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PubMed1992

Frequency versus time domain analysis of signal-averaged electrocardiograms. III. Stratification of postinfarction patients for arrhythmic events.

The predictive characteristics of spectral temporal analysis and time domain analysis of the signal-averaged electrocardiogram (ECG) for postinfarction arrhythmic events were compared in 257 patients. During a 6-month follow-up period, 7 patients (2.7%) died suddenly and 9 (3.5%) developed spontaneous sustained ventricular tachycardia. The mean numeric values of the standard time domain signal-averaged ECG variables in patients without arrhythmic events differed significantly from those in patients with arrhythmic events. The mean values of the spectral temporal signal-averaged ECG variables did not differ between the two patient groups. A strategy requiring positivity in any two time domain signal-averaged ECG variables provided the optimal receiver operating characteristic curves for predicting arrhythmic events. With spectral temporal analysis, a strategy using the Hanning window and diagnosing a positive signal-averaged ECG when two variables were abnormal provided the optimal curve for predicting arrhythmic events. Receiver operating characteristic curves showed that over a wide range of sensitivity, time domain variables had higher specificity for predicting arrhythmic events than did spectral temporal variables. Time domain analysis also provided significantly fewer false positive results than did spectral temporal analysis up to sensitivity values of 70%. It is concluded that time domain analysis of the signal-averaged ECG is superior to spectral temporal analysis for predicting arrhythmic events after myocardial infarction.

Adult↗
PubMed1993

Use of a regional wall motion score to enhance risk stratification of patients receiving an implantable cardioverter-defibrillator.

OBJECTIVES: We postulated that preoperative assessment of both regional wall motion and left ventricular ejection fraction would serve as an accurate prognostic indicator of long-term cardiac mortality and functional outcome in patients treated with an implantable cardioverter-defibrillator. BACKGROUND: Long-term cardiac mortality has remained high in patients receiving an implantable cardioverter-defibrillator. The ability to risk stratify patients before defibrillator implantation is becoming increasingly important from a medical and economic standpoint. METHODS: The hypothesis was retrospectively tested in 74 patients who had received an implantable cardioverter-defibrillator. Left ventricular ejection fraction and regional wall motion score, derived from centerline chord motion analysis, were calculated for each patient from the preoperative right anterior oblique contrast ventriculogram. Wall motion score was the only significant independent predictor of long-term cardiac mortality and functional status by multivariate analysis because of its enhanced prognostic capability in patients with an ejection fraction in the critical range of 30% to 40%. RESULTS: Patients with an ejection fraction > 40% had a 3-year cardiac mortality rate of 0% compared with 25% for those with an ejection fraction of 30% to 40% and 48% for those with an ejection fraction < 30% (p < 0.05). Similarly, 75% of patients with an ejection fraction > 40% were in New York Heart Association functional class I or II during long-term follow-up compared with 59% of those with an ejection fraction 30% to 40% and 29% of those with an ejection fraction < 30%. Among patients with an ejection fraction of 30% to 40%, those with a wall motion score > 16% had a 3-year cardiac mortality rate of 0% compared with 71% of those with a wall motion score < or = 16% (p = 0.002). In addition, 86% of patients with a wall motion score > 16% were in functional class I or II during long-term follow-up compared with 13% of those with a wall motion score < or = 16% (p = 0.001). CONCLUSIONS: Long-term cardiac mortality and functional outcome in patients receiving an implantable cardioverter-defibrillator can be predicted if the left ventricular ejection fraction and regional wall motion score are measured preoperatively.

Activities of Daily Living↗
PubMed2004

Autonomic profile and arrhythmic risk stratification after surgical repair of tetralogy of Fallot.

BACKGROUND: Severe ventricular arrhythmias represent one of the main causes of mortality after repair of tetralogy of Fallot. Their appearance is primarily caused by the large ventricular scar created by surgical intervention. However, the role of autonomic activity as a modulating factor should be considered. The aim of our study was to evaluate this activity in a low-risk group of patients operated on for TOF and its correlation with the occurrence of sustained ventricular tachycardia. METHODS AND RESULTS: The study group included 38 patients with a mean age of 31 +/- 10 years, selected out of 76 subjects operated on for total correction of tetralogy of Fallot. After a mean interval of 21.9 +/- 6 years from surgical procedure, they underwent electrocardiography, echocardiography, and time domain heart rate variability (HRV) analysis obtained by 24-hour Holter monitoring. Thirty-five healthy subjects comprised the control group for HRV analysis. During a mean follow-up of 6.2 +/- 3 years, 8 patients experienced episodes of sustained ventricular tachycardia. Among different HRV parameters, the standard deviation of all normal beat intervals showed a significant reduction in this group of patients (91.7 +/- 19 versus 133.4 +/- 46, P < .02). Echocardiographic examination demonstrated an increased left ventricular end diastolic volume (85.6 +/- 55 versus 61.3 +/- 13 mL/m(2), P < .05) and a reduced left ventricle ejection fraction (53.9 +/- 9 versus 61.0 +/- 6 %, P < .01) in arrhythmic patients. QRS duration was similar in patients with or without sustained ventricular tachycardia. CONCLUSIONS: Patients after surgical correction of tetralogy of Fallot, considered to be at low risk, showed a significant incidence of severe ventricular arrhythmias. HRV analysis seems to be a useful method for identifying arrhythmic patients, and the standard deviation of all normal beat intervals appears to be the more helpful index.

Adult↗
PubMed2006

Wall motion score index and ejection fraction for risk stratification after acute myocardial infarction.

BACKGROUND: The prognostic importance of regional systolic function, as assessed by wall motion score index (WMSI), compared with global function, as assessed by left ventricular ejection fraction (LVEF), has not been assessed in large populations after acute myocardial infarction. METHODS: Echocardiograms, including the assessment of WMSI and LVEF, were performed in 767 patients with acute myocardial infarction at a median of 1 day (25th and 75th percentiles 0-2 days) after admission. Patients were followed for a median of 19 months (range 12-28 months). Cox proportional hazards models were constructed for the primary study end point (all-cause mortality) and for a secondary end point (hospitalization for congestive heart failure). RESULTS: During follow-up (median 40 months; range 32-50 months), 216 patients died and 54 patients were hospitalized for congestive heart failure. By univariate analysis, both LVEF (P < .0001) and WMSI (P < .0001) were powerful predictors of all-cause mortality. By a forward conditional Cox model, WMSI proved to be an independent predictor of death (hazard ratio 1.15 per 0.2-unit increase, 95% CI 1.10-1.21, P < .0001). When WMSI was included in the model, LVEF did not provide additional prognostic information (P = .77). Wall motion score index also proved to be an independent predictor of hospitalization for congestive heart failure (hazard ratio 1.21 per 0.2-unit increase, 95% CI 1.07-1.37, P = .002), whereas LVEF did not (P = .56). CONCLUSION: Both LVEF and WMSI provide powerful prognostic information after acute myocardial infarction; however, the predictive power of WMSI is greater.

Aged↗
PubMed2006

Clinical characteristics, process of care, and outcomes of Hispanic patients presenting with non-ST-segment elevation acute coronary syndromes: results from Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines (CRUSADE).

BACKGROUND: Data regarding the management of non-ST-segment elevation acute coronary syndromes (NSTE ACS) in Hispanic patients, the largest and fastest-growing minority in the United States, are scarce. METHODS: We sought to describe the clinical characteristics, process of care, and outcomes of Hispanics presenting with NSTE ACS at US hospitals. We compared baseline characteristics, resource use, and inhospital mortality among 3936 Hispanics and 90280 non-Hispanic whites with NSTE ACS from the CRUSADE Quality Improvement Initiative. RESULTS: The regional distribution of Hispanics in CRUSADE paralleled that in the US Census. Hispanics were younger (65 vs 70 years, P < .0001) and had less hyperlipidemia (45.4% vs 49.0%, P < .0001) but were more likely to be hypertensive (72.2% vs 67.9%, P < .0001) and diabetic (46.5% vs 30.9%, P < .0001). Hispanics were also more likely to be uninsured (12.5% vs 5.1%, P < .001). During hospitalization, Hispanics were more often managed conservatively, undergoing stress tests more frequently (13.0% vs 10.1%, P < .0001), with less use of cardiac catheterization within 48 hours (48.7% vs 55.5%, P < .0001) or percutaneous coronary intervention (39.6% vs 46.4%, P < .0001) at any time. Hispanics received similar discharge treatments but were less frequently referred for cardiac rehabilitation (38.5% vs 49.2%, P < .0001). Adjusted inhospital mortality was similar in both groups (odds ratio 0.87, 95% CI 0.72-1.05). CONCLUSIONS: Although hispanics have a different risk factor profile and are treated less aggressively during hospitalization when they present with NSTE ACS, these treatment differences do not appear to affect inhospital outcomes. Further research is warranted to explore the long-term consequences of these findings.

Aged↗
PubMed2006

The obesity paradox in non-ST-segment elevation acute coronary syndromes: results from the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the American College of Cardiology/American Heart Association Guidelines Quality Improvement Initiative.

BACKGROUND: Although obesity is a known risk factor for coronary artery disease, its impact on the presentation, treatment, and outcome of patients with acute coronary syndromes (ACS) has not been well studied. METHODS: Using data from the CRUSADE Initiative, we compared inhospital treatments and clinical outcomes of 80845 patients with high-risk non-ST-segment elevation (NSTE) ACS (positive cardiac markers and/or ischemic ST-segment changes) to determine whether there was an association with body mass index (BMI [kg/m2]). Patient weights were categorized according to World Health Organization classifications: Underweight (BMI <18.5), Normal range (BMI 18.5-24.9), Overweight (BMI 25-29.9), Obese Class I (BMI 30-34.9), Obese Class II (BMI 35-39.9), and Extremely Obese (BMI =40). RESULTS: Most (70.5%) of the CRUSADE patients were classified as overweight or obese; these patients were younger and more likely to present with comorbid conditions, including diabetes mellitus, hypertension, and hyperlipidemia. Medications given during the first 24 hours and invasive cardiac procedures recommended by the American College of Cardiology/American Heart Association guidelines for NSTE ACS were more commonly used in these patients. The incidence of death and death and reinfarction, adjusted for covariates, were generally lower in overweight and obese patients, compared with normal-weight patients, but higher in underweight and extremely obese patients. CONCLUSIONS: Most patients with NSTE ACS are overweight or obese. These patients receive more aggressive treatment, and, except for the extremely obese, have less adverse outcomes compared with underweight and normal-weight patients. Although obesity appears to be a risk factor for developing ACS at a younger age, it also appears to be associated with more aggressive ACS management and, ultimately, improved outcomes.

Aged↗
PubMed2006

Risk stratification of patients with chronic kidney disease: results of screening strategies incorporating clinical risk scoring and dobutamine stress echocardiography.

BACKGROUND: Cardiac disease is the principal cause of death in patients with chronic kidney disease (CKD). Ischemia at dobutamine stress echocardiography (DSE) is associated with adverse events in these patients. We sought the efficacy of combining clinical risk evaluation with DSE. METHODS: We allocated 244 patients with CKD (mean age 54 years, 140 men, 169 dialysis-dependent at baseline) into low- and high-risk groups based on two disease-specific scores and the Framingham risk model. All underwent DSE and were further stratified according to DSE results. Patients were followed over 20 +/- 14 months for events (death, myocardial infarction, acute coronary syndrome). RESULTS: There were 49 deaths and 32 cardiac events. Using the different clinical scores, allocation of high risk varied from 34% to 79% of patients, and 39% to 50% of high-risk patients had an abnormal DSE. In the high-risk groups, depending on the clinical score chosen, 25% to 44% with an abnormal DSE had a cardiac event, compared with 8% to 22% with a normal DSE. Cardiac events occurred in 2.0%, 3.1%, and 9.7% of the low-risk patients, using the two disease-specific and Framingham scores, respectively, and DSE results did not add to risk evaluation in this subgroup. Independent DSE predictors of cardiac events were a lower resting diastolic blood pressure, angina during the test, and the combination of ischemia with resting left ventricular dysfunction. CONCLUSION: In CKD patients, high-risk findings by DSE can predict outcome. A stepwise strategy of combining clinical risk scores with DSE for CAD screening in CKD reduces the number of tests required and identifies a high-risk subgroup among whom DSE results more effectively stratify high and low risk.

Adult↗
PubMed2006

Prevalence, predictors, and outcomes of patients with non-ST-segment elevation myocardial infarction and insignificant coronary artery disease: results from the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines (CRUSADE) initiative.

BACKGROUND: Unlike ST-segment elevation myocardial infarction, the degree of stenosis and physiology of ischemia varies in patients with non-ST-segment elevation myocardial infarction (NSTEMI). The prevalence, predictors, and outcomes of patients with NSTEMI who lack significant epicardial coronary artery disease (CAD) in routine clinical practice remain poorly characterized. We sought to determine the prevalence, predictors, and outcomes of patients with NSTEMI and insignificant CAD. METHODS: We analyzed 38301 patients with NSTEMI in the CRUSADE quality improvement initiative who underwent cardiac catheterization to determine the prevalence and factors associated with insignificant CAD (all coronary stenoses <50%) and inhospital outcomes for patients with and without CAD. A multivariable model was used to determine the factors associated with insignificant CAD. RESULTS: A total of 3306 (8.6%) of 38301 patients had insignificant CAD. The strongest multivariable predictors of insignificant CAD were female sex (odds ratio 2.8, 95% CI 2.6-3.1), younger age (odds ratio per 10-year decrease 1.5, 95% CI 1.5-1.6), and lack of current/recent smoking (odds ratio 1.9, 95% CI 1.7-2.0). Inhospital rates of death were 0.65% for patients with insignificant CAD compared with 2.36% for patients with CAD (P < .0001). CONCLUSION: Insignificant CAD is present in 9% of patients with NSTEMI and is associated with a low incidence of adverse outcomes. The strongest predictors of insignificant CAD are female sex and younger age. These findings underscore the need for research to understand the pathophysiology of myocardial infarction in this population.

Acute Disease↗
PubMed2007

Risk stratification for patients undergoing nonurgent percutaneous coronary intervention using N-terminal pro-B-type natriuretic peptide: a Clopidogrel for the Reduction of Events During Observation (CREDO) substudy.

BACKGROUND: The utility of N-terminal pro-BNP (NT-proBNP) measurement as a prognostic marker during nonurgent percutaneous coronary intervention (PCI) has been suggested in several studies. The comparative prognostic values between NT-proBNP levels and left ventricular ejection fraction (LVEF) in the nonurgent PCI setting are unclear. METHODS: CREDO was a double blind, placebo-controlled, randomized trial comparing 2 clopidogrel regimens before and after nonurgent PCI. Baseline NT-proBNP levels and LVEF were measured in 1468 subjects using the Roche Elecsys proBNP assay (Roche Diagnostics, Indianapolis, IN), and the 1-year combined end point of death/myocardial infarction (MI)/stroke was analyzed according to NT-proBNP quartiles in impaired and preserved LVEF. RESULTS: In this patient cohort (mean age 61.6 +/- 10 years, 22% with LVEF < 50%), the median NT-proBNP level was 131 pg/mL. Increasing quartiles of NT-proBNP were associated with a higher rate of death, MI, and the combined end point (but not stroke) at 1 year, including those with LVEF > or = 50% (P < .001 for trend). This prognostic power for death and MI remained robust even when adjusted for other clinical or biochemical markers including cardiac troponin, creatinine clearance, and high-sensitive C-reactive protein (hazard ratio 1.249, P = .006). Despite its robust prognostic value, baseline NT-proBNP levels did not identify patients with enhanced benefit from pre-procedural and prolonged clopidogrel therapy. CONCLUSIONS: In patients undergoing a nonurgent PCI, NT-proBNP levels may provide important prognostic value for death and MI, even in patients with preserved cardiac function, However, NT-proBNP levels were unable to identify patients with enhanced benefit from pre-procedural and prolonged clopidogrel therapy.

Aged↗
PubMed2004

The effect of limited English proficiency on admission rates from a pediatric ED: stratification by triage acuity.

The objectives of this study were to determine the effect of Limited English Proficiency (LEP) visits and acuity status on admission rates from a pediatric ED. A retrospective cohort study was performed using a fully computerized medical record, which includes information on language spoken, triage acuity, and disposition. Data was collected on all patient visits from July 2002 to November 2002 from a tertiary-care pediatric ED. Admission rates and acuity status for LEP and non-LEP patients were compared. A total of 13,585 patient visits were identified, of which 12,416 fit the study criteria. There were 244 LEP patient visits, of which 206 were Spanish-speaking. There were 12,172 English-speaking patient visits. Compared with English-speaking visits, LEP visits were more likely to be triaged as high acuity (25.8% vs. 16.1%, P < .001). LEP patients were more likely to be admitted to the hospital (22.1% vs. 13%, P < .001). For high- and low-acuity patients, no significant differences in admission rates were seen between LEP and English-speaking patients. In contrast, moderate-acuity LEP visits showed a significantly increased admission rate compared to moderate acuity English visits (22.5% vs. 12.4%, P = .005). Similar trends were seen among Spanish-speaking LEP patients. Differences in medical disposition from the ED were found between English-speaking and LEP patient visits. There were higher rates of admission for LEP patients, particularly among moderate-acuity visits. This highlights disparities of care for this vulnerable population.

Child↗
PubMed2026

Additive value of polygenic risk and family history for coronary heart disease risk stratification in two diverse US cohorts.

Whether polygenic risk, monogenic familial hypercholesterolemia (FH), and family history (FamHx) are additively informative for coronary heart disease (CHD) risk prediction across self-identified race/ethnicity (SIRE) groups has not been established. In two diverse cohorts-Electronic Medical Records and Genomics (eMERGE) phase IV (eIV; n = 19,348) and All of Us (AoU; n = 239,645)-we quantified the associations of a polygenic risk score (PRSCHD), pathogenic/likely pathogenic variants in genes associated with FH, and FamHx with CHD and evaluated their incremental value when added to the pooled cohort equations (PCEs). CHD was defined as myocardial infarction, unstable angina, or coronary revascularization. We modeled associations with multivariable logistic regression (prevalent CHD in eIV) and Cox proportional hazards (incident CHD in AoU) and characterized predictive performance with the c-statistic and reclassification and decision-curve net benefits across actionable 10-year risk thresholds. The effects of PRSCHD and FamHx were independent and additive in both cohorts and consistent across White, Black, and Latino SIRE groups. In eIV, adding PRSCHD and FamHx to the PCE increased the c-statistic for prevalent CHD from 0.719 to 0.753 (p-diff = 9.1 &#xd7; 10-3) and reclassified 18.8% of participants at the 7.5% 10-year threshold, yielding approximately 4 additional true-positive CHD identifications per 1,000 screened. Net benefit gains were observed between the 7.5% and 10% thresholds across all three SIRE groups. In conclusion, PRSCHD and FamHx were independently and additively associated with CHD across major SIRE groups in two diverse cohorts in the United States (US), motivating the addition of these factors to clinical risk algorithms.

Humans↗
PubMed2004

Novel stress echocardiographic model incorporating the extent and severity of wall motion abnormality for risk stratification and prognosis.

The prognostic value of stress echocardiography to predict future cardiac events using the extent and severity of wall motion abnormalities is not well defined. The objective of this study was to develop and validate a prognostic model for interpretation of stress echocardiographic studies by using the extent and severity of wall motion abnormalities. We evaluated 1,500 patients (59 +/- 13 years old; 51% men) who underwent stress echocardiography (34% on the treadmill exercise and 66% on dobutamine). Left ventricular regional wall motion was assessed by consensus of 2 experienced echocardiographers. Follow-up periods (mean 2.7 +/- 1.0 years) for confirmed myocardial infarction (n = 31) and cardiac death (n = 44) were identified. Multivariate regression analysis identified 2 independent predictors of cardiac events: the number of left ventricular wall segments with new wall motion abnormalities (an index of the extent of ischemia) and the maximal magnitude of new wall motion abnormalities (an index of the severity of ischemia). The ischemic extent (chi-square 48.7, p <0.0001) and maximal severity (chi-square 52.0, p <0.0001) were exponentially correlated with an increase in event rate. On the basis of these data, a prognostic model was defined that uses ischemic extent and maximal severity as stress-dependent orthogonal variables. With this 3-dimensional model, the predicted event rate ranged over sevenfold, from a low of 0.9%/year in patients without any wall motion abnormalities to a high of 6.7%/year in patients with extensive and severe wall motion abnormalities. The extent and severity of wall motion abnormalities by stress echocardiography are independent and cumulative predictors of prognosis in patients who have suspected or known ischemic heart disease.

Aged↗
PubMed2004

Impact of contemporary guideline compliance on risk stratification models for acute coronary syndromes in The Registry of Acute Coronary Syndromes.

We compared the predictive value of the Rush score with the Thrombolysis In Myocardial Infarction (TIMI) risk score in unselected patients with an acute coronary syndrome and evaluated the effect of compliance with established guidelines on the accuracy of these models. The Registry of Acute Coronary Syndromes is a retrospective registry of 3,754 consecutive patients (38% women; mean age 67 years) who presented with acute coronary syndrome to the emergency department between April 1, 1999, and December 31, 2000, at 9 hospitals. The primary end point was death, myocardial infarction, or urgent revascularization during hospitalization. Rush classification was based on quartiles of predicted risk of cardiac complication (<2% for class I vs >15% for class IV). The TIMI score was implemented as published. Compliance with guidelines for acute coronary syndrome was assessed with a 4-point scale based on the aggregate use of aspirin, beta blockers, heparin, and glycoprotein IIb/IIIa inhibitors. Fifteen percent of patients met the primary end point. The primary end point rates for TIMI scores 0/1, 2, 3, 4, 5, and 6/7 were 11%, 14%, 13%, 11%, 14%, and 12%, respectively (p = NS). The primary end point rates for Rush classes I, II, III, and IV were 6%, 8%, 9%, and 17%, respectively (p <0.001). After controlling for compliance with established guidelines, the odds ratio of an event increased by 46% for each unit increase in Rush score (p <0.001). After adjusting for the Rush score, the odds ratio decreased by 54% for each unit increase in compliance (p <0.001). Thus, compliance with current American College of Cardiology/American Heart Association guidelines significantly improves prognosis, regardless of the risk score. The use of established risk scores may overestimate event rates in unselected populations.

Adrenergic beta-Antagonists↗