Early prediction of mortality in patients with acute myocardial infarction: a prospective study of clinical and radionuclide risk factors

Magnitude and prognosis associated with ventricular arrhythmias in patients hospitalized with acute coronary syndromes (from the GRACE Registry)

The incidence, prognosis, and factors associated with ventricular arrhythmia (VA) in acute coronary syndrome are unknown. We sought to examine the magnitude, predictors, and outcomes of in-hospital VA in patients with acute coronary syndrome. The population comprised 52,380 patients enrolled in the Global Registry of Acute Coronary Events from 1999 to 2005. The proportion who developed VA during hospitalization was 6.9% (1.8% with ventricular tachycardia, 5.1% with ventricular fibrillation or cardiac arrest). The incidence of in-hospital VA decreased over time (8.0% in 1999, 7.0% in 2002, 5.8% in 2005, p <0.001). In-hospital case-fatality rates were higher in patients with versus those without VA (52% vs 1.6%). Several demographic and clinical variables were associated with the occurrence of VA including ST deviation, Killip class, age, initial cardiac markers, serum creatinine and heart rate, and history of selected co-morbidities. Six-month postdischarge mortality was higher in survivors of in-hospital VA versus those who did not develop VA during hospitalization (odds ratio 1.57, 95% confidence interval 1.27 to 1.95). In conclusion, development of VA during hospitalization for acute coronary syndrome was associated with higher in-hospital and 6-month mortalities.

Cardioprotection by intermittent fasting in rats

BACKGROUND

Intermittent fasting (IF), a dietary regimen in which food is available only every other day, increases the life span and reduces the incidence of age-associated diseases in rodents. We have reported neuroprotective effects of IF against ischemic injury of the brain. In this study, we examined the effects of IF on ischemic injury of the heart in rats.

METHODS AND RESULTS

After 3 months of IF or regular every-day feeding (control) diets started in 2-month-old rats, myocardial infarction (MI) was induced by coronary artery ligation. Twenty-four hours after MI, its size in the IF group was 2-fold smaller, the number of apoptotic myocytes in the area at risk was 4-fold less, and the inflammatory response was significantly reduced compared with the control diet group. Serial echocardiography revealed that during 10 weeks after MI (with continuation of the IF regimen), the left ventricular (LV) remodeling and MI expansion that were observed in the control diet group were absent in the IF group. In a subgroup of animals with similar MI size at 1 week after MI, further observation revealed less remodeling, better LV function, and no MI expansion in the IF group compared with the control group.

CONCLUSIONS

IF protects the heart from ischemic injury and attenuates post-MI cardiac remodeling, likely via antiapoptotic and antiinflammatory mechanisms.

Left Ventricular Ejection Fraction Change with Exercise Versus Ejection Fraction at Rest in Coronary Artery Disease: Implications for Using Ejection Fraction Variations in Making Therapeutic Decisions

Previous studies have differed regarding the prognostic importance of the change (Delta) in left ventricular ejection fraction (LVEF) with exercise among patients with known or suspected coronary artery disease (CAD). Data suggest that these discrepancies may be owing to patient selection, including wide interstudy variations in the range of LVEFrest at study entry; however, the impact of LVEFrest on LVEF exercise response has not been adequately addressed. To test the hypothesis that magnitude and variability in DeltaLVEF are systematically related to LVEFrest, we analyzed data from 2655 patients who underwent rest/exercise radionuclide cineangiography for evaluation of clinically evident CAD, stratified into 5 successive LVEFrest subgroups: <30% (n = 205), 30%-44% (n = 563), 45%-59% (n = 1529), 60%-75% (n = 324), and >75% (n = 34). The standard deviation of DeltaLVEF among patients with LVEFrest <30% was found to be half that among patients in the higher LVEFrest subgroups (P < 0.00001, global). The average magnitude of the rise and fall in LVEF with exercise also varied markedly among LVEFrest subgroups (P < 0.0001, global), being smallest among patients with LVEFrest <30%. These findings may explain differences in predictive accuracy of DeltaLVEF noted among various study populations. Further study is needed to determine whether LVEFrest should be used in selecting exercise-based prognostic descriptors in individual patients.

Effect of aging on dynamic cerebral autoregulation during head-up tilt

BACKGROUND AND PURPOSE

Physiological aging is associated with many changes in the cardiovascular and cerebrovascular systems, but dynamic cerebral autoregulation (CA) during supine rest shows no age-related changes. Because syncopal syndromes usually occur during orthostatic stress and their prevalence increases with age, it is important to define the effect of aging on dynamic CA during orthostatic stress.

METHODS

Twenty-five younger subjects (</=40 years) and 25 sex-matched older subjects (>/=60 years) underwent 70 degrees head-up tilt for 30 minutes. Bilateral middle cerebral artery blood flow velocities were measured with transcranial Doppler ultrasound, along with noninvasive continuous measurements of arterial blood pressure, heart rate, and transcutaneous and end-tidal carbon dioxide concentrations. By comparing actual changes in cerebral blood flow velocity to changes predicted by a model based on arterial blood pressure changes, we derived dynamic autoregulatory indexes for each subject for periods before, during, and after tilt.

RESULTS

Younger subjects were a mean of 40 years younger than older subjects (28+/-8 versus 69+/-10 years). Although cerebral blood flow velocity (P<0.001) and baroreceptor sensitivity (P<0.001) were significantly lower at rest in older subjects, autoregulatory indexes were similar in younger and older subjects at all times before, during, and after tilt (P=0.62).

CONCLUSIONS

Although increasing age is associated with lower cardiac baroreceptor sensitivity and cerebral blood flow velocity, dynamic CA during orthostatic stress is unaffected by physiological aging.

[Value of gated-SPECT in defining the post-revascularization prognosis of patients with ischemic cardiomyopathy]

INTRODUCTION AND OBJECTIVES

Gated-SPECT simultaneously evaluates perfusion and ventricular function and could provide important prognostic information in ischemic cardiomyopathy. Our aim was to study the value of gated-SPECT performed before revascularization in a cardioischemic population to predict the outcome of revascularization.

METHODS

One hundred and ten patients who had undergone percutaneous (n = 100) or surgical revascularization were included. Patients underwent sestamibi gated-SPECT before revascularization. After revascularization, they were followed-up for at least 12 months (mean 23.7 months, maximum 44 months). We recorded deaths and a combined clinical event of death, non-fatal infarction, and hospital re-admission for cardiac reasons. We analyzed the prognostic value of clinical, angiographic, and gated-SPECT variables.

RESULTS

During follow-up, there were 14 deaths (6.4%/ year) and 36 cases of combined events (16.5%/year). Multivariate analysis showed that depressed gated-SPECT ejection fraction (threshold 0.30) was the only variable independently related to death (OR = 4.8; 95%CI, 1.6-14.6) and combined event (OR = 2.5; 95%CI, 1.2-4.8). Survival analysis showed that patients with ejection fraction < or = 0.30% had a significantly shorter period of time free of death (33 months [28-38] versus 42 months [40-44]; p = 0.002) and combined events (28 months [23-32] versus 36 months [33-39]; p = 0.007).

CONCLUSIONS

Gated-SPECT, due to the information it provides about left ventricular function, predicts the prognosis of patients after coronary revascularization.

A prospective comparison of echocardiographic wall motion score index and radionuclide ejection fraction in predicting outcome following acute myocardial infarction

OBJECTIVE

To characterise echocardiographic wall motion score index (WMSI) as a surrogate measure of left ventricular ejection fraction (EF) following acute myocardial infarction (AMI) and to compare its prognostic value with that of EF measured by radionuclide ventriculography (RNV).

DESIGN

A prospective study to compare baseline echocardiographic WMSI with RNV EF in consecutive patients thrombolysed for AMI, both performed on the same day before discharge, and their relative prognostic values in predicting cardiac events.

SETTING

District general hospital coronary care unit and cardiology department.

PATIENTS

120 consecutive patients free of exclusion criteria thrombolysed for AMI and followed up for a mean (SD) of 13 (10) months.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Correlation coefficients and receiver operating characteristic curve analyses plus cardiac event rates at follow up between RNV EF and echocardiographic WMSI.

RESULTS

WMSI correlated well with RNV EF. The best corresponding WMSIs for EFs 45%, 40%, and 35% were 0.6, 0.8, and 1.1, respectively. There were 42 cardiac events during follow up. Although both RNV EF and WMSI were strong univariate predictors of cardiac events, only WMSI independently predicted outcome in a multivariate model. All three WMSI cut offs significantly predicted events, while an RNV EF cut off of </= 45% v > 45% failed to reach significance.

CONCLUSIONS

Although both RNV and echocardiographic WMSI strongly predicted cardiac outcome, WMSI, a cheaper and more readily available technique, is more discriminatory, especially in cases of mild left ventricular dysfunction following AMI.

Detailed endocardial mapping accurately predicts the transmural extent of myocardial infarction

OBJECTIVES

This study delineates between infarcts varying in transmurality by using endocardial electrophysiologic information obtained during catheter-based mapping.

BACKGROUND

The degree of infarct transmurality extent has previously been linked to patient prognosis and may have significant impact on therapeutic strategies. Catheter-based endocardial mapping may accurately delineate between infarcts differing in the transmural extent of necrotic tissue.

METHODS

Electromechanical mapping was performed in 13 dogs four weeks after left anterior descending coronary artery ligation, enabling three-dimensional reconstruction of the left ventricular chamber. A concomitant reduction in bipolar electrogram amplitude (BEA) and local shortening indicated the infarcted region. In addition, impedance, unipolar electrogram amplitude (UEA) and slew rate (SR) were quantified. Subsequently, the hearts were excised, stained with 2,3,5-triphenyltetrazolium chloride and sliced transversely. The mean transmurality of the necrotic tissue in each slice was determined, and infarcts were divided into <30%, 31% to 60% and 61% to 100% transmurality subtypes to be correlated with the corresponding electrical data.

RESULTS

From the three-dimensional reconstructions, a total of 263 endocardial points were entered for correlation with the degree of transmurality (4.6 +/- 2.4 points from each section). All four indices delineated infarcted tissue. However, BEA (1.9 +/- 0.7 mV, 1.4 +/- 0.7 mV, 0.8 +/- 0.4 mV in the three groups respectively, p < 0.05 between each group) proved superior to SR, which could not differentiate between the second (31% to 60%) and third (61% to 100%) transmurality subgroups, and to UEA and impedance, which could not differentiate between the first (<30%) and second transmurality subgroups.

CONCLUSIONS

The degree of infarct transmurality extent can be derived from the electrical properties of the endocardium obtained via detailed catheter-based mapping in this animal model.

Dynamic cerebral autoregulation is unaffected by aging

BACKGROUND AND PURPOSE

Normal aging is associated with marked changes in the cardiovascular and cerebrovascular systems. Although cerebral autoregulation (CA) is impaired in certain disease states, the effect of age per se on dynamic CA in humans is unknown and the focus of this study.

METHODS

Twenty-seven young subjects (</=40 years) and 27 older subjects (>/=55 years), matched for sex and systolic blood pressure (BP), underwent measurement of cerebral blood flow velocity by transcranial Doppler ultrasound and noninvasive beat-to-beat arterial BP measurement during induced and spontaneous dynamic BP stimuli. A standard dynamic autoregulatory index (ARI) was derived for each spontaneous and induced dynamic BP stimulus to include the step response, as well as cardiac baroreceptor sensitivity (BRS), for the 2 groups.

RESULTS

The mean age of the young group was 29+/-5 years, and that of the older group was 68+/-5 years. Cardiac BRS was reduced in the older group (8. 6+/-4.5 versus 16.9+/-8.8 ms/mm Hg; P:<0.0001). However, no age-related differences were demonstrated in step response plots or in ARI values for any pressor or depressor dynamic BP stimulus (P:=0. 62), with mean ARI values for all stimuli combined being 4.9+/-1.8 for the young group and 5.0+/-2.3 for the older group.

CONCLUSIONS

Although increasing age is associated with a decrease in cardiac BRS, dynamic CA, as assessed by step response analysis as well as cerebral blood flow responses to transient and induced BP stimuli, is unaffected by aging.

Effects of aging on cardiorespiratory responses to brief and intense intermittent exercise in endurance-trained athletes

The aim of this study was to investigate the effects of aging on athletes' cardiorespiratory responses to a brief intense intermittent effort, using the force-velocity test as an exercise model. Twelve young athletes (24.8 +/- 1.3 years) and twelve master athletes (65.1 +/- 1.2 years) with similar heights, body masses, and endurance training schedules participated in this study. They performed both a maximal graded exercise and the force-velocity tests. The force-velocity test consisted of the repetition of 6-second sprints against increasing braking forces with 5-minute recovery periods. None of the subjects presented abnormal electrocardiogram responses to the tests. During the force-velocity test, the heart rate magnitudes of response in all subjects were correlated to the corresponding sprint power output (p < .001), with higher values for the young athletes (p < .001). Both groups had similar systolic blood pressure peaks of response during the force-velocity test. Both groups had similar preexercise and end-of-recovery oxygen consumption (VO2), but the young athletes had higher peaks of response (p < .001). The VO2 magnitudes of response increased during the test (p < .01) in all subjects, with higher values for the young athletes (p < .001). There was a positive correlation between the VO2 magnitude of response and (1) the corresponding sprint power output (R = .58,p < .001) and (2) the corresponding number of sprint repetitions (R = .29, p < .02). The young athletes had higher end-of-recovery and peak carbon dioxide production (VCO2) responses than the master athletes (p < .001). Pulmonary ventilation (V(E)) peaks of response to the sprints were higher in the young athletes (p < .001). There was a positive relation between the V(E) and VCO2 peaks of response (R = 84,p < .001). In both groups the peak heart rate, VO2, VCO2, and V(E) values attained during the force-velocity test represented similar percentages of the maximal values reached at exhaustion of maximal graded exercise. These results showed that aging does not alter the percentage of the cardiorespiratory response to a brief intense intermittent exercise such as the force-velocity test. Moreover, the arterial blood pressure response is not significantly altered, whereas the vasodilatatory response is.

Prognostic usefulness of repeated echocardiographic evaluation after acute myocardial infarction. TRACE Study Group. TRAndolapril Cardiac Evaluation

The prognostic value of repeated echocardiographic measurement of left ventricular function after acute myocardial infarction was evaluated. We found that repeated measurements of wall motion index in survivors of acute myocardial infarction, with no reinfarction, provide important prognostic information about death and worsening of heart failure.

Changes in absolute and relative importance in the prognostic value of left ventricular systolic function and congestive heart failure after acute myocardial infarction. TRACE Study Group. Trandolapril Cardiac Evaluation

Changes in the importance of left ventricular (LV) systolic dysfunction and congestive heart failure (CHF) with time after an acute myocardial infarction (AMI) after the introduction of thrombolytic therapy have not been studied. LV systolic function, measured as wall motion index (WMI) by echocardiography, was assessed in 6,676 consecutive patients with an enzyme-confirmed AMI. So that changes in the prognostic value of WMI or CHF could be studied, separate analyses were performed at selected time periods. Average monthly mortality (deaths per 100 patients per month) was determined from life-table analyses, with groups divided by WMI above and below 1.2 (a WMI > 1.2 corresponds to an ejection fraction > 0.35) or by presence and/or absence of CHF. Relative risk (95% confidence intervals [CI]) was determined by proportional hazard models, including baseline characteristics. In patients with LV dysfunction or CHF, monthly mortality was high during the first month (18.3 +/- 1.6% and 20.2 +/- 1.6%, respectively), decreased during the first year, and was stable thereafter (0.8 +/- 0.1% and 1.0 +/- 0.1%, respectively, average monthly mortality after year 3). The relative risk of LV dysfunction decreased from 2.4 (CI 2.0 to 2.9) to 1.3 (CI 1.0 to 1.6) in the same period. The relative risk of CHF decreased from 2.9 (CI 2.3 to 3.8) to 1.6 (CI 1.3 to 2.0). In patients without LV dysfunction or CHF, monthly mortality was relatively high during the first month (5.2% +/- 0.7% and 3.4% +/- 0.6%, respectively) but decreased within the first year to low, stable values (0.6% +/- 0.1% and 0.4% +/- 0.1%, respectively, average monthly mortality after year 3). In patients who received thrombolytic therapy, the relative risk associated with a WMI < or = 1.2 decreased from 3.0 (CI 2.0 to 4.4) to 1.3 (CI 0.9 to 1.6) and from 3.2 (CI 2.0 to 5.1) to 1.7 (CI 1.2 to 2.4) in patients with CHF. The risk of dying decreases steeply with time after an AMI with or without LV dysfunction or CHF and stabilizes at low values after 1 year. This is in contrast to the relative importance of these risk factors, which is maintained for > or = 5 years but decreases with time.

Low dose dobutamine echocardiography is more predictive of reversible dysfunction after acute myocardial infarction than resting single photon emission computed tomographic thallium-201 scintigraphy

To directly compare dobutamine echocardiography and resting single photon emission computed tomographic (SPECT) thallium-201 (Tl-201) scintigraphy for the detection of reversible dysfunction, 64 patients underwent dobutomine echocardiography (baseline, low dose 5 and 10 mg/kg/min, and peak dose), rest Tl-201 scintigraphy (3 mCi - 15 minute and 3- to 4-hour SPECT imaging), and coronary angiography during the first week after acute myocardial infarction. Follow-up echocardiography was performed 4 to 8 weeks after discharge. Wall thickening improved at follow-up in 52% (207 of 399) of the dysfunctional segments. By receiver operating characteristic analysis, biphasic responses and sustained improvement during dobutamine echocardiography were more accurate (p < 0.01) than Tl-201 uptake by SPECT scintigraphy for reversible dysfunction. The greater accuracy of dobutamine echocardiography resulted from higher accuracy in akinetic segments, Q wave infarction, and multivessel coronary artery disease. In conclusion, dobutamine echocardiography was more accurate than resting SPECT Tl-201 scintigraphy for reversible dysfunction after acute myocardial infarction.

Use of left ventricular ejection fraction or wall-motion score index in predicting arrhythmic death in patients following an acute myocardial infarction. The TRACE Study Group

All-cause mortality and morbidity following an acute myocardial infarction (AMI) are correlated to LV systolic dysfunction. The correlation is closest with mortality and morbidity associated with congestive heart failure (CHF). Prediction of arrhythmic death in patients with AMI relies on the correlation between arrhythmic death and "sudden unexpected death" defined as death within 1 hour of onset of new symptoms. Assessment of late potentials, heart rate variability (HRV), T wave alternans, arrhythmias seen on Holter monitoring or during exercise testing, electrophysiological testing, and baroreceptor assessment have all proven to be useful in the prediction of sudden death even when LV systolic function is known. In selected populations HRV is superior to LV systolic function assessment in predicting sudden death and/or arrhythmic events, and may even predict all-cause mortality with the same precision. Comparisons of other methods with LV function assessment should be interpreted with care because most methods have been evaluated in subgroups of infarct patients with a low risk of death. Results from a large series of high risk patients with AMI (the TRAndolapril Cardiac Evaluation study) have shown that even in patients with severe depressed LV systolic function around one-third of the patients will die suddenly. The current situation is that LV function appears to be the best method of predicting death whereas other methods appear very promising for detecting arrhythmic death in more selected populations. The optimal method for selecting patients at high risk of arrhythmic death has not yet been developed, but a combination of LV function and another method, i.e., HRV, appears promising. This may ensure that the enrolled patients have an increased risk of death and that this risk will be due to arrhythmic events. Patients with LVEF of 10% or less can be excluded as they will most likely not die suddenly.

Effects of an 18 week walking programme on cardiac function in previously sedentary or relatively inactive adults

OBJECTIVE

To investigate the effects of an 18 week walking programme upon cardiac function.

METHODS

29 sedentary or relatively inactive but otherwise healthy subjects (15 walkers and 14 controls, aged 40-68 years) completed the study. The walkers completed a progressive 18 week walking programme which required an estimated average energy expenditure of 900 kcal week-1 for the total duration of the study and 1161 kcal week-1 during the final six weeks. Walking was carried out at an intensity of 67.8 (SD 4.99)% of maximum oxygen consumption and 73.8(6.99%) of maximum heart rate. Before and after the intervention all subjects underwent an M mode echocardiogram, graded treadmill walking test, and step test for the assessment of aerobic fitness.

RESULTS

After 18 weeks the results of the control group showed no change in any of the variables measured while the walkers showed a statistically significant increase in the velocity of relaxation of the longitudinal myocardial fibres of the left ventricle and a decrease in heart rate measured during the step tests, indicating an improvement in aerobic capacity.

CONCLUSIONS

Walking promotes improvements in cardiovascular fitness. Moderate forms of exercise may improve cardiac function.

Senescent heart compared with pressure overload-induced hypertrophy

Although systolic left ventricular (LV) function is normal in the elderly, aging is associated in rat papillary muscle with mechanical and sarcoplasmic reticulum Ca2+ ATPase alterations similar to those observed in the hypertrophied heart. However, alterations in the other calcium-regulating proteins implicated in contraction and relaxation are still unknown. To investigate alterations in LV function and calcium-regulating proteins, we measured hemodynamics and Na(+)-Ca2+ exchanger (NCx), ryanodine receptor (RyR2), and sarcoplasmic reticular Ca2+ ATPase (SERCA2) mRNA levels (expressed in densitometric scores normalized to that of poly(A+) mRNA) in left ventricle from 4-month-old (adult, n = 13) and 24-month-old (senescent, n = 15) rats. For ex vivo contractile function, active tension was measured during isolated heart perfusion in adult (n = 11) and senescent (n = 11) rats. For comparison of age-dependent effects of moderate hypertension on both hemodynamics and calcium proteins, renovascular hypertension was induced or a sham operation performed at 2 (n = 11 and n = 6) and 22 (n = 26 and n = 5) months of age. In senescent rats, LV systolic pressure and maximal rates of pressure development were unaltered, although active tension was depressed (4.7 +/- 0.4 versus 8.3 +/- 0.7 g/g heart weight in adults, P < .0001). SERCA2 mRNA levels were decreased in senescent left ventricle (0.98 +/- 0.05 versus 1.18 +/- 0.05 in adults, P < .01), without changes in NCx and RyR2 mRNA accumulation. Renovascular hypertension resulted in 100% mortality in aged rats; in adults, renovascular hypertension resulted, 2 months later, in an increase of LV systolic pressure (170 +/- 7 versus 145 +/- 3 mm Hg in sham-operated rats, P < .05) and in mild LV hypertrophy (+18%, P < .01) associated with a decrease in SERCA2 mRNA levels (1.02 +/- 0.03 versus 1.18 +/- 0.03 in sham-operated rats, P < .001). Contractile dysfunction in senescent isolated heart and decreased SERCA2 mRNA levels were associated with in vivo normal LV function at rest, indicating the existence of in vivo compensatory mechanisms. RyR2 and NCx gene expressions were not implicated in the observed contractile dysfunction. In aged rats, renovascular hypertension resulted in 100% mortality, probably related to elevated levels of circulating angiotensin II, whereas in adult rats, renovascular hypertension induced a mild LV hypertrophy associated with a selective alteration in SERCA2 gene expression.

Importance of congestive heart failure and interaction of congestive heart failure and left ventricular systolic function on prognosis in patients with acute myocardial infarction

Left ventricular (LV) systolic function and congestive heart failure (CHF) are important predictors of long-term mortality after acute myocardial infarction. The importance of transient CHF and the interaction of CHF and LV function on prognosis has not been studied in detail previously. In the TRAndolapril Cardiac Evaluation Study, 6,676 consecutive patients with acute myocardial infarction 1 to 6 days earlier had LV systolic function quantified as wall motion index (echocardiography), which is closely correlated to LV ejection fraction. To study the interaction of CHF and wall motion index on long-term mortality, separate analyses were performed in patients with different levels of LV function. Risk ratio (95% confidence intervals [CI]) were determined from proportional hazard models subgrouped by wall motion index or CHF adjusted for age and gender. Heart failure was separated into transient or persistent. Wall motion index and CHF are correlated. Furthermore, there is an interaction between wall motion index and CHF. The prognostic importance of wall motion index depends on whether patients have CHF or not: the risk ratio associated with decreasing 1 wall motion index unit is 3.0 (2.6 to 3.4) in patients with CHF, and 2.2 (1.7 to 2.9) in patients without CHF when adjusted for age and gender. Similarly, the prognostic importance of CHF depends on the level of wall motion index: the risk ratio associated with CHF is 3.9 (1.8 to 8.3) when the wall motion index is <0.8 and 1.9 (1.5 to 2.3) when the wall motion index is >1.6. Transient CHF is an independent risk factor (risk ratio 1.5, confidence interval [CI] 1.3 to 1.8) although milder than persistent CHF (risk ratio 2.8, CI 2.5 to 3.2).

How well can the chest radiograph diagnose left ventricular dysfunction?

OBJECTIVES

To review the diagnostic utility of the chest radiograph for left ventricular dysfunction.

DATA SOURCES

Structured MEDLINE searches, citation reviews of relevant primary research, review articles, and textbooks, personal files, and data from experts.

STUDY SELECTION

Studies of patients without valvular disease that allowed calculation of the sensitivity and specificity of selected radiographic signs compared with a criterion standard of increased left ventricular preload or reduced ejection fraction.

DATA EXTRACTION

Two independent readers reviewed 29 studies. Studies were pooled after stratification by radiographic finding, criterion standard, and clinical setting.

MAIN RESULTS

Redistribution best diagnosed increased preload with a sensitivity of 65% (95% confidence interval [CI] 55%, 75%) and specificity 67% (95% CI 53%, 79%). Cardiomegaly best diagnosed decreased ejection fraction with a sensitivity of of 51% (95% CI 43%, 60%) and specificity of 79% (95% CI 71%, 85%). Interrater reliability was fair to moderate for redistribution and moderate for cardiomegaly. The clinical setting affected results by decreasing the specificity of cardiomegaly to 8% in detecting increased preload in patients with severe systolic dysfunction. The absence of redistribution could only exclude increased preload in situations in which the suspicion (pretest probability) of disease was less than 9%, whereas redistribution could confirm increased preload when the pretest probability was greater than 91%. The absence of cardiomegaly could only exclude a reduced ejection fraction if the pretest probability was less than 8%, whereas cardiomegaly could confirm a reduced ejection fraction if the pretest probability was greater than 87%.

CONCLUSIONS

Redistribution and cardiomegaly are the best chest radiographic findings for diagnosing increased preload and reduced ejection fraction, respectively. Unfortunately, neither finding alone can adequately exclude or confirm left ventricular dysfunction in usual clinical settings. Redistribution is not always reliably interpreted.

Influence of age on the prognostic importance of left ventricular dysfunction and congestive heart failure on long-term survival after acute myocardial infarction. TRACE Study Group

The aim of this study was to assess the importance of congestive heart failure and left ventricular (LV) systolic dysfunction after an acute myocardial infarction (AIM) on long-term mortality in different age groups. A total of 7,001 consecutive enzyme-confirmed AMIs (6,676 patients) were screened for entry into the TRAndolapril Cardiac Evaluation (TRACE) study. Medical history, echocardiographic estimation of LV systolic function determined as wall motion index, infarct complications, and survival were documented for all patients. To study the importance of congestive heart failure and wall motion index independent of age, we performed Cox proportional-hazard models in 4 different age strata (< or = 55 years, 56 to 65 years, 66 to 75 years, and > 75 years). Patients in these strata had 1-year mortality rates of 5%, 11%, 21%, and 32%, respectively. Three-year mortality rates were 11%, 20%, 34%, and 55%, respectively. The risk ratios (and 95% confidence limits) associated with congestive heart failure in the same 4 age strata were 1.9 (1.3 to 2.9), 2.8 (2.1 to 3.7), 1.8 (1.5 to 2.2) and 1.8 (1.5 to 2.2), respectively. The risk ratios associated with decreasing wall motion index were 6.5 (3.6 to 11.4), 3.3 (2.3 to 4.6), 2.7 (2.2 to 3.4), and 2.1 (1.7 to 2.6), respectively. In absolute percentages, there was an excess 3-year mortality associated with congestive heart failure in the 4 age strata of 14%, 24%, 25%, and 28% respectively. The absolute excess in 3-year mortality associated with LV systolic dysfunction in the 4 age strata was 15%, 19%, 25%, and 21%, respectively. Thus, the relative importance of LV systolic dysfunction and congestive heart failure diminished with increasing age. However, the absolute excess mortality associated with congestive heart failure and LV systolic dysfunction was more pronounced in the elderly than in the young.

Prognostic value of predischarge exercise testing, ejection fraction, and ventricular ectopic activity in acute myocardial infarction treated with streptokinase

The relative importance of prognostic parameters that delineate left ventricular function, myocardial ischemia, and arrhythmogenic potential after thrombolytic therapy is not clear. This study investigated 112 patients with acute myocardial infarction who were treated with thrombolysis to determine the relative prognostic value of predischarge treadmill exercise testing, radionuclide ventriculography, and ambulatory electrocardiographic monitoring for ventricular ectopic activity. During a mean follow-up period of 18 months (range 6 to 30), 42 first cardiac events were recorded, consisting of 3 deaths, 6 reinfarctions, 16 bouts of unstable angina, 16 episodes of heart failure, and 1 arrhythmic event. Univariate analysis revealed ejection fraction, exercise time, and ventricular ectopic count of > or = 10/hour to be predictive of future cardiac events. Subsequent multivariate analysis showed ejection fraction (p <0.001) and exercise time (p=0.002 to have independent prognostic value, but ventricular ectopic activity did not provide additional information. Ventricular ectopic count > or = 10/hour was additionally predictive only when combined with either ejection fraction (R2=5.4%) or exercise time (R2=2.9%). Event-free survival analysis revealed hazard ratios for ejection fraction <40% and exercise time <7 minutes of 3.63 (p=0.001) and 2.16 (p=0.01), respectively. Although ejection fraction and exercise time were able to predict future episodes of heart failure, neither could adequately identify patients at risk of recurrent ischemic events.

Infarct size after acute myocardial infarction measured by quantitative tomographic 99mTc sestamibi imaging predicts subsequent mortality

BACKGROUND

99mTc sestamibi is a recently developed radioisotope that has been used to measure myocardium at risk and infarct size. The relation between these measurements and subsequent patient outcome has not yet been demonstrated.

METHODS AND RESULTS

Two hundred seventy-four consecutive patients with acute myocardial infarction underwent tomographic 99mTc sestamibi imaging on arrival at the hospital (to measure myocardium at risk before reperfusion therapy) and at hospital discharge (to measure the amount of salvaged myocardium and final infarct size). Defect size on the sestamibi images was quantified using a threshold value of 60% of peak counts from the circumferential count profile curves generated for five representative slices of the left ventricle. Patients were followed after hospital discharge to evaluate the association between final infarct size and subsequent mortality. The median defect size measured was 27% of the left ventricle at presentation to the hospital (range, 0% to 77%) and was 12% of the left ventricle at hospital discharge (range, 0% to 68%). Almost one half of the patients had a final infarct size of < or = 10%. The median amount of myocardium salvaged was 9% (range, -31% to 75%). During a median duration of follow-up of 12 months, there were 10 deaths (7 cardiac and 3 noncardiac) and 1 resuscitated out-of-hospital cardiac arrest. There was a significant association between infarct size and overall mortality (chi 2 = 8.66, P = .003) and cardiac mortality (chi 2 = 11.89, P < .001). Two-year mortality was 7% for patients whose infarct size was > or = 12% versus 0% for patients whose infarct size was < 12%. There also was a significant association between myocardium at risk and cardiac mortality (chi 2 = 6.87, P = .009). There was no association between myocardium at risk and overall mortality or between amount of myocardium salvaged and either overall mortality or cardiac mortality.

CONCLUSIONS

Larger infarct size measured by 99mTc sestamibi imaging after acute myocardial infarction is associated with increased mortality risk during short-term follow-up.

Cardiovascular changes by long-term inhibition of the renin-angiotensin system in aging

We studied four groups of 20 female mice to evaluate the long-term effect of an angiotensin-converting enzyme on myocardium and vessels during the natural process of aging. Three groups received enalapril in water from weaning to 24 months of age (group A, 20 mg/L; group B, 10 mg/L; group C, 5 mg/L); group D served as a control. Animals surviving after 24 months were killed, and morphometric studies were performed. Total corporal weight was higher in animals receiving enalapril. Cardiac weight relative to total body weight was lower in the treated groups than in the control group. Cardiac morphometric studies showed lower myocardiosclerosis in animals receiving angiotensin-converting enzyme inhibitor (groups A through D, respectively, 0.9 +/- 0.6%, 1.1 +/- 0.2%, 1.03 +/- 0.1%, and 9.5 +/- 4.3%; P < .01, groups A, B, and C versus D). The number of mitochondria per myocardiocyte was higher in the groups receiving enalapril (A through D, respectively, 85 +/- 7, 85 +/- 6, 83 +/- 8, and 58 +/- 8; P < .01, groups A, B, and C versus D). At the vascular level, vessel diameters were not significantly different between the groups receiving angiotensin-converting enzyme inhibitor and the control group, whereas differences were seen in arterial tunica media thickness (wall-lumen ratio) (groups A through D, respectively, aorta: 0.13 +/- 0.02, 0.11 +/- 0.02, 0.12 +/- 0.01, 2.81 +/- 0.35; intrapulmonary: 0.9 +/- 0.43, 0.6 +/- 0.41, 0.8 +/- 0.46, 1.9 +/- 0.51; intracerebral: 2.18 +/- 0.46, 2.29 +/- 0.45, 2.46 +/- 0.43, 3.30 +/- 0.41; intrarenal: 2.28 +/- 0.46, 2.73 +/- 0.48, 2.70 +/- 0.51, 3.23 +/- 0.41; intracariaciac: 2.27 +/- 0.44, 2.59 +/- 0.41, 2.80 +/- 0.43, 3.68 +/- 0.47; P < .001, groups A, B, and C versus D).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic left ventricular systolic function and volumes in young adults: distribution and factors influencing variability

Low left ventricular ejection fraction (LVEF), a measure of global systolic left ventricular dysfunction, is associated with an increased risk of recurrent coronary events or death in persons with cardiac disease. There are few data on the distribution of resting LVEF and component volumes in healthy young adults or on any association of LVEF with coronary risk factors. LVEF and left ventricular end-diastolic and end-systolic volumes (LVEDV and LVESV, respectively) were measured by two-dimensional echocardiography in 1782 men and women 23 to 35 years old without self-reported heart disease (other than mitral valve prolapse, n = 53) who were participants in the multicenter Coronary Artery Risk Development in Young Adults study. Factors analyzed as potential contributors to LVEF, LVEDV, and LVESV included age, gender, race, blood pressure, alcohol use, current smoking, family history of myocardial infarction, total and high-density lipoprotein cholesterol concentrations, obesity, reported physical activity, and fitness as assessed by treadmill exercise testing. LVEF was lower in men (mean 62.6% SD 5.7%) than in women (mean 63.9%, SD 5.7%) (p < 0.01) but did not differ significantly between black and white subjects. Ninety percent of subjects had an LVEF between 53% and 71%. LVEDV and LVESV were > 25% greater in men than in women. From multivariate analysis, male gender, history of hypertension, and current smoking were each positively and independently associated with an approximately 1% lower LVEF. Body surface area, a family history of premature myocardial infarction, and treadmill workload 150 time were positively related, whereas total skinfold thickness was negatively related to LVEDV and LVESV.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic assessment in coronary artery disease: role of radionuclide angiography

Left ventricular function is one of the most important determinants, if not the most important determinant, of outcome in patients with coronary artery disease. The ability of radionuclide angiography to assess resting and exercise ejection fraction accurately and reproducibly has been shown to be a critical determinant of survival in large-scale studies of survivors of myocardial infarction, as well as patients with chronic stable angina. In addition, several centers have demonstrated that the exercise ejection fraction is an extremely valuable (and perhaps the most valuable) noninvasive parameter in predicting survival among patients with coronary artery disease. The prognostic insights gained from the exercise ejection fraction add incremental predictive information to the coronary anatomic information obtained from coronary arteriography, especially in patients with multivessel disease and those with left ventricular dysfunction at rest.

Prognostic value of adenosine single-photon emission computed tomographic thallium imaging in medically treated patients with angiographic evidence of coronary artery disease

BACKGROUND

This study examined the prognostic value of adenosine single-photon emission computed tomographic thallium imaging in medically treated patients with angiographic evidence of coronary artery disease (CAD).

METHODS AND RESULTS

Patients who underwent coronary revascularization within 3 months of this study were excluded. There were 177 patients aged 64 +/- 11 years; 74 had one-vessel, 57 had two-vessel, and 46 had three-vessel CAD (> or = 50% diameter stenosis). During a mean follow-up of 22 +/- 13 months, there were 14 events (cardiac death or nonfatal myocardial infarction). Cox survival analysis with important clinical, catheterization, and scintigraphic variables identified the size of perfusion abnormality as the strongest predictor of events (chi 2 = 9). Life-table analysis showed that patients with perfusion defects of 15% or greater of the myocardium had a worse prognosis than had patients with no or smaller defects (Mantel-Cox statistic = 13; p < 0.001).

CONCLUSIONS

Thus adenosine single-photo emission computed tomographic thallium imaging provides important prognostic data in medically treated patients with CAD. The extent of thallium abnormality is the most important predictor of events.

Preexisting cardiovascular conditions and long-term prognosis after initial myocardial infarction: the Framingham Study

Preexisting cardiovascular conditions (angina pectoris, intermittent claudication, stroke or transient ischemic attack, and congestive heart failure) were evaluated in relation to long-term prognosis after an initial MI in 828 subjects from the Framingham Heart Study. Preexisting angina pectoris and intermittent claudication in men were associated with increased risk of coronary mortality and recurrent MI, whereas congestive heart failure increased coronary mortality. In women, prior angina pectoris increased the risk of recurrent MI and congestive heart failure increased the coronary mortality. Adjusting for the major cardiovascular risk factors measured before MI, these results held for men but no significant adverse effects persisted in women. Among subjects who survived to return for subsequent examinations, only prior congestive heart failure in men increased the risk after adjusting for post-MI risk factors. In women who returned, angina pectoris and intermittent claudication were associated with poor post-MI prognosis. These results suggest that atherosclerosis is a diffuse disease of the circulatory system, and one in which post-MI prognosis is influenced by the presence of other preexisting cardiovascular conditions. Hence a patient who has an MI after prior expression of cardiovascular disease requires more vigorous preventive management.

Sensitivity and specificity of echocardiographic identification of patients eligible for safe early discharge after acute myocardial infarction

In a prospective clinical trial of 195 consecutive unselected patients with acute myocardial infarction (AMI), systematic blinded clinical and echocardiographic examinations were performed by two observers on day 5. The purpose was to define low-risk patients with regard to in-hospital and 2-month mortality and predict the potential costs (lost patient lives) and benefits (saved in-patient days) if as a routine procedure these low-risk patients were discharged earlier. By design, low-risk patients as defined by clinical criteria were allocated to discharge on days 7 to 10 and by echocardiographic criteria on days 5 to 7 after AMI. The sensitivity of the echocardiographic low-risk identification procedure was more than twofold higher than the sensitivity of clinical low-risk identification (49% vs 24%). Both procedures were safe with a specificity of 100% for cardiac mortality. Optimal identification of low-risk patients was provided by combining data from echocardiographic and clinical evaluations (sensitivity 59%). Results of the study suggest that a bedside echocardiographic approach to estimation of global left ventricular function is more sensitive and equally specific and therefore more efficient for risk stratification on post-AMI day 5 than clinical examination alone. Thus echocardiographic examination allows identification of a larger subset of patients with AMI (greater than 40% of the population alive on day 5) who can be discharged earlier and safely, with a potential saving of in-patient days of 436 days in 87 low-risk patients minus the cost of echocardiographic studies in 195 patients. However, the best prediction was obtained by combining clinical and echocardiographic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of exercise stress test, radionuclide angiography and coronary angiography in predicting new coronary events in asymptomatic patients after a first episode of myocardial infarction

One-hundred-and-fifty-five consecutive symptom-free patients underwent maximal treadmill exercise testing, rest and stress radionuclide angiography at least two months after an uncomplicated acute myocardial infarction; of these, 90 underwent coronary angiography. All patients were followed-up for a mean of 32 +/- 13 months regarding the prediction of hard (death and reinfarction) and soft (angina and coronary surgery) coronary events. The specificity, sensitivity, positive and negative predictive value of exercise stress test were 47%, 76% and 41% for any coronary events; none of the patients who incurred a hard coronary event showed ischemia during electrocardiographic exercise tests. Sensitivity, specificity and positive predictive value for failure to increase the ejection fraction of at least 5% were 60%, 45% and 30% for any coronary event and 25%, 49% and 2% for any hard coronary event. The presence of multivessel disease at coronary angiography showed a sensitivity of 62% for any coronary event and of 67% for hard coronary events; specificities were 66% and 57%, and predictive values were 52% and 10%, respectively. It is concluded that electrocardiographic exercise testing, radionuclide angiography and coronary angiography are not helpful two months after an episode of uncomplicated myocardial infarction in order to identify patients who will suffer a new coronary event.

Echocardiographic design of a multicenter investigation of free-living elderly subjects: the Cardiovascular Health Study

The Framingham study has shown by M-mode echocardiography that left ventricular hypertrophy is a powerful, independent predictor for the development of coronary heart disease and that increased left atrial dimension has been associated with an increased risk of stroke. No previous population-based study has evaluated the risk factor correlates and predictive value for coronary heart disease and stroke of two-dimensional and Doppler, as well as M-mode, echocardiography. The Cardiovascular Health Study is a multi-year prospective epidemiologic study of 5201 men and women older than 65 recruited from four geographic sites in the United States. The main objectives of incorporating echocardiography were to determine whether echocardiographic indices, or changes in these indices, are (1) correlated with traditional risk factors for coronary heart disease and stroke; and (2) independent predictors of morbidity and mortality for coronary heart disease and stroke. Echocardiographic measurements of interest include those related to global and segmental left ventricular systolic and diastolic structure and function and left atrial size. For each subject, a baseline echocardiogram was recorded in super-VHS tape using a standard protocol and equipment. All studies were sent to a reading center where images were digitized and measurements were made using customized computer algorithms. Calculated data and images were stored on optical disks to facilitate retrieval and future comparisons in longitudinal studies. A second echocardiogram is scheduled in year 7, with a goal of determining whether changes in cardiac anatomy or function over a 5-year period are important predictors of morbidity or mortality from coronary heart disease and stroke. Quality control measures included standardized training of echocardiography technicians and readers, technician observation by a trained echocardiographer, periodic blind duplicate readings with reader review sessions, phantom studies, and quality control adults.

Uncomplicated first myocardial infarction: strategy for comprehensive prognostic studies

To evaluate the prognostic role of combined cardiac studies (submaximal exercise test, thallium-201 scintigraphy, radionuclide exercise ventriculography, two-dimensional echocardiography, Holter monitoring and cardiac catheterization) in patients with a first acute myocardial infarction without complications during hospital admission, 115 consecutive patients aged less than 65 years were prospectively evaluated. The studies were carried out before hospital discharge and the patients were then clinically followed up for 12 months. During the follow-up period, 69 patients (60%) developed complications, which were severe in 23 (20%). Half of all complications and 70% of severe complications developed during the 1st follow-up month. Logistic regression analysis disclosed that the combination of studies with the highest predictive power for complications (probability of complications 99%) and severe complications (probability of severe complications 95%) was the association of exercise test + thallium-201 + echocardiogram. Four decision models (exercise test + echocardiography, exercise test + radionuclide ventriculography, thallium-201 scintigraphy + echocardiography, thallium-201 scintigraphy + radionuclide ventriculography) allowed the stratification of all patients in a particular risk category (high, intermediate or low). The best decision model was the association of thallium-201 scintigraphy + radionuclide ventriculography (probability of complications if both tests were positive 84%; probability of absence of severe complications if both tests were negative 88%), but there were no significant differences with the other models. Any association of a test detecting residual ischemia or functional capacity, or both (exercise test or thallium-201) and a test assessing ventricular function (echocardiography or radionuclide ventriculography) results in significant prognostic information in patients with an uncomplicated first acute myocardial infarction. Additional cardiac catheterization does not improve the predictive power of noninvasive studies, which should ideally be performed before hospital discharge because most complications develop during the 1st follow-up month.

Effect of left ventricular aneurysm on risk of sudden and nonsudden cardiac death

Although left ventricular (LV) aneurysm is associated with increased mortality, its independent prognostic significance is controversial. To determine the effect of LV aneurysm on risk, 121 patients with healed myocardial infarction (MI), 55 manifesting akinesia on ventriculography (MI group) and 66 with LV aneurysm characterized by diastolic deformity (eccentricity) and systolic dyskinesia (LV aneurysm group) were studied. At a mean follow-up of 5.7 years, there were 32 cardiac deaths (12 MI vs 20 LV aneurysm), including 9 sudden deaths (1 MI vs 8 LV aneurysm). Multivariate analysis revealed decreasing ejection fraction to be the best predictor of total cardiac death, and revascularization to be protective. Nonsudden cardiac death was predicted by ejection fraction, absence of revascularization and right coronary artery disease, whereas sudden cardiac death was predicted by LV aneurysm and the frequency of ventricular ectopic complexes on Holter monitoring. In the MI group, ejection fraction was the only significant predictor of total cardiac death and nonsudden cardiac death. In the LV aneurysm group, total cardiac death, as well as nonsudden cardiac death, were predicted by ejection fraction, ventricular tachycardia and right coronary artery disease, whereas ventricular tachycardia predicted sudden cardiac death. It is concluded that the risk profile for total cardiac death differs between LV aneurysm and MI patients, and that LV aneurysm constitutes an independent predictor of late sudden cardiac death after MI. Moreover, on a substrate of LV aneurysm, the risk factors for sudden cardiac death and nonsudden cardiac death differ, with ventricular tachycardia being the sole predictor of sudden cardiac death. Furthermore, Holter monitoring is valuable in identifying patients at persistent risk of sudden cardiac death.

Prognostic value of radionuclide angiography in medically treated patients with coronary artery disease. A comparison with clinical and catheterization variables

To evaluate the usefulness of multiple measures from rest and exercise radionuclide angiography (RNA) in predicting cardiovascular death and cardiovascular events (death or nonfatal myocardial infarction) and to assess the prognostic usefulness of the RNA relative to clinical and catheterization data, we studied 571 stable patients with symptomatic coronary artery disease who had upright rest/exercise first-pass RNA within 3 months of catheterization and were medically treated. With a median follow-up of 5.4 years, 90 patients have died from cardiovascular causes, and 147 patients have either died or suffered a nonfatal myocardial infarction. Using the Cox regression model and a preselected group of RNA variables, the most important RNA predictor of mortality was exercise ejection fraction (chi 2 = 81, p less than 0.00001). Neither rest ejection fraction nor the change in ejection fraction from rest to exercise contributed additional predictive information. Two other RNA study variables, the change in heart rate from rest to exercise and rest end-diastolic volume index, did contribute additional prognostic information to the exercise ejection fraction (chi 2 = 23, p less than 0.0001). Compared with noninvasive clinical data (history, physical examination, electrocardiogram, and chest radiograph), RNA variables were considerably more predictive of mortality (chi 2 = 71 [clinical variables] versus chi 2 = 104 [RNA]). Remarkably, the strength of the relation of RNA variables with mortality was equivalent to that of the set of catheterization variables previously demonstrated in our large angiographic population to be prognostically important (chi 2 = 104 [RNA] versus chi 2 = 102 [catheterization variables]). The RNA contained 84% of the information provided by clinical and catheterization descriptors combined. Furthermore, the RNA contributed significant additional prognostic information to the clinical and catheterization data (chi 2 = 13.6, p = 0.0035). For cardiovascular events, the relative prognostic usefulness of the RNA was similar, although relations with this outcome were generally weaker. Descriptors from the rest/exercise RNA exhibit a powerful relation with long-term outcomes and can be useful in defining risk, even when clinical and catheterization data are available.

Early estimation of risk by echocardiographic determination of wall motion index in an unselected population with acute myocardial infarction

In a prospective series of 201 consecutive patients with creatine kinase-MB--documented acute myocardial infarction (AMI), postadmittance and predischarge echocardiographic wall motion indexes (WMI) were determined (median 45 hours vs 14 days after AMI). No significant change of left ventricular systolic performance was found between postadmittance and predischarge examinations in 179 survivors (WMI 1.3 +/- 0.4 vs 1.4 +/- 0.4, p greater than 0.05). Hospital mortality was 11% (22 of 201), cumulated 2-month mortality 15% (31 of 201) and cumulated 1-year mortality 26% (52 of 201). Mortality increased rapidly with decreasing left ventricular function as determined by WMI. When early WMI was less than 1.0, 1-year mortality was 51% (28 of 55) versus 8% (7 of 83) when WMI was greater than 1.3 (p less than 0.0001). Ventricular fibrillation (n = 24) and cardiogenic shock (n = 27) carried a much better prognosis when WMI showed good left ventricular function. When WMI was less than 1.0, 1-year mortality was 83% (10 of 12) versus 93% (13 of 14) in ventricular fibrillation and cardiogenic shock, respectively, whereas it was 0% (0 of 4) versus 33% (2 of 6) when WMI was greater than 1.3. In 15% of patients major discrepancies between early Killip class and WMI were noted. WMI showed much smaller fluctuations during the hospital course of AMI than did Killip class and appeared to be a more stable prognostic marker. Large-scale, early risk stratification by echocardiography has now become available and appears to facilitate a rational, individualized discharge policy in the coronary care unit and to provide an improved basis for randomization of patients in controlled studies aimed at tailoring new treatment in AMI.

Limitations of a conventional logistic regression model based on left ventricular ejection fraction in predicting coronary events after myocardial infarction

The clinical utility of conventional logistic regression models based on left ventricular ejection fraction (LVEF) for the prediction of cardiac events (death or recurrent infarction) was assessed in 646 postinfarction patients undergoing radionuclide ventriculography at rest and during exercise. The discriminant power of 2 different models (LVEF at rest alone vs LVEF at rest plus LVEF at peak exercise) was quantified in terms of the area under receiver-operating characteristic curves based on knowledge of patient outcome in the year after testing and the logistic probability of that outcome. Although LVEF at rest provided a significant amount of prognostic information (receiver-operating characteristic curve area = 62 +/- 4%, p less than 0.001), several limitations were observed: (1) powerful predictors of risk were uncommon (32% of patients with an LVEF at rest less than 0.20 had a cardiac event, but only 3% of the population had such extreme values); (2) the accuracy of predictions for high risk patients was less than for low risk patients (28 vs 98%, p less than 0.001); (3) addition of exercise LVEF to the model did not improve the accuracy of prediction (receiver-operating characteristic curve area = 68 +/- 4%, p = 0.11); and (4) predictions for individual patients were very imprecise (the 95% confidence interval of percent risk for an LVEF at rest of 0.20 [11 to 36%] overlapped that for an LVEF at rest of 0.60 [0 to 14%]).(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term and long-term prognosis after myocardial infarction: prognostic value of coronary anatomy and left ventriculography

To assess prospectively short-term (1 year) and long-term (4 years) prognostic variables from heart catheterization, 325 consecutive patients of 65 years or less who survived a myocardial infarction were studied. In all coronary angiography and left ventriculography was performed 4-6 weeks after infarction. First year mortality rate was significantly higher in patients with an ejection fraction less than 0.30 (20%) than in patients with an ejection fraction greater than or equal to 0.30 (2%, P less than 0.001). During 4-year follow-up cumulative mortality was 44% in patients with an ejection fraction less than 0.30 vs 11% in patients with an ejection fraction greater than or equal to 0.30 (P less than 0.001). In patients who survived the first year after infarction, however, a low ejection fraction less than 0.30 was not associated with higher mortality rate during the subsequent 3 years. Mortality in patients with one-, two- or three-vessel disease was equally distributed in the first year. After 4 years patients with three-vessel disease had a significant higher mortality (32%) than patients with two- or one-vessel disease (12 and 11%, respectively; P less than 0.05). Reinfarction rate was higher in patients with an ejection fraction less than 0.30 (14%) than in patients with an ejection fraction greater than or equal to 0.30 (3%, P less than 0.05) in the first year. During 4-year follow-up reinfarction rate was 38% in patients with an ejection fraction less than 0.30 vs. 13% in patients with an ejection fraction greater than or equal to 0.30 (P less than 0.05). Again, in patients who survived the first year without reinfarction, an ejection fraction less than 0.30 had no prognostic value for recurrent myocardial infarction during the subsequent three years. Three-vessel disease had no higher reinfarction rate in the first year of follow-up: during 4 years, patients with three-vessel disease had a reinfarction rate (32%) compared to patients with two- and one-vessel disease (14 and 11%, respectively; P less than 0.05). It is concluded that an ejection fraction less than 0.30 is a major risk factor for cardiac death and reinfarction only in the first year after myocardial infarction. Beyond the first year, a subgroup of patients with three-vessel disease is at risk for both cardiac death and reinfarction during the three subsequent years.

Prediction of left ventricular ejection fraction using a unique method of chest x-ray and ECG analysis: a noninvasive index of cardiac performance based on the concept of heart volume and mass interrelationship

A reasonably accurate, simple, inexpensive, noninvasive method of determining ejection fraction (EF) is necessary to evaluate left ventricular function in epidemiologic studies and individual patients. Using the concepts of left ventricular mass reflected by precordial R wave summation (M) and left ventricular volume (V) estimated by chest roentgenography in 114 patients with myocardial disease undergoing left ventriculography, EF was predicted with the formula: EF = 63.74 - (2.16.V) + (0.34.M); R2 = 0.69; standard error of the estimate (SEE) = 11. Because angiographic inferior wall motion (IWM) abnormalities significantly affected the results, but inferior Q waves were usually only present in patients having one infarct, a noninvasive technique to predict the presence of inferior wall motion abnormality (IMA) in patients having multiple infarcts was developed and based on the relationship of precordial R wave summation (M) and roentgenographic heart volumenometry (V). By combining V, M, and IMA (which predicted IWM) to determine EF, multiple linear regression analysis showed that EF = 67.30 - (1.56.V) + (0.23.M) - (14.18 IMA) (R2 = 0.77; SEE = 9). Prospective validation of the formula was then done in 139 consecutive individuals, with R2 = 0.49 and SEE = 9. This study demonstrates that routinely performed, simple, inexpensive clinical tests provide data that can be combined by multiple regression analysis to predict resting EF in patients with heart disease affecting the left ventricle. This unique method may allow inexpensive ventricular function screening in large population studies and in addition might provide an independent index of myocardial performance for clinical use, since it reflects the amount of contractile mass per unit of left ventricular volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term risk stratification at admission based on simple clinical data in acute myocardial infarction

Simple clinical data, available in all coronary care units, were recorded in 1,013 consecutive patients with acute myocardial infarction (AMI). In order to identify the patients at highest and lowest risk of mortality during hospital stay, a prognostic index was established from a stepwise logistic discriminant analysis of 10 clinical variables obtained at admission in a consecutive series of 477 patients hospitalized in 1 of 2 coronary care units admitting new patients on alternate days and treating them similarly. This prognostic index was applied to a comparison group of 536 consecutive patients admitted to the other coronary care unit. In the experimental group, 57 of the 477 patients (12%) died during hospital stay; 60 of the 536 patients (11%) died in the comparison group. As individual variables, age, previous history of AMI, anterior site and left ventricular function on admission were associated with increased mortality. Three variables were selected from the stepwise logistic discriminant analysis of the experimental group: age; site (anterior = 1, other = 0); and grade of left ventricular function (0 to 4). Prognostic index = 5.9019 - 0.8961 function - 0.5708 location - 0.0369 age. This index was validated in the comparison group. Patients were allocated into different classes with increasing index values associated with decreasing risk. Three subgroups of patients were identified: high risk of hospital mortality (index less than or equal to 1; mortality: 51%), intermediate risk (index 1 to 3; mortality: 18%) and low risk (index greater than 3; mortality: 4%). The use of this simple prognostic index may improve clinical management and selection of patients for intervention trials.

Quantitative radionuclide angiocardiography

Quantitation of cardiac pump function using radionuclide angiocardiography provides objective information for the management of patients with heart disease. Left and right ventricular ejection fraction, stroke volume ratio, ejection rate, diastolic function, ventricular volume, parametric imaging, amplitude and phase analysis, and shunt quantification can be measured from the radionuclide angiocardiogram at rest, during exercise, and during pharmacologic interventions. This review describes these methods and discusses their reliability and their role in the clinical assessment of patients with cardiac disease.

Relative prognostic value of rest thallium-201 imaging, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring after acute myocardial infarction

Rest thallium-201 scintigraphy, radionuclide ventriculography and 24 hour Holter monitoring are acceptable methods to assess myocardial necrosis, performance and electrical instability. This study examined the relative value of the three tests, when obtained a mean of 7 days after acute myocardial infarction, in predicting 1 year mortality in 93 patients. Planar thallium-201 images were obtained in three projections and were scored on a scale of 0 to 4 in 15 segments (normal score = 60). Patients were classified as having high risk test results as follows: thallium score less than or equal to 45 (33 patients), left ventricular ejection fraction less than or equal to 40% (51 patients) and complex ventricular arrhythmias on Holter monitoring (36 patients). During the follow-up of 6.4 +/- 3.4 months (mean +/- SD), 15 patients died of cardiac causes. All three tests were important predictors of survival by univariate Cox survival analysis; the thallium score, however, was the only important predictor by multivariate analysis. The predictive power of the thallium score was comparable with that of combined ejection fraction and Holter monitoring (chi-square = 21 versus chi-square = 22). Thus, rest thallium-201 imaging performed before hospital discharge provides important prognostic information in survivors of acute myocardial infarction which is comparable with that provided by left ventricular ejection fraction and Holter monitoring. Patients with a lower thallium score (large perfusion defects) are at high risk of cardiac death during the first year after infarction.

The effect of intravenous thrombolytic therapy on left ventricular function: a report on tissue-type plasminogen activator and streptokinase from the Thrombolysis in Myocardial Infarction (TIMI Phase I) trial

In Phase I of the NHLBI trial of Thrombolysis in Myocardial Infarction (TIMI), 290 patients admitted within 7 hr after onset of acute infarction were randomly assigned to intravenous treatment with either streptokinase (SK) or recombinant tissue-type plasminogen activator (rt-PA). Left ventricular function was measured from contrast ventriculograms in 145 patients with both pretreatment and predischarge studies analyzable. Regional wall motion in the infarct site was measured by the centerline method and expressed in units of standard deviations (SDs) from the mean motion in 52 normal subjects. Patients treated with rt-PA (n = 77) achieved a significantly higher reperfusion rate after 90 min of treatment. Perfusion of the infarct-related artery improved from visual grade 0 or 1 (total occlusion or penetration without perfusion) to grade 2 or 3 (partial or full reperfusion) in 62% receiving rt-PA vs 31% receiving SK (n = 68) (p less than .001). However, the ejection fraction did not change significantly from before treatment to before discharge in either treatment group (+0.7 +/- 6.7% vs +1.0 +/- 8.3%, respectively). A small but significant increase in regional wall motion was observed in each of the two groups (+0.4 +/- 0.8 vs +0.3 +/- 0.8 SD/chord, respectively; each p less than .001 compared with baseline). This was countered by declines in the hyperkinesis of the noninfarct region (-0.3 +/- 1.0 SD/chord [p = .01] compared with baseline and -0.2 +/- 1.0 SD/chord [p = .23], respectively). Analysis of the combined groups revealed that the ejection fraction increased only in patients who achieved reperfusion by 90 min after onset of therapy or who had subtotal occlusions initially. There was greater recovery of left ventricular function in patients who achieved reperfusion earlier vs later than 4 hr after symptom onset and in patients with vs without some collateral circulation to the infarct-related artery.

Advantages and applications of the centerline method for characterizing regional ventricular function

We sought to identify theoretical advantages and applications of the centerline method for quantitative assessment of regional ventricular function. Motion was measured along 100 chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours, and normalized for heart size. Abnormality was expressed in units of standard deviations from the mean motion in a normal reference population to indicate both the severity and significance of the wall motion abnormality. The mean abnormality averaged over 100 chords correlated highly with the area ejection fraction (r = .97). The centerline method uses a "sliding window" to measure motion where it is abnormal, because assessment of wall motion in predefined regions of the ventricular contour underestimates abnormality. From the 100 data points, the extent (% of contour) of regional abnormalities can also be determined. The severity of hypokinesis at the site of acute myocardial infarction correlated better with infarct size estimated from creatine kinase release (r = -.78) than did the ejection fraction or the circumferential extent of hypokinesis. Because the centerline method measures motion along locally determined vectors, and requires no apex, origin, coordinate system, or geometric reference figure, it can be applied to contours as dissimilar as the 60 degree left anterior oblique projection of the left ventricle and the 75 degree left anterior oblique projection of the right ventricle.

Simple prediction of 28-day mortality following an acute myocardial infarction

Upon admission to a drug study of 1,122 patients with myocardial infarction, twenty-seven questions relating to the patients' cardiac status were answered by the physicians. These questions were categorized into four groups of related items of signs and symptoms. Thus four scores could be completed: degree of infarction score, cardiogenic shock score, cardiac failure score, and overall-state-of-the-patient score. The scores were all found to be highly correlated with 28-day mortality. Also, since these scores can be easily and immediately determined at the bedside, or with standard tests, they are both convenient and accurate predictors of 28-day mortality following a myocardial infarction.