Left ventricular ejection fraction and first third ejection fraction early after acute myocardial infarction: value for predicting mortality and morbidity

First phase ejection fraction in aortic stenosis: A useful new measure of early left ventricular systolic dysfunction

In aortic stenosis (AS), a left ventricular (LV) ejection fraction (EF) <50% or symptoms are class I indications for aortic valve intervention. However, an EF <50% may be too conservative since subendocardial fibrosis may already have developed. An earlier marker of LV systolic dysfunction is therefore needed and first phase EF (EF1) is a promising new candidate. It is the EF measured over early systole to the point of maximum transaortic blood flow. It may be low in the presence of preserved total LV EF since the heart may compensate by recruiting myosin motors in later systole. The EF1 is inversely related to the grade of AS and directly related to markers of subendocardial fibrosis like late gadolinium enhancement on cardiac magnetic resonance scanning. A reduced EF1 (<25%) predicts adverse clinical events better that total EF and global longitudinal strain. We suggest that it is worth exploring as an indication for surgery in patients with asymptomatic severe AS.

Every minute counts: in-hospital changes of left ventricular regional and global function in patients with ST-segment elevation myocardial infarction

AIMS

The aim of our study was to assess the effects of an early percutaneous coronary intervention on changes of in-hospital left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) in patients with ST-segment elevation myocardial infarction.

METHODS

The study population consisted of 324 consecutive patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention, divided into two groups, according to the first medical contact (FMC)-to-reperfusion time, respectively, 90 min or less (n = 173) and more than 90 min (n = 151). Moreover, we performed a sub-analysis in the group of patients who showed at discharge an improvement in the LVEF of at least 10%.

RESULTS

In both groups at baseline, patients suffered from a moderately reduced LVEF (40.88 ± 8.38% in ≤90 min group vs. 40.70 ± 8.98% in >90 min group; P = 0.858). A WMSI of more than 1 was recorded uniformly: 1.71 ± 0.37 in patients with FMC-to-reperfusion 90 min or less and 1.72 ± 0.38 in patients more than 90 min (P = 0.810). At the time of discharge, a significant improvement in LVEF (43.82 ± 8.38%, P = 0.001) and WMSI (1.60 ± 0.41, P = 0.009) exclusively emerged in the 90 min or less group. Furthermore, we identified 105 patients who experienced an improvement in the LVEF of at least 10% compared with baseline values. In these patients FMC-to-reperfusion and total ischemic time resulted as significantly shorter, when compared with patients with LVEF improvement of less than 10%.

CONCLUSION

Our study confirms and reinforces the concept that reducing the duration of the time between FMC and reperfusion, as well as the total ischemic time influences a positive recovery of left ventricular global and regional function during in-hospital stay.

First-phase ejection fraction: association with remodelling and outcome in aortic valve stenosis

Background

First-phase ejection fraction (EF1), the left ventricular (LV) ejection fraction (EF) until the time of peak transaortic velocity, is a novel marker of subclinical LV dysfunction able to predict adverse events in aortic stenosis (AS). This study investigated the association between end-systolic wall stress (ESWS) and EF1 in severe AS, as well as the prognostic value of EF1 in severe asymptomatic AS.

Methods

Two prospectively gathered cohorts of 94 asymptomatic patients and 108 symptomatic patients scheduled for aortic valve replacement (AVR), all with severe AS (aortic valve area <1 cm²) were stratified according to the median value of EF1 (33%). EF1 was defined as the EF at peak transaortic velocity. Asymptomatic patients were followed up for 3 years for the combined end-point of death, AVR or admission with heart failure.

Results

EF1 correlated with EF and was inversely associated with ESWS. In multivariate regression analysis, ESWS (p<0.001) and replacement fibrosis measured by MRI (p=0.02) were associated with EF1. Among asymptomatic patients, EF1 above the median was associated with the combined primary endpoint (HR=0.53 (95% CI 0.33 to 0.87)), while global longitudinal strain and EF were not. Among 42 patients with discordant AS (mean gradient <40 mm Hg), EF1 above median was associated with the primary endpoint (HR 0.28 (95% CI 0.12 to 0.61)).

Conclusion

EF1 is an afterload-dependent measure that is associated with events in patients with asymptomatic severe AS. The afterload dependency of EF1 may be useful in timing of risk stratification in patients with discordant AS.

Trial registration numbers

NCT02395107 and NCT02316587.

Reduced First-Phase Ejection Fraction and Sustained Myocardial Wall Stress in Hypertensive Patients With Diastolic Dysfunction: A Manifestation of Impaired Shortening Deactivation That Links Systolic to Diastolic Dysfunction and Preserves Systolic Ejection Fraction

Impaired shortening deactivation of cardiac myocytes could sustain myocardial contraction, preserving ejection fraction at the expense of diastolic dysfunction. We examined the relationship between first-phase ejection fraction (EF1), the fraction of left ventricular volume ejected from the start of systole to the time of the first peak in left ventricular pressure (corresponding to the time of maximal ventricular shortening) to the duration of myocardial contraction and diastolic function in patients with hypertension (n=163), and varying degrees of diastolic dysfunction. Left ventricular systolic pressure was estimated by carotid tonometry; time-resolved left ventricular cavity and wall volume were obtained by echocardiography with speckle wall tracking. Measurements were repeated after nitroglycerin, a drug known to influence ventricular dynamics, in a subsample (n=18) of patients. EF1 and time of onset of ventricular relaxation (as determined from the temporal pattern of myocardial wall stress) were independently correlated with diastolic relaxation as measured by tissue Doppler early diastolic mitral annular velocity (E', standardized regression coefficients 0.48 and -0.34 for EF1 and time of onset of ventricular relaxation, respectively, each P<0.001, irrespective of adjustment for age, sex, antihypertensive treatment, measures of afterload, and ventricular geometry) and with diastolic function measured by the ratio of transmitral Doppler early filling velocity (E) to E' (E/E', regression coefficients -0.34 and 0.34, respectively, each P<0.001). Nitroglycerin increased EF1, decreased time of onset of ventricular relaxation, and improved diastolic function (each P<0.05). Hypertensive patients with diastolic dysfunction exhibit reduced EF1 which may sustain myocardial contraction, preserving systolic ejection fraction at the expense of impaired diastolic function.

Prognostic power of global 2D strain according to left ventricular ejection fraction in patients with ST elevation myocardial infarction

Backgrounds

We aimed to evaluate the predictive power of longitudinal and circumferential fibers according to left ventricular ejection fraction (LVEF) in successfully reperfused acute ST elevation myocardial infarction (STEMI) patients.

Methods

Total 691 patients (age 59±13, 20% female) underwent clinical evaluation and conventional and strain echocardiography (Global longitudinal strain (GLS), global circumferential strain (GCS)). The clinical outcome was defined as the composite of death, hospitalization for heart failure, non-fatal myocardial infarction, and ventricular arrhythmia.

Results

During a follow-up of 39±19 months, there were 47 (6.8%) clinical events. In multivariate Cox models adjusted clinical risk factors, age (HR 1.08, p = 0.001) and GLS (HR 1.37, p = 0.001) were independent predictors. The addition of GLS resulted in significant incremental improvement in the predictive value on LVEF (χ² = 31.8→45.8, p<0.001), although GCS offers no additional benefit. In the subgroup analysis according to LVEF, adjusted with clinical factors, GLS was significant predictive for outcome for the patients with mildly depressed (LVEF 40–50%, HR 2.25, p<0.001) and significantly depressed (LVEF<40%, HR 1.28, p = 0.016) systolic function, although GCS and LVEF lost their power with LVEF<40%. For the patients with preserved LVEF (>50%), GLS, GCS and LVEF did not show significant predictive power.

Conclusions

GLS is a most powerful predictor of outcome in successfully reperfused STEMI patients, especially with depressed LV dysfunction, although GCS and LVEF lost their predictive power for the patients with significantly depressed LV function. However, GLS did not predict outcome for the patients with preserved LVEF (>50%).

Clinical modifiers for heart failure following myocardial infarction

Heart failure (HF) is a clinical syndrome that occurs when the ability of the heart to meet the requirements of the body fails. Myocardial infarction (MI) is a common antecedent event that predisposes a patient to HF. Loss of cardiac function following MI occurs in the context of myocyte death and ventricular remodeling. The clinical significance of HF following MI is underscored by the fact that among MI survivors, the risk of death is markedly elevated in those who develop HF compared with those who do not. Various modifying factors associated with the development of HF following MI have been identified. Use of multimodality therapy with improved clinical outcomes for HF has increased the need to specifically identify the failing heart at an earlier stage. The ability to identify heart failure early in its pathogenesis will enable finer risk stratification following MI. This article reviews various risk predictors for the development of HF following MI.

Prognostic use of echocardiography 1 year after a myocardial infarction

BACKGROUND

Left ventricular (LV) and right ventricular (RV) function are known predictors of morbidity and mortality after an acute myocardial infarction (MI). However, the prognostic use of a late evaluation of cardiac function after an MI remains unclear.

METHODS

We analyzed echocardiograms obtained 1 year after MI in patients with LV dysfunction at baseline (ejection fraction [EF] < or = 40%) from 291 patients enrolled in the SAVE echocardiographic substudy who did not develop heart failure (HF) or a recurrent MI during this first year. Left ventricular EF and RV fractional area change were assessed.

RESULTS

After a median follow-up of 22 months after the 1-year echocardiogram, a low LVEF (< 30%) at 1 year was associated with an increased risk of death and/or HF (hazards ratio [HR] 2.7, 95% CI 1.3-5.3). Presence of RV dysfunction was also associated with an increased risk of death (HR 8.9, 95% CI 3.5-22.1), development of HF (HR 7.1, 95% CI 3.4-15.0), and the composite end point of death or HF (HR 7.6, 95% CI 4.1-14.2). In multivariate analyses, both low LVEF and RV dysfunction remained independently predictive of the composite end point of death or HF. Patients with biventricular dysfunction were at the greatest risk of death and/or HF (HR 19.4, 95% CI 8.2-46.0) in follow-up.

CONCLUSIONS

In a stable population of survivors of MI, impaired LV and RV function at 1 year after MI are independently and additively predictive of increased risk of HF or death.

Predictors of late development of heart failure in stable survivors of myocardial infarction: the CARE study

OBJECTIVES

We sought to determine the predictors of heart failure (HF) development in long-term survivors of myocardial infarction (MI).

BACKGROUND

Modern strategies of acute MI care have resulted in an increasing proportion of survivors at heightened risk of future non-fatal events, including HF.

METHODS

We assessed the risk of developing HF in 3860 stable MI patients without a previous history of HF, who were enrolled in the Cholesterol And Recurrent Events (CARE) trial a median of 10 months post MI. Baseline characteristics of patients who did or did not develop HF during the five years of observation were assessed.

RESULTS

A total of 243 patients (6.3%) developed HF in a linear pattern at a rate of 1.3%/year. Heart failure development markedly increased the risk of death (hazard ratio 10.2, 95% confidence interval 7.7 to 13.5). Fifty-seven patients (23.5%) who developed HF had a recurrent MI between enrollment and the onset of HF, increasing the risk fivefold. The most important predictors of HF were age and left ventricular ejection fraction. Other predictors included diabetes, history of hypertension, previous MI, and baseline heart rate. Moderate exercise three or more times per week was independently associated with a 30% lower risk of HF.

CONCLUSIONS

Heart failure post MI occurs in a time-dependent fashion, which is usually not a direct consequence of a detectable interim MI. Patients who experience late-onset HF have a 10-fold increased risk of death compared with other MI survivors. Baseline characteristics can risk stratify patients at high risk of subsequent HF.

Right ventricular dysfunction and risk of heart failure and mortality after myocardial infarction

OBJECTIVES

The aim of this study was to determine the prognostic value of right ventricular (RV) function in patients after a myocardial infarction (MI).

BACKGROUND

Right ventricular function has been shown to predict exercise capacity, autonomic imbalance and survival in patients with advanced heart failure (HF).

METHODS

Two-dimensional echocardiograms were obtained in 416 patients with left ventricular (LV) dysfunction (ejection fraction [LVEF] < or = 40%) from the Survival And Ventricular Enlargement (SAVE) echocardiographic substudy (mean 11.1 +/- 3.2 days post infarction). Right ventricular function from the apical four-chamber view, assessed as the percent change in the cavity area from end diastole to end systole (fractional area change [FAC]), was related to clinical outcome.

RESULTS

Right ventricular function correlated only weakly with the LVEF (r = 0.12, p = 0.013). On univariate analyses, the RV FAC was a predictor of mortality, cardiovascular mortality and HF (p < 0.0001 for all) but not recurrent MI. After adjusting for age, gender, diabetes mellitus, hypertension, previous MI, LVEF, infarct size, cigarette smoking and treatment assignment, RV function remained an independent predictor of total mortality, cardiovascular mortality and HF. Each 5% decrease in the RV FAC was associated with a 16% increased odds of cardiovascular mortality (95% confidence interval 4.3% to 29.2%; p = 0.006).

CONCLUSIONS

Right ventricular function is an independent predictor of death and the development of HF in patients with LV dysfunction after MI.

Relationship between serum amino-terminal propeptide of type III procollagen and changes of left ventricular function after acute myocardial infarction

BACKGROUND

The amino-terminal propeptide of type III procollagen (PIIINP) is a marker of type III collagen synthesis, which has previously been shown to correlate with infarct size in nonthrombolyzed myocardial infarction (MI) and to provide prognostic information after MI.

METHODS AND RESULTS

The relationship between PIIINP and changes of left ventricular (LV) function was studied in 47 consecutive patients with first acute MI and 16 control subjects. Serum PIIINP analysis was measured daily during hospitalization and on days 90, 180, and 360. LV function was assessed by echocardiography on days 1, 5, 90, and 360. Patients with MI were stratified according to their serum PIIINP value at day 4 (group A, </=5.0 microg/L; group B, >5.0 microg/L). On arrival, LV function and size were comparable between groups A (n=31) and B (n=16). LV ejection fraction, initially depressed (day 1: group A, 47+/-7% versus group B, 47+/-8%; P=NS), increased significantly in group A (day 360: 54+/-8%, P<0.001) but was unchanged in group B (day 360: 43+/-8%, P=NS). LV volumes increased significantly in group B (P<0. 05) but not in group A. Furthermore, patients in group B developed signs of restrictive LV diastolic filling. Multivariate regression analysis identified PIIINP >5.0 microg/L and deceleration </=140 ms as independent predictors of cardiac death or complicating heart failure during follow-up.

CONCLUSIONS

PIIINP assessed in the subacute phase of MI relates to long-term changes of LV function and provides clinical prognostic information.

[Clinical prediction of the early prognosis in acute myocardial infarct]

Several clinical factors can influence the pathophysiology, clinical course and prognosis of acute myocardial by different means. Some of them may be easily detected through the history, physical examination or ECG in an early phase. The knowledge of these factors may help the therapeutic decision making of patients with myocardial infarction. The influence for the main clinical factors (age, sex, risk factors, cardiologic antecedents and evolutive findings) on the short-term prognosis of acute myocardial infarction is reviewed. An analysis of the likely mechanisms of the influence of these factors on infarct prognosis is also performed.

Digital ventriculography: valid on-line calculation of cardiac volumes by corrected computer densitometry in coronary artery disease

Cardiac catheterization facilitates the assessment of left ventricular function in coronary artery disease (CAD). Digital left ventriculography offers the potential for an on-line quantitative determination of left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV). These are routinely evaluated by the area-length method (ALM), which is considered as a standard. Densitometry (DENS) is an alternative method but may lead to calculated underestimations. The purpose of this study was to investigate the accuracy of corrected DENS for LVEDV and LVESV in comparison with ALM in single-plane 30 degrees right anterior oblique (RAO) projection. The computer densitometric correction equation was adapted from the linear regression analysis (y = 0.86x + 2.73) in cardiac models and applied to the analysis of digital left ventriculograms in patients suffering from CAD. The study of cardiac models yielded highly significant correlations (r > or = 0.9; P < or = 0.001) between true volumes and both DENS and ALM. DENS and ALM correlated highly significantly (r > or = 0.9; P < or = 0.001) with a low standard error of estimate (SEE) of +/-9.5 mL. The comparison of DENS and ALM in 44 patients' digital ventriculograms exhibited highly significant (r = 0.74; P < or = 0.001) correlations for noncorrected and corrected LVEDV. Systematic underestimation by DENS of LVEDV disappeared after correction and SEE decreased from +/-23.7 to +/-19.2 mL. DENS and ALM correlated highly significantly for LVESV (r = 0.78; P < or = 0.001; SEE +/- 15.6 mL +/- 13.5 mL, respectively) after correction. Following correction, mean values for DENS increased from 116 +/- 32 to 132 +/- 37 mL (LVEDV) and 50 +/- 22 to 55 +/- 25 mL (LVESV). For ALM, mean values decreased from 159 +/- 35 to 127 +/- 28 mL (LVEDV) and 55 +/- 25 to 46 +/- 21 mL (LVESV). This study shows that LVEDV and LVESV can be reliably analyzed on-line by corrected computer densitometry. Method-related errors of both DENS and ALM are present and account for minor volume deviations.

On-line evaluation of systolic performance by densitometry in digital left ventriculography

The angiocardiographic evaluation of left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volumes and ejection fraction (EF) is routinely performed by the area-length method (ALM) but may lead to erroneous results. Digital imaging in real time allows densitometric procedures of determining left ventricular (LV) performance to be applied alternatively. In this study, we present densitometric algorithms for the analysis of LVEDV, LVESV, and EF from digital image data, establish accuracy and reproducibility, and determine value and limitations in comparison with ALM in single-plane 30 degrees right anterior oblique (RAO) projection. A linear relationship between iodine depth and measured densities is mainly burdened with scatter radiation and beam hardening which reduce primary radiation and suppress iodine depth. However, facilities such as deconvolution and correction algorithms are capable of reducing these sources of error. In the present study, computer-analyzed contrast images of iodine-filled wedges and spheres showed a near-linear relationship between iodine depth between 50-100 mg/cm2 and measured densities. Contrast images of heart casts and LV angio-grams of 54 patients were obtained with a digital image acquisition and processing system, and evaluated by two independent observers. The phantom study resulted in significantly (p < or = 0.01) better densitometric standard errors of estimate for volumes [3.3 ml densitometry (DENS) vs. 8.9 ml (ALM)] and simulated EF [4.3% (DENS) vs. 7.8% (ALM)] than ALM. The standard error of estimate for the comparison between both methods was 8.4 ml for volumes and 7.5% for EF. Densitometric volumes tended to underestimate volumes calculated by ALM. The angiographic study of patients demonstrated significant correlations between both methods (LVEDV r = 0.78, LVESV r = 0.83, total volumes: r = 0.89; EF r = 0.88). The standard errors of estimate can be ascribed to systematic, method-related errors of both DENS and ALM (LVEDV +/- 28.9 ml, LVESV +/- 23.4 ml, total volumes (EDV and ESV) +/- 27.1 ml; EF +/- 8.1%). The intra- and interobserver variability, respectively, exhibited significantly smaller (p < or = 0.01 and p < or = 0.05, respectively) standard errors of estimate for densitometric EF [4.6% (DENS) vs. 8.5% (ALM) and 7.1% (DENS) vs. 10.3% (ALM), respectively]. Inclined but not significant differences were found for LVEDV and LVESV. In conclusion, the data presented indicate that the calculation of LV volumes and EF in digital left ventriculography may be performed accurately by densitometric calculation in single-plane 30 degrees RAO projection. Minor underestimations in densitometric volume determination may be anticipated in the evaluation of LV geometry.

Prognostic significance of right ventricular dysfunction in patients with acute inferior myocardial infarction and right ventricular involvement

Little is known about the influence of right ventricular (RV) dysfunction on prognosis of patients with acute inferior myocardial infarction (IMI) and RV involvement. Therefore, 99 consecutive patients (mean age 56.6 +/- 3.4 years) with RV involvement during acute IMI were followed for a 12-month period to clarify the influence of acute RV dysfunction on short- and long-term survivals. Forty-one patients with IMI evolved with severe arterial hypotension due to RV dysfunction, while 58 patients had no hemodynamic impairment due to RV involvement. Basal hemodynamic data (mean +/- SD) for patients with RV dysfunction were blood pressure (BP) 92/59 +/- 22/20 mmHg, systemic vascular resistance (SVR) 2314 +/- 252 dynes.s.cm-5, and cardiac index (CI) 1.3 +/- 0.3 l/min/m2. Patients without RV dysfunction demonstrated BP 113/74 +/- 20/16 mmHg (p < or = 0.05), SVR 1324 +/- 354 dynes.s.cm-5 (p < or = 0.01), and CI 2.6 +/- 0.5 l/min/m2 (p < or = 0.05). Angiographic differences noted were that hemodynamically compromised patients showed lower RV ejection fractions (0.27 +/- 0.08) than patients without hemodynamic disturbance [0.41 +/- 0.11 (p < or = 0.05)]; however, left ventricular ejection fractions were 0.48 +/- 0.10 and 0.52 +/- 0.12, respectively. Short- and long-term mortality rates were assessed during the follow-up period. Patients with hemodynamic impairment due to RV infarction had a higher mortality rate for the first month and for 11 subsequent months post MI than patients without hemodynamic impairment, that is 24.4 vs. 6.9 and 14.6 (p <or = 0.05) vs. 3.4 (p < or = 0.05), respect ively.(ABSTRACT TRUNCATED AT 250 WORDS)

The prognostic value of right atrial pacing after acute myocardial infarction

We performed right atrial pacing in 90 consecutive patients 10 to 30 days (mean 16.8 days) after acute myocardial infarction. Right atrial pacing was normal in 28 patients, depression of the ST segment occurred in 27 patients, systolic blood pressure fell below control values in 20 patients and, in 15 patients, right atrial pacing was non-diagnostic. Follow-up was from 12 to 28 months (mean = 17.3). Global mortality was 11.1%, with none of the patients with normal tests dying, 11% of those with ST depression, 30% of those with induced hypotension (P less than 0.01) and 7.1% of those in whom pacing was non-diagnostic. Patients with high clinical risk at discharge in Peel Class III-IV, showed 41.2% mortality during the period of follow-up. None of those had shown normal responses to pacing, but those dying included 50% of the patients with ST depression and 66.7% of those in whom right atrial pacing induced hypotension. Development of new angina during the period of follow-up was more frequent among the patients with ST depression (33.3%) (P less than 0.001). Thus, our results showed that right atrial pacing was useful in predicting mortality after acute myocardial infarction. In patients at high risk, we observed that a fall of systolic blood pressure was the best predictor of mortality.

Estimation of the risk of death during the first year after acute myocardial infarction from systolic time intervals during the first week

Patients who survived for the first seven days after acute myocardial infarction were followed up for a further 51 weeks. During these 51 weeks there were 123 deaths and 477 eventual survivors. Approximately half of the deaths occurred during the first 3 weeks of follow up. The deaths were predicted with 75% sensitivity and 73% specificity by a discriminant analysis based upon six variables seen during the first 7 days; predictions of death and survival were 55% and 92% accurate respectively. These six variables were, in ascending order of prognostic importance, the occurrence of bundle branch blocks, the administration of a diuretic, the age of the patient, the presence of diabetes mellitus, a previous myocardial infarction, and the ratio of the measured left ventricular pre-ejection and ejection periods. Many other monitored variables, although univariately associated with death, contributed nothing further to the multivariate assessment of mortality risk.

Increased myocardial contractility during intravenous insulin infusion in type 1 (insulin-dependent) diabetic patients: an echocardiographic study

On two occasions eight insulin-dependent diabetic patients were connected to an artificial beta-cell, and insulin was administered by continuous intravenous infusion at a rate of 2 mU/kg/min, producing a moderate hyperinsulinaemia (mean 116 microU/ml). At random, blood glucose was kept constant by concomitant glucose infusion, or allowed to decrease to a mean value of 5.3 mmol/l. M-mode echocardiography was performed before, at 90 and at 180 min of insulin infusion. Following the euglycaemic insulin infusion periods, the fractional shortening of the left ventricle increased from 38.2% to 41.0 and 40.2%, respectively (p less than 0.02). The diastolic diameter (pre-load) and end-systolic meridional wall stress (after-load) remained constant in this experiment. In contrast, no change in fractional shortening could be demonstrated during falling blood glucose, possibly because pre-load was altered to a significant degree during this experimental condition. In conclusion, concomitant infusion of insulin and glucose, producing an euglycaemic hyperinsulinaemia, is followed by increased myocardial contractility.

Contrast echo washout curves from the left ventricle: application of basic principles of indicator-dilution theory and calculation of ejection fraction

Time-intensity curves can be obtained from contrast echocardiography of the left ventricle. The purposes of this study were: 1) to verify whether these curves conform to the basic principles of indicator-dilution theory; and 2) to derive indexes of left ventricular ejection fraction from curve analysis. In seven closed chest dogs, 31 doses of the polysaccharide agent SHU-454 were injected into the left ventricular cavity during apical four chamber two-dimensional echocardiography. Data were obtained at different levels of ejection fraction, which were induced by changes in preload, afterload and contractility, and measured by single plane Simpson's rule analysis of digital subtraction left ventriculograms. In a subset of two dogs, eight incremental doses (from 1 to 8 ml) of SHU were injected in the basal state. Contrast echocardiograms were digitized off-line, the mean gray level/pixel of a region of interest inside the left ventricular cavity was measured, and the average value for three systolic frames of each beat was used to obtain time-intensity curves. A good correlation was observed between the peak of the time-intensity curve and the quantity of contrast injected (correlation coefficient r = 0.91 by a logarithmic fit). The echo intensities observed in each animal were subsequently transformed in quantity of contrast according to these functions and their natural logarithm was calculated both with and without background subtraction. All curves relating time and the natural logarithm of the corrected intensity exhibited a descending rectilinear portion (washout) in which the correlation was very good (r = 0.97 +/- 0.02 = mean +/- SD) and which was not significantly affected by background subtraction. The validity of this fit was also unaffected by heart rate (55 to 158 beats/min) and angiographic ejection fraction (22 to 74%), and only minimally influenced by duration of contrast washout (3.3 to 14.6 seconds). Ejection fraction was calculated by an algorithm derived from indicator-dilution theory: ejection fraction = [1 - e(-bd)] X 100, where b = slope of the curve and d = cardiac cycle duration. Linear regression analysis between values of ejection fraction derived by angiography and contrast echo yielded r = 0.73. A second index, based on b and d, was derived by multiple regression analysis. Linear regression analysis of this index and angiographic ejection fraction yielded a correlation of r = 0.87.(ABSTRACT TRUNCATED AT 400 WORDS)

Determination of left ventricular ejection fraction by computer densitometric analysis of digital subtraction angiography: experimental validation and correlation with area-length methods

Conventional methods for calculating left ventricular (LV) ejection fraction (EF) require accurate edge definition and geometric assumptions, which may be compromised in the presence of dyssynergy. Computer densitometric analysis (CDA) of digital subtraction angiography offers the potential for calculation of EF, independent of LV shape, by comparing summated brightness for regions of interest at end diastole and end systole. Therefore, the accuracy of CDA was validated for 2 mechanical heart models of differing geometry, spherical and rectangular. Both models confirmed the close correlation between calculated and measured EF (r = 0.98 and r = 0.99, respectively). Subsequently, the CDA was compared with single and biplane area-length EF calculations in 72 patients, half with a previous myocardial infarction. In patients without previous myocardial infarction, CDA correlated closely with both single-plane and biplane EF (r = 0.91 and 0.93, respectively). The close correlation was maintained regardless of whether CDA was applied to direct LV injection or intravenous digital subtraction angiography. However, in 36 patients with previous myocardial infarction, CDA correlated less closely with single-plane (r = 0.74) than with biplane (r = 0.86) area-length EF. Thus, CDA permits calculation of EF without geometric assumptions, and may be superior to the area-length method in patients with LV dyssynergy after myocardial infarction.

Are right and left ventricular ejection fractions equal? Ejection fractions in normal subjects and in patients with first acute myocardial infarction

Right and left ventricular ejection fractions (RVEF and LVEF) were determined by radionuclide imaging in 37 normal subjects and 37 patients by means of (1) the traditional way of calculating ejection fraction from first-pass time-activity curves of each ventricle generated from a single fixed ventricular region of interest, (2) dual first-pass time-activity curves generated from the end-diastolic and end-systolic regions, respectively, and (3) the multigated equilibrium method, also applying separate regions in end-diastole and end-systole for each ventricle. Values for RVEF measured by method 2 were significantly higher than values obtained by methods 1 and 3. In normal subjects, the values for RVEF measured by method 2 were equal to the values for LVEF determined by either this method or the equilibrium technique. Methods 1 and 3 had a tendency for underestimation of RVEF, probably because of inclusion of right atrial activity into the right ventricular region of interest. Methods 2 and 3 were applied to measure RVEF and LVEF, respectively, in 153 patients in the second week after first acute myocardial infarction. Among these, 25% had normal ejection fractions, 47% had a decrease in only LVEF, 8% a decrease in only RVEF, and 20% a decrease in both RVEF and LVEF.

Value of radionuclide angiography for predicting specific cardiac events after acute myocardial infarction

The value of rest and exercise radionuclide angiography (RNA) for predicting specific events including death, recurrent acute myocardial infarction (AMI), coronary care unit readmission for unstable chest pain, and medically refractory angina after AMI was studied in 106 consecutive survivors of AMI. Analysis of the RNA variables using the Cox proportional hazards regression model yielded significant associations of the time to death with ejection fraction at rest and during exercise (X2 = 11.1 and 14.0, respectively). Both variables added significant prognostic information to the clinical assessment (X2 = 4.3 and 5.7, respectively). The change in ejection fraction from rest to exercise predicted the time to coronary artery bypass grafting for medically refractory angina before (X2 = 21.0) and after (X2 = 13.2) adjustment for the clinical descriptors, but did not predict death or other non-fatal events. Significant correlations were found between RNA variables and a variety of clinical descriptors previously reported to have prognostic significance. Clinical and RNA variables that are measures of left ventricular function were predictive of subsequent mortality, whereas those that reflect residual potentially ischemic myocardium were predictive of subsequent nonfatal ischemic events. Rest and exercise RNA after AMI provides significant prognostic information regarding specific events during follow-up independent of that provided by clinical assessment.

Usefulness of the chest x-ray for predicting abnormal left ventricular function after acute myocardial infarction

We evaluated 229 patients discharged after a definite acute myocardial infarction. Pulmonary venous congestion determined from chest x-ray films during the hospitalization and at discharge and the cardiothoracic ratio at discharge were compared to the left ventricular ejection fraction measured at discharge by a gated radionuclide technique. During hospitalization, pulmonary venous congestion was found on at least one x-ray frame in 94 patients (41%). At discharge 134 patients (59%) had abnormal ejection fraction (less than 0.51) and 35 had pulmonary venous congestion (15%). The sensitivity of the x-ray for detecting an abnormal ejection fraction was 20% when pulmonary venous congestion was observed on the discharge x-ray film (specificity 92% and predictive value 77%), 52% if pulmonary venous congestion was present on any x-ray film during the hospitalization (specificity 74% and predictive value 73%), and 47% if the cardiothoracic ratio was abnormal (greater than or equal to 0.50) on the discharge x-ray film (specificity and predictive value 66%). We conclude that an abnormal x-ray film at discharge or during the hospitalization will identify approximately one-half of the abnormal ejection fractions at the time of hospital discharge. Therefore, to reliably assess left ventricular function, either for prognostic or therapeutic purposes in the individual patient, a more direct measure of left ventricular function such as radionuclide angiography must be obtained.

Prognosis of patients with diabetes mellitus after acute myocardial infarction

Sixty patients with diabetes mellitus who survived the coronary care unit phase of acute myocardial infarction (AMI) were followed an average of 19 months and the prognosis of diabetic patients was compared with that of 719 nondiabetic patients. The mortality rate was 25% in diabetic patients and 8% in nondiabetic patients. These patients had been entered in a Multicenter Postinfarction Program, where analysis of the total data base showed 4 significant prognostic factors: cardiac symptoms before AMI, pulmonary rales when the patient was in the coronary care unit, more than 10 ventricular premature complexes per hour recorded on Holter monitor just before discharge, and a radionuclide ejection fraction of less than 40%. Of these 4 factors, only cardiac symptoms before AMI was significantly more common in diabetic patients (57% in diabetic vs 36% in nondiabetic patients). When each of these 4 factors was stratified for severity, the mortality rate was always higher in diabetic patients. The data were examined to determine other factors in diabetic patients who died. Pulmonary rales was significantly more common in diabetic patients who died (6% in survivors vs 42% in patients who died). In a multivariate analysis of both diabetic and nondiabetic patients, 5 factors were significant determinants of prognosis. They are, in order of entry into the model, rales (p less than 0.001), ejection fraction less than 40% (p less than 0.001), diabetes (p less than 0.001), symptoms before AMI (p = 0.009), and more than 10 ventricular premature complexes per hour (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Natural history of severe left ventricular dysfunction after myocardial infarction

The prevalence and prognosis of severe left ventricular dysfunction after infarction was prospectively analyzed in a series of 259 male patients aged 60 years or less surviving an acute myocardial infarction. All patients underwent coronary angiography 30 days after the acute event and were followed up for a mean period of 34 months (range, 15 to 55 months). Forty-five patients (17 percent) were found to have severe left ventricular dysfunction (ejection fraction less than or equal to 30 percent). Comparison of patients with and without severe impairment of left ventricular function showed the former to have a lower cardiac index (p less than 0.001), higher left ventricular end-diastolic volume index (p less than 0.001), and a higher prevalence of three-vessel disease (p less than 0.025) and of total or subtotal occlusion of at least one coronary artery (p less than 0.025). While the occurrence of congestive heart failure was higher in patients with severe left ventricular dysfunction (p less than 0.001), the probability of developing angina was similar in both groups. Cox's regression analysis showed ejection fraction to be the only independent predictor of survival in patients with severe impairment of left ventricular function. An ejection fraction of 20 percent or less identified a subset of patients with the highest mortality (62 percent at four years), significantly different from that of patients whose ejection fraction was between 21 and 30 percent (28 percent) (p less than 0.001).

Effects of resting ischemia assessed by thallium scintigraphy on QRS scoring system for estimating left ventricular function quantified by radionuclide angiography in acute myocardial infarction patients

The purpose of this study was to determine whether resting ischemia limits the usefulness of the QRS scoring system in predicting left ventricular (LV) ejection fraction (EF) in patients with acute infarction. We studied 48 patients after acute infarction by means of 12-lead ECG, thallium-201 scintigraphy, and radionuclide angiography. The thallium-201 scintigrams showed fixed defects in 25 patients, perfusion defects with partial or complete redistribution in the delayed images in 19 patients, and normal images in the remaining four patients. In the 48 patients there was a significant correlation between the QRS score and LVEF (r = -0.67; p less than 0.001). Patients with fixed defects showed a better correlation than patients with resting ischemia (r = -0.77 vs r = -0.60). A QRS score of 3 or less was used to separate patients with LVEF of 40% or greater from those with lower LVEF in patients with fixed defects (p = 0.0005), but this cutoff did not categorize patients with resting ischemia as to LVEF. Thus the presence of rest ischemia in patients with acute infarction may affect the correlation between QRS score and LVEF.

Comparison of two-dimensional echocardiography with gated radionuclide ventriculography in the evaluation of global and regional left ventricular function in acute myocardial infarction

Two-dimensional echocardiography and gated radionuclide ventriculography were performed in 93 patients (66 men, 27 women; mean age 61 years) with 95 episodes of acute myocardial infarction within 48 hours and at 10 days after infarction. Electrocardiographic sites of infarction were: 35 anterior, 49 inferoposterior and 11 nonlocalized. Abnormal motion of the anterior wall, septum or apex was seen in 97 and 100% of anterior infarctions by radionuclide ventriculography and echocardiography, respectively. Abnormal motion of an inferior or posterior wall segment was seen in 91% of inferoposterior infarctions by echocardiography versus 61% seen by radionuclide ventriculography. Ejection fractions determined by echocardiography and radionuclide ventriculography correlated well (r = 0.82) and did not change from the first 48 hours to 10 days after infarction (0.48 +/- 0.14). Similarly, wall motion score showed minimal change from the first 48 hours to 10 days. In-hospital mortality was 37 and 42% in patients with an ejection fraction of 0.35 or less by echocardiography and radionuclide ventriculography, respectively. No mortality was seen in patients with an ejection fraction above 0.40 by either test. The echocardiographic wall motion score was also predictive of mortality (40 versus 2%; score less than or equal to 0.50 versus greater than 0.50). The 1 year mortality rate in the 81 short-term survivors was 17%. Mortality was lowest in patients with an ejection fraction above 0.49 or wall motion score above (0.79 (2 to 5%) and worse in those with an ejection fraction below 0.36 or wall motion score below 0.51 (36 to 63%) by either technique. Thus in acute myocardial infarction, echocardiography and radionuclide ventriculography provide a comparable assessment of left ventricular function and wall motion in anterior infarction. Echocardiography appears more sensitive in detecting inferoposterior wall motion abnormalities. Both techniques are capable of identifying subgroups of patients with a high risk of death during the acute event and with an equally high mortality rate over a 1 year follow-up period.

Clinical value of phase and amplitude images and left ventricle time-activity curves in assessing patients with acute myocardial infarction

The purpose of this study was to assess the clinical usefulness of phase and amplitude images and of the left ventricle time-activity curve (LVTAC) obtained by equilibrium gated radionuclide ventriculography (EGRV) in patients with acute myocardial infarction (AMI). Fifty-six patients were studied within 4 days of the onset of AMI by EGRV; of these 49 also underwent first-pass (FP) angiocardiography, for comparison with EGRV, and 21 underwent repeated EGRV 3 months after AMI. Phase and amplitude images were obtained by Fourier analysis. LVTAC analysis was performed by a third degree polynomial fitting to determine peak ejection rate (PER) and peak filling rate (PFR). A substantial equivalence of EGRV and FP methods was demonstrated, as regards left ventricle ejection fraction (LVEF), while a sharp superiority of EGRV with Fourier analysis was shown with regard to the sensitivity of RWM abnormality detection. With only one exception all the cases showed RWM abnormalities, while LVEF was normal in 21 of 27 patients with less than three affected segments. The most sensitive global function index was the LVPFR. In the acute phase regional dyskinesis was observed in 14 of 56 patients. About 40% of our cases showed an improvement of the kinetic abnormalities 3 months after AMI. The highest rate of improvement was observed in the group with ECG patterns of limited infarction and with normal LVEF.

Prediction of late mortality after myocardial infarction from variables measured at different times during hospitalization

The long-term prognostic importance of sets of variables from different times in the hospital course after acute myocardial infarction was examined in 818 patients discharged from the hospital. Cardiac mortality during the first year after discharge was 11.1%. For the end point death within 1 year after admission, discriminant function analysis identified 5 important factors from the history and the first 24 hours of hospitalization: maximal level of blood urea nitrogen, previous myocardial infarction, age, displaced left ventricular apex (abnormal apex) on physical examination, and sinus bradycardia (negative correlation). When data from the entire hospitalization were included, extension of infarction and maximal heart rate were also selected. When variables obtained at discharge were included, only the presence of S3 gallop and abnormal apex were selected. In subgroups of patients, neither the left ventricular ejection fraction nor the presence of complex ventricular arrhythmias during a 24-hour ambulatory monitoring were independent predictors. Correct prediction was similar for each analysis, with 55 to 60% of the deaths and 79 to 81% of survivors correctly identified. The high-risk group consisted of 25% of the patients with 28 to 30% predictive value for death in the first year. In conclusion, outcome up to 1 year after acute myocardial infarction can be predicted early after admission. Addition of more information later during the hospitalization and at discharge did not improve correct prediction and may be redundant for prognostic evaluation.

Evaluation of left ventricular contractile pattern by intravenous digital subtraction ventriculography: comparison with cineangiography and assessment of interobserver variability

The accuracy and reproducibility of measurements of left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) and regional wall motion obtained by digital subtraction ventriculography (DSV) were compared with values of direct cineangiography in 40 patients, 21 of whom were ambulatory. DSV was performed with a 1-second, 30-ml contrast injection, which yielded real-time fluoroimages composed of 512 X 512 pixels at 30 frames/s. Single-plane right anterior oblique LV volumes were calculated by area-length methods for both DSV and cineangiography. Wall motion was assessed as percent area shortening for 12 equal myocardial segments, with results classified as abnormal if greater than 2 standard deviations below the mean of 20 normal values. DSV exhibited close correlation with angiography for EDV (r = 0.88), ESV (r = 0.92) and EF (r = 0.93). Intravenous DSV and direct cineangiography were concordant in classification of LV contractile pattern in 436 of 480 (91%) myocardial segments. Measurements of DSV obtained by 2 observers showed close correlations for EDV (r = 0.88), ESV (r = 0.95) and EF (r = 0.94), and wall motion classification was in agreement in 434 of 480 (90%) LV segments. Artifacts induced by respiratory motion, persistence of contrast in the right ventricle or left atrium, or low cardiac output may have contributed to the discrepancies observed. These data indicate that DSV is accurate in assessing LV volume and EF, correlates well with cineangiography and exhibits good interobserver reproducibility.

Early recognition of the patient at late high risk: incomplete infarction and vulnerable myocardium

The process of identifying patients with myocardial infarction (MI) at high risk after hospital discharge should begin at admission. By using basic clinical and laboratory information, enhanced by a wide variety of noninvasive tests, not only can individual patients at risk be recognized, but also the processes that determine risk can, at least in part, be appreciated. Outcome is affected by the extent of damaged tissue and, apparently, by the amount of potentially ischemic muscle. MI may change the coronary circulation such that a new and fragile balance between supply and demand results, both within and outside the infarct zone; that is, the infarct may be incomplete and the viable muscle within it may then be vulnerable to later ischemia. Muscle outside the infarct zone may be left in much the same precarious state. Also, coronary spasm may not be infrequent in the weeks after MI. These factors together may underlie recurrent post-MI myocardial ischemia.

Prognostic value of submaximal exercise radionuclide ventriculography after myocardial infarction

Submaximal exercise testing with radionuclide ventriculography (RVG) was performed in 117 patients before hospital discharge 17 +/- 7 days (+/- standard deviation) after an acute myocardial infarction (MI). The hypothesis tested in these studies was that submaximal exercise testing coupled to RVG allows the identification of patients at risk for future ischemic events in the subsequent 6 months, irrespective of MI location and type. The sites of MI were characterized as anterior transmural in 33, inferior transmural in 39, limited nontransmural in 18, extensive nontransmural in 24 and indeterminant in 3. During 6 months of follow-up, 9 patients died, 14 had recurrent MI, 18 had refractory angina pectoris, 16 had limiting angina and 17 had congestive heart failure. Discriminant function analysis ranked exercise changes in left ventricular (LV) ejection fraction and end-systolic volume the most important of all clinical, exercise and scintigraphic variables for predicting future cardiac events. The predictive accuracy of changes in LV ejection fraction and end-systolic volume were 93 and 91%, respectively, for the entire group, and were significantly more sensitive than any degree of ST-segment depression or elevation (p less than 0.001). These findings were generally independent of MI location and type. Thus, submaximal exercise RVG after MI is an accurate means of identifying patients at risk for major cardiac events in the 6 months after hospital discharge.

Prognostic value of resting and submaximal exercise radionuclide ventriculography after acute myocardial infarction in high-risk patients with single and multivessel disease

In patients who survive the acute phase of myocardial infarction, those with multivessel coronary artery disease generally have a worse prognosis than those with single-vessel disease. However, some patients with significant multivessel stenoses have a good prognosis, whereas some with a significant single-vessel stenosis have a poor prognosis. Thus, although definition of coronary anatomy may be helpful, it is a not a fail-safe prognosticator. In this retrospective analysis, the association of abnormalities at rest and during submaximal exercise testing with radionuclide ventriculography after acute myocardial infarction with major cardiac complications (death, recurrent infarction, severe angina or congestive heart failure) in the ensuing 6 months was assessed in patients with single and multivessel disease. Coronary angiography and submaximal exercise testing with radionuclide ventriculography were performed within 3 months of each other in 42 patients. Eleven of the 16 patients with single-vessel coronary stenosis had major cardiac complications. The subsequent course of these 16 patients was correctly predicted by left ventricular ejection fraction (LVEF) less than or equal to 0.40 in 8 patients, by LVEF less than 0.55 in 7 patients, by failure of LVEF to increase by 0.05 units in 13 patients, and by an increase in left ventricular end-systolic volume index (LVESVI) during exercise greater than 5% above baseline in 11 patients. Of the 26 patients with multivessel coronary artery disease, 24 had major cardiac complications. The subsequent course of these 26 patients was correctly predicted in 13 by LVEF less than or equal to 0.40, in 20 by LVEF less than 0.55, in 25 by a failure of LVEF to increase by 0.05 units during exercise, and in 20 by an increase in LVESVI by greater than 5% during exercise. Thus, submaximal exercise testing with radionuclide ventriculography may provide valuable prognostic information concerning the occurrence of major cardiac events after myocardial infarction not only in patients with multivessel disease, but also in those with single-vessel disease. Exercise-induced abnormalities of left ventricular function may have greater prognostic importance than the delineation of coronary arterial anatomy or the assessment of residual left ventricular function at rest.

Comparison of early thallium-201 scintigraphy and gated blood pool imaging for predicting mortality in patients with acute myocardial infarction

The extent of abnormality in early thallium-201 and gated cardiac blood pool scintigrams has been reported to be useful for predicting mortality in patients with acute myocardial infarction (AMI). To compare the two techniques, 91 patients admitted consecutively with evident or strongly suspected AMI underwent both imaging studies within 15 hours of the onset of symptoms. Patients with pulmonary edema or shock were excluded. AMI developed in 84% of patients, and 6-month mortality for the entire group was 16%. A thallium defect score of 7.0 or greater (corresponding to at least a moderate reduction of activity involving 40% of the left ventricular circumference) identified a subgroup of 14 patients with 64% 6-month mortality rate. Similarly, a left ventricular ejection fraction of 35% or less identified a high-risk subgroup of 10 patients with a 6-month mortality of 60%. Mortality in the remaining patients was 8% for thallium score less than 7 and 11% for ejection fraction greater than 35%. The mortality rate was highest among patients who had concordant high-risk scintigrams (five of six, 83%), lowest in those with concordant low-risk studies (five of 64, 8%) and intermediate in those with discordant results (four of 11, 36%). Of a number of clinical variables, only the appearance of Q waves, peak creatine kinase greater than 1000 IU/I, and history of infarction were significantly associated with mortality. High-risk thallium or blood pool scintigraphic results were significantly more predictive and a thallium score of 7 or greater was more sensitive for detecting nonsurvivors than ejection fraction 35% or less at a similar level of specificity. Stepwise multiple logistic analysis showed that the thallium score was the best predictor of mortality, but that appearance of Q waves and ejection fraction were additive. Using these three variables, 11 patients were calculated to have a 50% or greater chance of dying and eight (73%) actually died, compared with six of 70 (9%) with a calculated chance of death of less than 50%. These results in a prospectively identified and consecutive group of patients support the value of early thallium and blood pool scintigraphy for separating high- and low-risk subgroups of hemodynamically stable infarct patients.

Limitations of electrocardiographic scoring systems for estimation of left ventricular function

Four electrocardiographic scoring systems for the assessment of left ventricular function or presence of myocardial infarction were evaluated in 231 patients with coronary artery disease. Electrocardiographic scores were compared with radionuclide ejection fraction and thallium perfusion studies. The correlation between Wagner's modified QRS score and ejection fraction was only fair (r = -0.60). Askenazi's sum of R wave voltage score correlated poorly with ejection fraction (r = 0.44), as did Gottwik's sum of voltage score from the Frank lead electrocardiogram (r = 0.44). Rautaharju's Cardiac Infarction Injury Score did not reliably predict presence of infarction in the patient group, nor did it correlate well with ejection fraction (r = -0.49). None of the correlations were significantly improved when only patients with a history of a myocardial infarction, a thallium defect compatible with a scar or a diagnostic Q wave were considered. Although Wagner's QRS score correlated best with ejection fraction, all scoring systems had limited clinical usefulness for estimating ejection fraction.

Left ventricular functional alterations at rest and during submaximal exercise in patients with recent myocardial infarction

Submaximal exercise testing with radionuclide ventriculography was performed in 117 patients prior to hospital discharge 16.7 +/- 6.7 days (SD) following acute myocardial infarction. The hypothesis tested in this study was that patients with different locations and types of infarction have different functional responses to submaximal exercise prior to discharge. The distribution of the myocardial infarctions were anterior transmural in 33, inferior transmural in 39, anterior nontransmural in 23, inferior nontransmural in 19, and indeterminant in three. Patients with transmural infarction generally had significantly larger resting left ventricular volumes at end-diastole and end-systole and lower ejection fractions and systolic blood pressure/end-systolic volume indexes than patients with nontransmural infarctions (p less than 0.05). During submaximal exercise, the change in end-systolic volume was significantly different in these two groups. When patients were separated further into anterior and inferior transmural subgroups, the patients with anterior transmural infarction had significantly lower left ventricular ejection fractions and higher right ventricular ejection fractions than the group with inferior transmural infarction (p less than 0.05). In response to exercise, the group with anterior transmural infarction had a significant decrease in left ventricular ejection fraction and a blunted systolic blood pressure/left ventricular end-systolic volume index, in comparison to patients with inferior myocardial infarction (p less than 0.05); this was the only group to have a significant increase in end-systolic volume. The group variance for the parameters studied was large, particularly during exercise when the individual responses were frequently directionally opposite from the group means. The group with anterior transmural infarction was the most homogeneous, with 26 of 33 having a directionally abnormal response to submaximal exercise. It was concluded that the group with anterior transmural infarction generally displayed the most abnormal left ventricular function. However, despite significant group differences in resting ventricular function with different infarcts, the intragroup variability at rest and in response to exercise was too great to permit an accurate prediction of the subject's resting ventricular performance or to permit a prediction of exercise response based solely on location of the infarct.

The high risk patient after recovery from myocardial infarction: recognition and management

Patients at high risk for recurrent myocardial infarction or death can be identified after recovery from an acute myocardial infarction. Predictors of high risk at the time of initial hospital discharge may vary in different localities depending on the underlying baseline characteristics of the patient cohort. The medical records were analyzed of 139 patients discharged from San Francisco General Hospital after recovery from an acute myocardial infarction between July 1978 and September 1981. Multivariate stepwise discriminant analysis of 20 variables contributing to sudden and total death identified complex ventricular ectopic rhythm as the most important variable, followed by age. Failure to receive chronic long-acting nitrates was an independent variable contributing to total mortality but not to sudden death, while the presence of an initial anterior myocardial infarction and impaired left ventricular function were independent variables contributing to sudden death but not to total mortality. Routine 24 hour ambulatory monitoring, radionuclide ventriculography and submaximal stress tests performed during the second week after recovery from an acute myocardial infarction provide identification of a high risk cohort for subsequent recurrent myocardial infarction or death and permit appropriate interventions designed to lessen risk to be undertaken.

The interval ejection fraction: a cineangiographic and radionuclide study

To evaluate the clinical usefulness of the first-third ejection fraction (1/3 EF) for detecting patients with coronary artery disease (CAD), resting contrast ventriculography and first-pass radionuclide angiography with a high-count-rate, multicrystal camera system were performed in 47 subjects: 22 normal controls (group 1) and 25 patients with clinically stable angina pectoris and severe CAD (mean 2.3 vessels) without (group 2, n = 12) and with (group 3, n = 13) resting wall motion abnormalities. By contrast angiography, only group 3 had depressed global EF or 1/3 EF compared with control (global EF: group 1,0.71 +/- 0.09; group 2, 0.67 +/- 0.09 [NS]; group 3,049 +/- 0.05 [p less than 0.01 vs groups 1 and 2]; 1/3 EF: group 1,0.29% +/- 0.06;' group 2, 0.28 +/- 0.05 [NS]; group 3,0.22 +/- 0.05 [p less than 0.02 vs groups 1 and 2]). Whereas 11 of 25 CAD patients had global EF outside the normal range, only two of 25 had depressed 1/3 EF. Both had left ventricular asynergy and a depressed global EF. Studies performed using first-pass radionuclide angiography revealed similar results i.e., only four of 25 CAD patients, all with left ventricular asynergy and depressed global EF, had depressed 1/3 EF values. A wide range of 1/3 EF values was found in normal subjects by both techniques. Thus, the ejection fraction during the first third of systole at rest is of limited value for detecting patients with CAD.

Exercise testing early after myocardial infarction. Risks and benefits

Submaximal exercise testing in the early weeks following myocardial infarction appears to be safe in selected patient groups. Potential benefits of such testing includes: (1) promotion of patient self-confidence, (2) determination of post-hospital exercise prescription, (3) detection of arrhythmias, and (4) determination of post-hospital prognosis. However, the practical value of the apparent psychologic benefits and of the exercise prescription information in a patient not participating in formal exercise rehabilitation therapy is unclear. Detection of potentially important arrhythmias appears to be more adequately effected with 24-hour ambulatory electrocardiography, and detection of such arrhythmias appears to add relatively little prognostic information to that available from exercise electrocardiographic S-T analysis, or from resting radionuclide ejection fraction. Nonetheless, exercise-induced S-T segment depression can provide potentially useful prognostic information regarding morbid or fatal events during the year after infarction. Moreover, recent data suggest that exercise-induced angina and/or S-T segment depression can aid importantly in the noninvasive determination of the anatomic extent of coronary artery disease. The additional benefit or radionuclide cineangiographic determination of left ventricular function during exercise and of thallium 201 scintigraphic determination of myocardial perfusion during stress remain to be defined, although both approaches appear to provide important prognostic information. However, despite the potential benefits of exercise testing, in the absence of clinical trials of available therapy in the "high risk" patient defined by exercise testing, there remains an ill-defined relationship between the information available from exercise testing and the results of management decisions based on this information.

Assessment of cardiac risk 10 days after uncomplicated myocardial infarction

A total of 188 patients with uncomplicated acute myocardial infarction (long-term Norris prognostic index 3.2) were rapidly mobilised, underwent a symptom-limited exercise test around the day of discharge from hospital (day 10), and returned to work at a median of six weeks after the acute event. The incidence of cardiac death six months, one year, and three years after infarction was 2.7%, 4.5%, and 7.3% respectively, and the corresponding figures for recurrent heart attacks were 3.4%, 8.2%, and 18.5% respectively. The risk of recurrence of heart attack was predicted by three variables assessed at discharge--namely, a history of classical effort angina (p less than 0.01), radiological heart failure (p less than 0.05), and angina induced by the exercise test (p less than 0.05). The presence of any of these risk factors defined a group of patients with a sevenfold risk of recurrent heart attacks within six months of the initial acute infarct. It is concluded that these risk factors identify a group of patients with a high risk of recurrence early after infarction, in whom vigorous secondary prophylaxis is desirable.

The prognostic value of submaximal exercise testing with radionuclide ventriculography before hospital discharge in patients with recent myocardial infarction

To test the hypothesis that patients at risk of future cardiac events can be identified by sub-maximal exercise testing with radionuclide ventriculography (RVG), 61 patients were studied a mean of 19 +/- 1.0 days (+/- SEM) after acute myocardial infarction (MI). RVGs were used to measure left ventricular ejection fraction (LVEF), wall motion score (WMS), end-diastolic volume (EDV) and end-systolic volume (ESV), and the ratio of systolic blood pressure to ESV (P/V index) at rest and during submaximal exercise. Frank lead ECGs were analyzed for ST-segment change and arrhythmias. These patients were followed for a mean of 9.6 months (60 for 6 months or more and one for 3 months) to determine the incidence of cardiac death, recurrent MI, unstable or medically refractory angina, persistent congestive heart failure (CHF) or limiting angina; these problems were considered to be important cardiac events. At the 6-month follow-up, 37 patients had important complications: four patients died, five had MI, seven had unstable or medically refractory angina, 11 had persistent CHF and 10 had severe limiting angina. The sensitivity and specificity of RVG in predicting the important postinfarct complications listed above were 95% and 96% for failure to increase LVEF by at least 5 units, 95% and 96% for an increase in ESV of more than 5%, 97% and 88% for failure of the P/V index to increase by more than 35%, and 81% and 88%, respectively, for a decrease in WMS. The sensitivity and specificity of the ECG in predicting important complications were 54% and 58%, respectively. The rest and submaximal exercise RVG variables, the ECG, a history of MI, the location of the infarction, Killip class III, age, sex, and maximal work load performed were analyzed statistically to determine the best predictors of prognosis. The change with exercise in LVEF, ESV and the P/V index were most significant variables in predicting prognosis during the 6-month follow-up period. When patients with subsequent cardiac events were separated into those with death, recurrent MI and unstable or medically refractory angina as major cardiac events, and patients with persistent CHF and limiting angina as less important ("minor") cardiac events, only the peak submaximal exercise LVEF and history of MI were significant in distinguishing these groups. In patients without important cardiac events during the 3- and 6-month follow-up, 70% and 88%, respectively, no abnormality in the responses of LVEF, ESV, or P/V index to submaximal exercise. These results suggest that submaximal exercise testing with RVG is a highly sensitive means of classifying patients at the time of hospital discharge after MI according to the likelihood of having cardiac events during the ensuing 6 months.