outcome.

Echocardiography, Stress↗

PubMed2007

Delay in invasive risk stratification of women with acute coronary syndrome is associated with worse outcomes.

BACKGROUND: Invasive risk stratification in patients with acute coronary syndromes (ACS) has been shown to improve outcomes. There is paucity of data on women undergoing invasive risk stratification. We investigated whether the time to coronary angiography affects survival of female patients admitted with ACS. METHOD: Female patients admitted to the coronary intensive care unit with ACS between 1/1/97 and 12/31/00 and undergoing coronary angiography during same hospitalization were divided into three groups based on the time to angiography: same day, 1-2 days and >2 days. The baseline clinical features, angiography results and outcomes were compared between the angiography groups. RESULTS: Of the total 350 female patients who fulfilled the inclusion criteria, 63% underwent angiography within two days of presentation. Three year mortality rates in women undergoing angiography on the same day, 1-2 days and >2-days were 7%, 7% and 22% respectively (p = 0.001). Using multivariate analysis, angiography beyond 2 days was a significant predictor of mortality among women (OR 2.6, 95% CI 1.3-5.0, p = 0.006) after adjusting for confounding variables. CONCLUSION: Later invasive risk stratification after 2 days of presentation in women with ACS is associated with worse survivial. Gender should not be a reason to defer early coronary angiography in these patients.

Aged↗

PubMed1990

Assessment of post-infarction jeopardized myocardium by vasodilation--thallium-201 tomography: impact on risk stratification.

For the purpose of risk stratification 80 consecutive patients (mean age 58 +/- 7 years) with a chest pain syndrome after documented myocardial infarction underwent tomographic vasodilation-redistribution thallium-201 perfusion imaging, using 0.56 mg kg-1 intravenous dipyridamole. Tomograms were analysed for size and location of reversible and fixed perfusion defects and correlated to angiographic characteristics, left ventricular ejection fraction and wall motion, collateral status and 1-year prognosis, as measured by cardiac events within 12 months. No serious side-effects were noted with the diagnostic use of intravenous dipyridamole. According to the perfusion pattern three subgroups of post-infarction patients were identified: (1) by ischaemia at a distance with redistribution in non-infarct related territories (n = 48); (2) by peri-infarctional ischaemia with redistribution in the territory of the 'infarct artery' (n = 9); and (3) by exclusively fixed defects without redistribution (n = 23). Ischaemia at a distance was associated with a larger reversible defect than peri-infarctional ischaemia (P less than 0.05) and the pattern without redistribution (P less than 0.005); the fixed defect size, however, was similar in all three subgroups. In addition, the severity of coronary artery disease (Gensini score and number of diseased vessels) and the degree of collateralization was higher in the presence of a redistribution pattern (P less than 0.05), although no significant differences in global and regional function were noted as a function of thallium-201 redistribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

A new model for risk stratification and delivery of cardiovascular rehabilitation services in the long-term clinical management of patients with coronary artery disease.

This model for risk stratification includes variables that classify patients for Risk of Event similar to current models of risk stratification, as well as variables that stratify patients for Risk of Progression of Atherosclerosis by established risk factors. Categories of risk are established using accepted data from the literature for each risk factor that targets regression or plaque stabilization as the goal for Low Risk. A case-rate charging system and the proposed removal of time restrictions for length of cardiovascular rehabilitation fit neatly into the present climate for health care. Health maintenance organizations will be seeking programs that use similar models to address cost issues inherent in cardiovascular rehabilitation programs under current fee-for-service models. Improved outcomes will also be targets for these programs and case-management lends itself to disease management, thus, improved outcomes. Tracking outcomes becomes even more important to both the provider and the insurer because results drive referrals. Likewise, removal of the time restriction for cardiovascular rehabilitation allows programs to individualize care and to target risk factors that are not only most deleterious, but also where patients show readiness for change. The changing environment of health care virtually mandates change in cardiovascular rehabilitation. It is imperative that programs manage the disease process, are effective in achieving outcomes that affect both patient function and the disease process, and are cost effective. This model for risk stratification and delivery of services addresses these requirements and provides a beginning for implementing these changes in cardiovascular rehabilitation.

Coronary Artery Disease↗

PubMed2005

Acute coronary syndromes: risk stratification and initial management.

For patients who have acute coronary syndromes (ACS), risk stratification is key to initiating appropriate treatment. For ST-segment elevation MI, immediate reperfusion therapy is needed, and thus rapid identification of ST elevation on the ECG is critical. Then, having a standardized protocol for rapid treatment- with either primary percutaneous coronary intervention or thrombolysis - is critical. For unstable angina/non-ST elevation ACS, after first identifying the patients who have a higher likelihood of actually having an ACS (as opposed to noncardiac chest pain) stratification to high versus lower risk is needed to choose appropriate therapies. Thus, it is important for risk stratification to be a central part of all management of patients who have ACS.

Acute Disease↗

PubMed2001

Post-myocardial infarction risk stratification in elderly patients.

BACKGROUND: The purpose of this study was to examine the use of post-myocardial infarction (MI) risk stratification in the elderly. Although expert panels have recommended risk stratification after MI, limited data are available on whether patients actually undergo suggested testing. In particular, concern has been raised that the elderly, who are at high risk for recurrent ischemia and short-term death, are not referred as often as younger patients for post-MI testing. METHODS: We studied the records of 192,311 Medicare patients (age > or = 65 years) admitted with MI between January 1992 and November 1992. By combining Medicare part A and part B data, we created a longitudinal record of patient care within 60 days of an MI admission. We describe the pattern of post-MI testing for ischemia and left ventricular function and outcomes as a function of patient age. RESULTS: Patients > or = 75 years of age were significantly less likely than patients 65 to 74 years of age to have either cardiac catheterization (17% vs 43%) or any test for coronary artery disease severity (24% vs 53%). They were also less likely to have a test of left ventricular function (61% vs 76%). Even after adjustment for baseline characteristics, older patients remained less likely than younger patients to have an assessment of coronary artery disease severity (odds ratio, 0.44) or left ventricular function (odds ratio, 0.65). CONCLUSIONS: Post-MI risk stratification declines with age and falls short of recommendations in our nation's elderly. This lack of testing may result in lost opportunities for therapeutic interventions in this high-risk group.

Aged↗

PubMed2006

[Risk stratification of patients with diabetes mellitus undergoing coronary artery bypass grafting--a comparison of statistical methods].

Among the coronary bypass patients from our Datamart database, we found a prevalence of 29.6% of diagnosed diabetics. 5.2% of the patients without a diagnosis of diabetes mellitus and a fasting plasma glucose level > 125 mg/dl were defined as undiagnosed diabetics. The objective of this paper was to compare univariate methods and techniques for risk stratification to determine, whether undiagnosed diabetes is per se a risk factor for increased ventilation time and length of ICU stay, and for increased prevalence of resuscitation, reintubation and 30-d mortality for diabetics in heart surgery. Univariate comparisons reveals that undiagnosed diabetics needed resuscitation significantly more often and had an increased ventilation time, while the length of ICU stay was significantly reduced. The significantly different distribution between the diabetics groups of 11 from 32 attributes examined, demands the use of methods for risk stratification. Both risk adjusted methods regression and matching confirm that undiagnosed diabetics had an increased ventilation time and an increased prevalence of resuscitation, while the length of ICU stay was not significantly reduced. A homogeneous distribution of the patient characteristics in the two diabetics groups could be achieved through a statistical matching method using the propensity score. In contrast to the regression analysis, a significantly increased prevalence of reintubation in undiagnosed diabetics was found. Based on an example of undiagnosed diabetics in heart surgery, the presented study reveals the necessity and the possibilities of techniques for risk stratification in retrospective analysis and shows how the potential of data collection from daily clinical practice can be used in an effective way.

Coronary Artery Bypass↗

PubMed2000

Prospective evaluation of 3 risk stratification scores in cardiac surgery.

BACKGROUND: The aim of the study was to evaluate 3 different risk stratification scores in cardiac surgery, based on the hospital results of 1,299 patients. METHODS: From June 1995 to December 1997, all patients (n = 1,299) undergoing coronary artery bypass grafting (CABG) and/or heart valve surgery were prospectively enrolled. The postoperative in-hospital outcome (mortality, morbidity and length of hospital stay) was analysed in relation to three different risk stratification scores (Parsonnet, Higgins and French score). RESULTS: The results of 1,299 patients (mean age 62.8 +/- 10.2 years) were analysed. 10 patients died, accounting for a total mortality of 0.8%. 13 patients (1%) underwent cardiopulmonary resuscitation. In 25 patients (1.9%), perioperative myocardial infarction occurred. Performance of the 3 systems was assessed by evaluating discrimination with receiver operating characteristic (ROC) curves. The area under the ROC curve was 0.761 for Parsonnet, 0.786 for Higgins and 0.798 for French score. The French and the Higgins score showed an increase of in-hospital mortality, morbidity and length of stay in relation to increasing risk classes. CONCLUSION: For objective evaluation of the outcome in cardiac surgery, case-mix severity needs to be considered, which is reflected by preoperative risk stratification scores. In our study, all the 3 scores showed a high discrimination and are appropriate tools to assess mortality in cardiac surgery. Especially the French and the Higgins score (restricted to 5 groups), due to their simplicity, were useful to predict postoperative outcome in clinical routine.

Adolescent↗

PubMed2003

QRS duration and prediction of mortality in patients undergoing risk stratification for ventricular arrhythmias.

This study tested the hypothesis that prolonged QRS duration independently predicts long-term mortality in patients who underwent risk stratification and treatment for ventricular arrhythmias. Patients who underwent risk stratification by electrophysiologic study were identified. Electrophysiologic study results were defined as positive if sustained monomorphic ventricular tachycardia was induced. Mortality was the primary end point. Of 915 patients studied, mean left ventricular (LV) ejection fraction (EF) was 35.3 +/- 15.7%, 608 (66.4%) had coronary artery disease, 233 (25.5%) had positive electrophysiologic study findings, 298 (32.6%) received implantable cardioverter-defibrillators, and 174 (19%) died (mean follow-up 35.0 +/- 15.0 months). Cox regression analysis identified older age, coronary artery disease, digoxin use, absence of beta blockers, lower LVEF, and prolonged QRS duration to be independent predictors of mortality. QRS duration > or =130 ms, present in 33.6% of patients, was associated with a twofold increase in mortality (hazard ratio 2.1, 95% confidence interval 1.5 to 2.8; p <0.0001). For every 10 ms increase in QRS duration, mortality rate increased 10%. In a subgroup of patients with coronary artery disease and LVEF < or =30%, prolonged QRS duration remained an independent predictor of mortality (hazard ratio 2.6, 95% confidence interval 1.6 to 4.2; p <0.0001). Thus, prolonged QRS duration is a strong independent marker of long-term mortality in patients who undergo risk stratification for ventricular arrhythmias. Whether QRS duration represents only a marker for mortality or if modification of this factor using resynchronization therapies will impact mortality merits further study.

Aged↗

PubMedDate not supplied

Risk stratification for exercise training in cardiac patients: do the proposed guidelines work?

PURPOSE: Four authoritative organizations (American Association of Cardiovascular and Pulmonary Rehabilitation [AACVPR], the American College of Cardiology [ACC], the American College of Physicians [ACP], and the American Heart Association [AHA]) have risk stratification guidelines for supervised exercise in patients with cardiovascular disease. The ability of the guidelines to predict exercise complications is untested. METHODS: A prospective sample was evaluated that included 239 patients enrolled for a total of 5720 patient exercise hours in a phase II supervised outpatient cardiac rehabilitation exercise program between December 1, 1992, and June 16, 1995, who had had preprogram stress testing and/or left ventricular ejection fraction determination. Complications during supervised exercise were measured. RESULTS: Overall, 12 patients experienced complications during supervised exercise. None of the guidelines was predictive of complications (positive predictive values, 3-7%). Regression analyses demonstrated that current cigarette smoking was the only predictor of complications. There was reasonable correlation of patient risk stratification among the four guidelines (r = 0.19-0.47; P < 0.0001). CONCLUSIONS: Currently proposed exercise risk stratification guidelines are not predictive of complications during supervised exercise. Further work is needed before exercise risk stratification guidelines are used to adjudicate use of supervised services.

Aged↗

PubMed2005

Correlation of plasma von Willebrand factor levels, an index of endothelial damage/dysfunction, with two point-based stroke risk stratification scores in atrial fibrillation.

To test the hypothesis that the new CHADS2 and Framingham point-based risk stratification scores could be related to plasma vWf (a plasma index of endothelial damage/dysfunction) and soluble E-selectin (an index of endothelial activation) levels in a large cohort of AF patients, we studied 200 consecutive patients (101 male; 72+/-9 years) attending our anti-coagulation clinic for the initiation of anticoagulation treatment with acenocoumarol. AF patients had a median CHADS2 score of 2 (1-2) and a median Framingham point-based risk score of 14 (9-21). Results of research indices in our AF patients were as follows: vWf 142.8+/-41.8 IU/dL and sE-sel 44 (31-62) ng/mL. There were significant correlations between plasma vWf levels and both risk CHADS2 and Framingham risk scores (vWf-CHADS2 risk score: Spearman, r=0.249, p<0.001; vWf-Framingham risk score: r=0.294, p<0.001). sE-sel did not show any significant correlation with both risk scores (sE-sel-CHADS2 risk score: r=-0.054, p=0.460; sE-sel-Framingham risk score: r=0.062, p=0.460). There were no statistically significant correlations between vWf and sE-sel (r=-0.127, p=0.081). Both CHADS2 and Framingham risk scores were significantly correlated with each other, r=0.627, p<0.001. In conclusion, in a wide cohort of non-selected and consecutive AF patients, endothelial damage/dysfunction (assessed by plasma vWf levels) but not endothelial activation (sE-sel) correlated with two new risk stratification scores for stroke in AF. Further prospective studies are needed to assess the prognostic role of prothrombotic indices in AF in relation to stroke and thromboembolic events, and their role in complementing clinical risk stratification schemas.

Aged↗

PubMed1992

[Risk stratification in patients recuperating from acute myocardial infarct. How useful is it?].

The author intended to discuss the individual prognostic value of some best known risk stratification variables after Acute Myocardial Infarction (AMI), whose tests have a low diagnostic accuracy due to high risk individual variations, emphasizing the statistic errors of using one single risk variable on post AMI risk stratification schemes. Some epidemiologic data about AMI survivors are reviewed and the author concludes by emphasizing the importance of using more AMI population characteristics on post AMI risk stratification schemes.

Arrhythmias, Cardiac↗

PubMed2025

Breast Cancer Risk Stratification in Black Women: Current Status and Potential Solutions to Improve Accuracy.

Breast cancer risk stratification models identify individuals at increased risk, allowing earlier screening than for those at average risk and potentially improving health outcomes. Due to the increasing rates of breast cancer in individuals aged <40 years, especially among Black females, the American College of Radiology now recommends all females initiate breast cancer risk assessment by age 25 years. Several breast cancer risk prediction models are readily available, including the Gail Model, Breast Cancer Surveillance Consortium Risk Calculator, BOADICEA, and Tyrer-Cuzick Model. However, because these models were primarily developed using data from White women of European ancestry, they may underestimate risk in Black women. Indeed, current evidence suggests that these models underpredict breast cancer risk among Black women, particularly those of African ancestry. Although cancer risk prediction models typically incorporate personal characteristics, family history of cancer, and hormonal and lifestyle factors, inherited breast cancer genes can also increase risk for breast cancer. Beyond monogenic inherited breast cancer genes that increase breast cancer risk, emerging data suggest that single nucleotide polymorphisms identified through genome-wide association studies (GWAS) may be used to generate polygenic risk scores, which may further refine breast cancer risk. However, GWAS data are also primarily gathered from European ancestry females, further reducing the ability to accurately stratify breast cancer risk in non-European ancestry populations. Current data highlight the importance of ensuring representation from all populations in developing cancer risk prediction models, conducting genomics research, and designing effective implementation strategies to enhance the use of these models in routine clinical care. Although new analytic methods and models are being developed to improve breast cancer risk stratification across populations, it remains critical to assess the utility and calibration of existing and new models to ensure applicability across non-European ancestry populations.

Humans↗

PubMed2006

Risk stratification with electrocardiographic-gated dobutamine stress technetium-99m sestamibi single-photon emission tomographic imaging: value of heart rate response and assessment of left ventricular function.

OBJECTIVES: The purpose of this research was to evaluate the significance of heart rate response to dobutamine and the assessment of left ventricular (LV) function during risk stratification of patients undergoing dobutamine stress myocardial perfusion imaging (DSMPI). BACKGROUND: Dobutamine stress myocardial perfusion imaging has been shown to effectively risk stratify highly selected patients. However, based on perfusion alone, patients with normal and abnormal tests have twice the risk as comparable patients with exercise testing. The added value of assessment of LV function and the heart rate response to dobutamine in risk stratification of these patients is unknown. METHODS: Follow-up information (cardiac death or non-fatal myocardial infarction) was obtained on 1,367 consecutive patients who underwent DSMPI due to inability to perform adequate exercise and contraindications to vasodilators. Perfusion images were interpreted using a 17-segment model. Abnormal perfusion and function were defined as: summed stress score > or =4 and ejection fraction <50%, respectively. RESULTS: Annualized event rates (AERs) were related to the extent/severity of perfusion defects and worsening LV function. A three-risk category model was constructed from combined assessment of perfusion and function, with AERs of 2.4% (both normal), 5.8% (discordant), and 11.3% (both abnormal); p < 0.001. Stress electrocardiogram (ECG) data added incremental value to myocardial perfusion alone but not to combined assessment of perfusion and function. Importantly, inability to achieve 85% of mean predicted heart rate was associated with worse outcomes and was an independent predictor of cardiac events. For patients in whom perfusion, function, and stress ECG response were normal, inability to achieve target heart rate was associated with significantly higher AER (1.5% vs. 3.4%, respectively, p = 0.021). CONCLUSIONS: In highly selected patients undergoing DSMPI, assessment of perfusion and function is effective in risk stratification. The stress ECG and heart rate response to dobutamine have prognostic value and should be incorporated into image interpretation so as to maximize risk stratification.

Aged↗

PubMed2005

Value of pharmacologic stress myocardial perfusion imaging for preoperative risk stratification for aortic surgery.

BACKGROUND: Aortic surgery is an invasive, high-risk noncardiac procedure and the patients who require it have a high prevalence of coronary artery disease. Therefore, preoperative risk stratification for this subset is essential. METHODS AND RESULTS: To assess the perioperative risk for aortic surgery, pharmacologic stress single-photon emission computed tomography (SPECT) was performed in 302 patients: aortic dissection in 56, thoracic aortic aneurysm in 124, and abdominal aortic aneurysm in 122. Not only was the presence or absence of perfusion defects analyzed, but also the 20-segment model. Pharmacologic thallium SPECT revealed negative findings in 210 patients and positives in 92. Perioperative cardiac events occurred in 9 patients: 7 occurred in patients with positive SPECT, and in only 2 of those with negative SPECT (2/210 vs 7/92; p<0.05). Multivariate analysis using logistic regression model revealed that a summed stress score>or=14 was the most important factor to identify patients who subsequently had perioperative cardiac events. CONCLUSIONS: Pharmacologic stress SPECT has significant value in the risk stratification of patients before aortic surgery. In patients with positive SPECT, an aggressive approach to reduce the preoperative risk is necessary, whereas aortic surgery can be performed safely in patients with negative SPECT.

Aged↗

PubMed2001

[Arrhythmia risk stratification in patients with heart failure: prognostic evaluation of arrhythmia risk].

Sudden cardiac death is one of the more frequent causes of death in patients with heart failure. Thus, identification of patients at risk is a major clinical problem not only for the unpredictability of the event but also for the continuous growth of patients' number. The most widely used parameter for risk stratification is ejection fraction. Unfortunately, its predictive accuracy is limited and often it is impossible to distinguish patients with an increased arrhythmic mortality from those with an increased mortality due to pump failure. Heart rate variability and baroreflex sensitivity analysis has been largely utilized to obtain information on autonomic modulation of sinus node as well as to identify patients at risk. However, at variance with results observed in post-myocardial infarction patients, lower values of both parameters have been reported in patients with either an increased total or arrhythmic mortality. More recently, T wave alternans analysis has been found effective in identifying patients with an increased arrhythmic risk. Ongoing studies will provide evidence to support the use of this non-invasive technique in patients with cardiac insufficiency. Finally, the role of programmed electrical stimulation in heart failure patients appears limited. Inducibility of monomorphic sustained ventricular tachycardia seems to correlate better with the presenting clinical arrhythmia than with patient outcome. In conclusion, our capability of identifying heart failure patients at risk for arrhythmic death is far from being satisfactory. It is possible that the combination of results of multiple non-invasive tests such as reduction in ejection fraction and positivity for T wave alternans may not only provide general prognostic information but also facilitate the appropriate identification of patients at risk who may benefit from antiarrhythmic therapy.

Arrhythmias, Cardiac↗