Scintigraphically detected predominant right ventricular dysfunction in acute myocardial infarction: clinical and hemodynamic correlates and implications for therapy and prognosis

To determine the clinical and hemodynamic correlates as well as therapeutic and prognostic implications of predominant right ventricular dysfunction complicating acute myocardial infarction, 43 consecutive patients with scintigraphic evidence of right ventricular dyssynergy and a depressed right ventricular ejection fraction (less than 0.39) in association with normal or near normal left ventricular ejection fraction (greater than or equal to 0.45) were prospectively evaluated. All 43 patients had acute inferior infarction, forming 40% of patients with acute inferior infarction, and only eight (24%) had elevated jugular venous pressure on admission. On hemodynamic monitoring, 74% of patients had a depressed cardiac index (less than or equal to 2.5 liters/min per m2), averaging 2.0 +/- 0.05 for the group. Of these, 30% did not demonstrate previously described hemodynamic criteria of predominant right ventricular infarction (right atrial pressure greater than or equal to 10 mm Hg or right atrial to pulmonary capillary wedge pressure ratio greater than or equal to 0.8, or both). The left ventricular end-diastolic volume was reduced to 49 +/- 11 ml/m2 (n = 22) and correlated significantly with the stroke volume index (r = 0.82; p less than 0.0001) and cardiac index (r = 0.57; p = 0.005). The follow-up right ventricular ejection fraction, determined in 33 patients, showed an increase of 10% or greater in 26 (79%), increasing from a mean value of 0.30 +/- 0.06 to 0.40 +/- 0.09 (p less than 0.0001) without a significant overall change in the mean left ventricular ejection fraction (0.56 +/- 0.10 to 0.56 +/- 0.11, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences in left ventricular function between anterior and inferior myocardial infarction of equivalent enzymatic size

The reasons for the poorer prognosis of anterior versus inferior myocardial infarction of equivalent enzymatic size remain uncertain. We investigated whether there are differences in left ventricular function between patients with anterior and inferior infarctions of equivalent enzymatic size to account for their differing outcomes. Clinical, serum enzyme, and electrocardiographic data were prospectively recorded in a consecutive series of patients less than 70 years of age with their first myocardial infarction. At 29 +/- 6 days following infarction, ejection fraction and left ventricular wall motion were assessed by gated heart scintigraphy and functional capacity by treadmill exercise testing in 19 patients with anterior and in 23 patients with inferior myocardial infarction. Peak creatine kinase and QRS scores were used to estimate total infarct size and left ventricular infarct size respectively. The anterior infarcts were of similar size to the inferior infarcts as determined by peak creatine kinase (1444 [mean] +/- 1161 [SD] U/L versus 1484 [mean] +/- 1182 [SD] U/L, respectively, P = 0.91) and peak aspartate transaminases (174 +/- 112 U/L versus 164 +/- 102 U/L, P = 0.78). The anterior myocardial infarct group had a greater percentage of the left ventricle infarcted on QRS scoring than the inferior infarct group (25.9 +/- 14.4% versus 11.1 +/- 6.0% respectively, P = 0.0004), lower global left ventricular ejection fraction (45.8 +/- 16% versus 54.6 +/- 9.2%, P = 0.04) and greater left ventricular regional wall abnormality. A significant negative correlation existed between left ventricular ejection fraction and peak creatine kinase for both groups, but was more marked with anterior infarction (r = -0.78, P less than 0.01) compared with inferior infarction (r = -0.49, P less than 0.05). Exercise-induced ST segment elevation was more frequent in the anterior than the inferior infarct group (59% versus 18%, P less than 0.02). However, both infarct locations had similar exercise tolerance, exercise-induced angina and ST segment depression. Despite equivalence of infarct size of the two infarct locations on enzyme testing, anterior infarction was associated with greater abnormality of left ventricular function with lower resting global left ventricular ejection fraction; greater resting left ventricular regional wall abnormality and greater exercise-induced ST segment elevation. These differences probably contribute to the poorer prognosis of patients with anterior infarction compared to those with inferior infarction of equivalent enzymatic size, given the previously well-documented prognostic importance of left ventricular function.     

Involvement and function of the right ventricle in acute myocardial infarct. Hemodynamic, echocardiographic and angioscintigraphic correlations

To assess the acute effects of myocardial infarction on right ventricular function 22 patients were studied utilizing right heart catheterization, radionuclide angiography and two dimensional echocardiography. Thirteen patients had inferior myocardial infarction (Group I) and 9 anteroseptal or anterior (Group II). Hemodynamic findings suggesting right ventricular infarction were present in 3 patients of Group I. Mean radionuclide right ventricular ejection fraction was lower in inferior myocardial patients (38.2 +/- 7.6-Group I vs 50.3 +/- 11.4-Group II, p less than 0.005), while left ventricular ejection fraction in anteroseptal, and anterior myocardial infarction patients (36.8 +/- 10.5-Group II vs 55.9 +/- 7.6-Group I, p less than 0.001). Six patients in Group I presented a depressed radionuclide right ventricular ejection fraction (less than 40%): moreover right ventricular ejection fraction correlated with left ventricular ejection fraction in Group II (r = 0.79, p less than 0.001) but not in Group I (r = 0.55, p = NS). By mean of 2 dimensional echocardiography Group I patients had an increased right ventricular end diastolic area (15.3 +/- 3.8 vs 12.1 +/- 1.2 cm2, p less than 0.05) while Group II an increased right ventricular free wall motion (47.3 +/- 10.7 vs 32.4 +/- 14.1%, p less than 0.005); right ventricular end diastolic area correlated with right ventricular ejection fraction only in Group I (r = 0.60, p less than 0.05). Five patients in Group I and no patients in Group II had an enlarged right ventricular end diastolic area. Therefore, radionuclide and echocardiographic evidence of right ventricular involvement were not always associated with abnormal hemodynamics. Thus, the damaged right ventricular chamber dilates to allow an adequate stroke volume in presence of low ejection fraction; hemodynamic significant right ventricular myocardial infarction becomes evident only in patients with more severe right ventricular compromise; the increase in right ventricular free wall motion in anterior myocardial infarction patients compensates the loss of contribution of interventricular septum contraction.     

Assessment of right ventricular function in acute inferior myocardial infarction using 133-xenon imaging

The detection of right ventricular dysfunction in acute inferior myocardial infarction is important because of its potentially serious consequences which may be remediable with the appropriate therapeutic manoeuvres. A technique has been developed to assess right ventricular function using 133-xenon. This technique was applied to 26 patients who had sustained an acute inferior myocardial infarction. Right ventricular ejection fractions ranged from 7-54%, mean 30 +/- 11%, which was significantly lower than values obtained from normal volunteers (n = 21), mean 43 +/- 5%, and patients with arteriographically proven coronary artery disease without previous myocardial infarction (n = 12), mean 39 +/- 9%, P less than 0.001, and P less than 0.001, respectively. In the patients with acute inferior myocardial infarction 18 patients (69%) had evidence of right ventricular dysfunction (right ventricular ejection fraction less than 35%). 13/26 patients (50%) had clinical evidence of right ventricular dysfunction with a mean right ventricular ejection fraction 26 +/- 11% (range 7-54%) which was significantly lower than the patients without evidence of right ventricular dysfunction, mean 35 +/- 9% (range 16-49%), P less than 0.001. The clinical signs had a sensitivity of 72% (13/18), a specificity of 87.5% (7/8) and a predictive accuracy of 76% (20/26) when compared to the imaging data. In conclusion: (1) gated 133-xenon imaging provides a method for assessing right ventricular function in the setting of acute myocardial infarction; (2) a wide spectrum of right ventricular dysfunction occurs following inferior myocardial infarction which may not manifest itself clinically.     

Right ventricular systolic and diastolic function at rest in patients with coronary artery disease. Assessment with equilibrium radionuclide ventriculography

Right ventricular systolic and diastolic function was studied in patients with ischemic heart disease using equilibrium radionuclide ventriculography. In patients with inferior myocardial infarction and proximal right coronary lesions, the right ventricular ejection fraction (0.43 +/- 0.06, n = 10, mean +/- SD) and peak filling rate (1.7 +/- 0.4 EDV/sec) were lower than normals (0.57 +/- 0.07 and 2.7 +/- 0.4 EDV/sec, n = 10, p less than 0.001, respectively). In these patients, the right ventricular time to peak filling rate was longer than in normals (225 +/- 36 msec vs 136 +/- 45 msec, p less than 0.001), while the left ventricular ejection fraction remained normal. In patients with inferior myocardial infarction and distal right coronary lesions, the right ventricular ejection fraction, peak filling rate and time to peak filling rate were not different from those in normals. Even in patients with proximal right coronary lesions, the right ventricular ejection fraction was normal unless they had an inferior myocardial infarction. A decreased left ventricular ejection fraction and abnormal motion of the ventricular septum did not affect the right ventricular ejection fraction. The present results suggest that patients with an inferior myocardial infarction and proximal right coronary lesion often develop right ventricular systolic and diastolic dysfunction.     

Chronic effects of myocardial infarction on right ventricular function: a noninvasive assessment

To assess the chronic effects of myocardial infarction on right ventricular function, 48 subjects were studied utilizing radionuclide angiography and two-dimensional echocardiography. Ten were normal subjects (group I), 11 had previous inferior wall myocardial infarction (group II), 10 had previous anteroseptal infarction (group III), 11 had combined anteroseptal and inferior infarction (group IV) and 6 had extensive anterolateral infarction (group V). The mean (+/- standard deviation) left ventricular ejection fraction was 0.66 +/- 0.03 in group I, 0.58 +/- 0.02 in group II, 0.52 +/- 0.02 in group III, 0.33 +/- 0.03 in group IV and 0.33 +/- 0.01 in group V. No systematic correlation between left and right ventricular ejection fraction was observed among the groups. The mean right ventricular ejection fraction was significantly reduced in the presence of inferior myocardial infarction (0.30 +/- 0.03 in group II and 0.29 +/- 0.03 in group IV compared with 0.43 +/- 0.02 in group I [p less than 0.001]). The group II and IV patients also had increased (p less than 0.001) right ventricular end-diastolic area and decreased (p less than 0.001) right ventricular free wall motion by two-dimensional echocardiography. In the presence of anteroseptal infarction (group III), right ventricular free wall motion was increased (p less than 0.05) compared with normal subjects (group I). Thus, the effects of prior myocardial infarction on right ventricular function depend more on the location of infarction than on the extent of left ventricular dysfunction. Inferior infarction was commonly associated with reduced right ventricular ejection fraction and increased right ventricular end-diastolic area. The right ventricular free wall excursion was increased in the presence of anteroseptal infarction, suggested loss of contribution of interventricular septal contraction to right ventricular ejection.     

Right ventricular ejection fraction in patients with acute anterior and inferior myocardial infarction assessed by radionuclide angiography

We measured right and left ventricular ejection fracttion (EF) from high frequency time-activity curves obtained during the initial passage of an intravenous bolus of 99mTc (Sn) pyrophosphate. In 22 normal controls right ventricular EF averaged 0.52 +/- 0.04 (SD). In 24 acute anterior or lateral infarction patients right ventricular EF was normal (0.56 +/- 0.10), while left ventricular EF was reduced (0.45 +/- 0.10, P less than 0.001 vs controls). In 19 acute inferior infarction patients left ventricular EF also was depressed (0.51 +/- 0.09, P less than 0.001 vs controls). Among 7 of 19 inferior infarction patients with right ventricular by scintigraphy, right ventricular EF was reduced (0.39 +/- 0.05; P less than 0.001 vs normals; P less than 0.01 vs inferior infarction patients without right ventricular involvement). In the latter group right ventricular EF averaged 0.51 +/- 0.10 (NS vs normals). We conclude 1) a single injection of 99mTc (Sn) pyrophosphate can identify right and left ventricular dysfunction and infarct location in acute myocardial infarction, 2) right ventricular EF is well-preserved except when inferior infarction involves the right ventricle.     

Comparison of radionuclide and enzymatic estimate of infarct size in patients with acute myocardial infarction

A comparison was made of the estimated size of the myocardial infarction occurring in 26 patients with a first infarction using creatine kinase (CK) enzyme release between radionuclide gated blood pool measurement of total and regional ventricular function and thallium-201 scintigraphic measurement of myocardial perfusion defects. Creatine kinase estimates of infarct size (enzymatic infarct size) correlated closely with the percent of abnormal contracting regions, left ventricular ejection fraction and thallium-201 estimates of percent of abnormal perfusion area (r = 0.78, 0.69 and 0.74, respectively, p less than 0.01). A close correlation also existed between percent abnormal perfusion area and percent of abnormal contracting regions (r = 0.81, p less than 0.01) and left ventricular ejection fraction (r = 0.69, p less than 0.01). Enzymatic infarct size was larger in anterior (116 +/- 37 CK-g-Eq) than inferior (52 +/- 29 CK-g-Eq) myocardial infarction (p less than 0.01) and was associated with significantly more left ventricular functional impairment as determined by left ventricular ejection fraction (33 +/- 7 versus 60 +/- 10%) (p less than 0.01) and percent abnormal perfusion area (58 +/- 14 versus 13 +/- 12) (p less than 0.01). No significant correlation was observed between enzymatic infarct size and right ventricular ejection fraction. These different methods of estimating infarct size correlated closely with each other in these patients with a first uncomplicated myocardial infarction.     

Echocardiographic determinants of left ventricular ejection fraction after acute myocardial infarction

OBJECTIVE: This study was performed to determine if factors other than the size of regional dysfunction influence the global left ventricular ejection fraction after acute myocardial infarction. BACKGROUND: Left ventricular ejection fraction is an important prognostic variable after acute myocardial infarction. Although infarct size is known to affect the subsequent global left ventricular ejection fraction, it remains unclear whether other factors such as site or severity of the wall motion abnormality influence the ejection fraction after acute myocardial infarction. METHODS: Sixty-nine consecutive patients (mean age 61 +/- 14 years, 46 [67%] male) who did not receive thrombolytic therapy or undergo early revascularization were studied by echocardiography 1 week after Q-wave myocardial infarction. The absolute size of the region of abnormal wall motion (AWM) and the percentage of the endocardium involved (%AWM) were quantitated along with the wall motion score. A severity index was then derived as the mean wall motion score within the region of AWM. Site of myocardial infarction was classified as either anterior or inferior from the endocardial map. Left ventricular ejection fraction was measured by Simpson's method with 2 apical views. RESULTS: Twenty-nine (42%) patients had anterior and 40 had inferior myocardial infarction. The mean left ventricular ejection fraction was significantly lower in anterior than in inferior myocardial infarction (44.8% +/- 11.5% vs 53% +/- 8.6%; P =. 001). The mean %AWM was greater in anterior than in inferior myocardial infarction (32.1 +/- 15.5 vs 22.4 +/- 14.1; P =.01). The mean wall motion score was greater in anterior than in inferior myocardial infarction (9.8 +/- 6.4 vs 6.4 +/- 4.4; P =.01). The mean severity index did not differ by site. Multiple regression analysis demonstrated that, in descending order of importance, %AWM, extent of apical involvement, and site of myocardial infarction were independent determinants of global left ventricular ejection fraction. CONCLUSIONS: For myocardial infarctions of similar size, left ventricular ejection fraction is lower when apical involvement is extensive and the site of infarction is anterior. This site-dependent difference may be related to characteristics specific to the apex.     

Effect of coronary artery recanalization on right ventricular function in patients with acute myocardial infarction

The effects of coronary artery recanalization by intracoronary administration of streptokinase on left ventricular function during acute myocardial infarction have received increasing attention in recent years. Although myocardial dysfunction is often more pronounced in the right ventricle than in the left ventricle in patients with acute inferior wall myocardial infarction, the effect of coronary artery recanalization on right ventricular dysfunction has not been previously addressed. Accordingly, in this investigation, 54 patients who participated in a prospective, controlled, randomized trial of recanalization during acute myocardial infarction were studied. Among 30 patients with inferior wall infarction, 19 had right ventricular dysfunction on admission; 11 of these 19 had positive uptake of technetium-99m pyrophosphate in the right ventricle, indicative of right ventricular infarction. Patients with successful recanalization (n = 6) exhibited improved right ventricular ejection fraction from admission to day 10 (26 +/- 7 to 39 +/- 14%, p less than 0.03). However, control patients (n = 6) and patients who did not undergo recanalization (n = 7) also exhibited improvement (20 +/- 7 to 29 +/- 11% [p less than 0.02] and 30 +/- 8 to 40 +/- 6% [p less than 0.03], respectively). Improvement in several other variables of right ventricular dysfunction evolved at an equal rate with the ejection fraction changes. Patients with or without right ventricular infarction improved similarly. These data indicate that the right ventricular dysfunction commonly associated with inferior wall infarction is often transient, and improvement is the rule, irrespective of early recanalization of the "infarct vessel."     

Right ventricular function during the convalescence phase of posterior primary infarction

Right ventricular extension is very common in inferior myocardial infarction and the resulting haemodynamic changes are well documented. The aim of this prospective study was to assess the consequences on regional and global right ventricular function at a distance from the initial episode. The study population included 32 patients (29 men and 3 women; mean age 52.7 +/- 6 years) admitted consecutively to the coronary care unit for acute inferior wall myocardial infarction with right ventricular extension (group A: 14 patients) or without (group B: 18 patients), based on the initial haemodynamic data. All patients underwent right and left cardiac catheterisation with selective biplane right and left ventriculography and coronary angiography, 2.9 +/- 1 months after the acute episode. In group A, there was a normalisation of the haemodynamic changes observed during the acute phase of myocardial infarction, complete occlusion (10 cases) or a significant residual stenosis (3 cases) of the right coronary artery proximal or immediately distal to the right marginal artery and persistence of an alteration of global right ventricular systolic function when compared with group B (increased end systolic volume: RVESV = 43 +/- 11 ml/m2 vs 35 +/- 9 ml/m2, p less than 0.02, and a decreased ejection fraction: RVEF = 49 +/- 7 p. 100 vs 57 +/- 9 p. 100, p less than 0.01, resulting from hypokinesia or akinesia of the right ventricular inferior wall; mean shortening delta R = 11 +/- 6 p. 100 vs 17 +/- 7 p. 100, p less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)     

Two-dimensional echocardiographic estimation of right ventricular ejection fraction in patients with coronary artery disease

Two-dimensional echocardiographic determination of right ventricular ejection fraction was compared with right ventricular ejection fraction obtained by first pass radionuclide angiography in 39 patients with coronary artery disease. Apical four chamber and two chamber right ventricular views were obtained in 34 (87%) of the 39 patients, while a subcostal four chamber view was obtained in 31 patients (80%). Right ventricular ejection fraction by two-dimensional echocardiography was calculated by the biplane area-length and Simpson's rule methods using two paired orthogonal views and utilizing a computerized light-pen method for tracing the right ventricular endocardium. A good correlation (r = 0.74 to 0.78) was found between radionuclide angiographic and two-dimensional echocardiographic right ventricular ejection fraction for each method used. Patients with acute inferior myocardial infarction had the lowest right ventricular ejection fraction by radionuclide angiography and two-dimensional echocardiography (p less than 0.05 compared with patients with right coronary artery obstruction and no infarction). There were no differences in right ventricular ejection fraction between patients with acute and old inferior myocardial infarction by both techniques. No correlation was found between left and right ventricular ejection fraction by radionuclide angiography (r = 0.16). It is concluded that 1) right ventricular ejection fraction by two-dimensional echocardiography correlates well with radionuclide angiographic measurements and can reliably evaluate right ventricular function in coronary artery disease, 2) patients with inferior myocardial infarction have reduced right ventricular ejection fraction, and 3) changes in left ventricular ejection fraction do not directly influence right ventricular function.     

Function of the right ventricle in patients with mitral valve diseases

To investigate right ventricular function in mitral valve disease, biplane cineventriculograms of the right and left ventricle were performed in 96 patients-35 with mitral stenosis, 26 with mitral regurgitation, 12 with combined mitral valve disease, 14 with mitral stenosis and tricuspid regurgitation, and nine with mitral regurgitation and tricuspid regurgitation, compared to 18 normals (N). Right ventricular enddiastolic volume index was moderately elevated in patients with mitral stenosis and concomitant tricuspid regurgitation (111.6 +/- 35.3 ml/m2, no significance compared to N: 95.9 +/- 21.8 ml/m2) and with mitral regurgitation and tricuspid regurgitation (107.9 +/- 45.1 ml/m2, no significance compared to N). A reduced right ventricular ejection fraction (RVEF less than or equal to 50%) was found in 40 of the 96 patients. Right ventricular ejection fraction was frequently reduced in patients with mitral regurgitation and tricuspid regurgitation (46.7% +/- 15.1%) and significantly reduced in patients with combined mitral valve disease (45.0 +/- 17.6%, compared to N: 58.0 +/- 7.1%, p less than 0.01). No significant correlations were found between right ventricular ejection fraction and left ventricular enddiastolic volume or left ventricular ejection fraction in patients with mitral valve disease. Moreover, right ventricular ejection fraction did not correlate with systolic pulmonary artery pressure, mean pulmonary artery pressure or mean pulmonary capillary wedge pressure. Local wall motion (mean systolic shortening) was determined for the anterior, anteroapical, and inferior segment in the RAO-projection and for the right ventricular free wall in the LAO-projection. 63% of the patients (n = 25) with reduced right ventricular function (RVEF less than of equal to 50%) showed local wall motion abnormalities, preferably in the anterior segment of the RAO- projection (48%) and the right ventricular free wall (30%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical significance of "reciprocal" S-T segment depression in acute myocardial infarction. Relative contributions of infarct size and ischemia at a distance

The early electrocardiographic results in 100 patients surviving their first myocardial infarction who thereafter underwent serial radionuclide ventriculography were reviewed. Site of infarction was anterior in 46 and inferior in 54, with lateral extension in two patients. Those with "reciprocal" S-T segment depression of more than 1 mm in the acute phase (n = 53) sustained larger infarcts on the basis of enzyme criteria (mean peak serum creatine kinase, +/- SD, 2,203 +/- 1,271 versus 1,544 +/- 1,197 IU/liter, p less than 0.02), with a higher incidence of ventricular akinesis and dyskinesis. Reciprocal change was more common during inferior infarction (n = 33) than anterior infarction (n = 20). Despite equivalent peak enzyme levels following anterior and inferior infarction with reciprocal S-T depression (mean peak creatine kinase 2,330 versus 2,128, NS), there was marked sparing of left ventricular function in the latter group (mean left ventricular ejection fraction 0.31 +/- 0.14 versus 0.42 +/- 0.09, p less than 0.01). Of 17 patients who died within two years of infarction, 14 had reciprocal changes. Patients who died after anterior infarction with reciprocal changes (n = 5) had poor left ventricular function compared with those who died after inferior infarction (n = 9; left ventricular ejection fraction, +/- SD, 0.21 +/- 0.05 versus 0.38 +/- 0.11, p less than 0.01). One third of those recovering from inferior infarction with reciprocal changes subsequently had positive results on exercise testing, and of the nine patients who died, five had good left ventricular function (left ventricular ejection fraction 0.44 to 0.50). Infarct size and ventricular wall motion abnormality proved to be of major importance in the production of inferior reciprocal S-T change during anterior infarction, and subsequent mortality was related to poor left ventricular function. The proximity of the precordial leads to left ventricular myocardium may increase the detection of concomitant anterior ischemia during inferior infarction, and those who exhibit reciprocal change are presumably at risk from left main stem or anterior descending lesions but with reasonably good ventricular function represent a more attractive population for invasive investigation.     

Comparison of the influence of acute transmural and nontransmural myocardial infarction on ventricular function

In order to assess the relative impact on left and right ventricular function of nontransmural and transmural acute myocardial infarction (AMI), we performed radionuclide ventriculography in 86 patients (54 men and 32 women) within 16 hours after a first infarct. Nontransmural infarction was present in 19 patients (11 anterior and 8 inferior). Transmural infarction was found in 67 patients (30 anterior and 37 inferior). Left ventricular ejection fractions were higher (0.57 +/- .014 vs 0.46 +/- 0.14, p less than 0.005) and left ventricular end-systolic volume lower (29 +/- 11 vs 42 +/- 20 ml/m2, p = 0.013) in patients with nontransmural infarction compared to those with transmural infarction. Right ventricular ejection fraction also may have been different in the two groups (0.63 +/- 0.15 vs 0.55 +/- 0.13, p = 0.057). In patients with inferior infarction, left and right ventricular ejection fractions were similar in patients with nontransmural and transmural infarction (0.60 +/- 0.09 vs 0.55 +/- 0.10, p = 0.119 and 0.58 +/- 0.14 vs 0.51 +/- 12, p = 0.226). On the other hand, patients with anterior transmural infarction had lower left ventricular ejection fractions (0.36 +/- 0.12 vs 0.54 +/- 0.17, p = 0.003) but similar right ventricular ejection fractions (0.60 +/- 0.13 vs 0.66 +/- 0.14, p = 0.14) compared to those with nontransmural anterior infarction. In 29 additional patients with a history of previous infarction, no differences in any of the parameters studied were found between those with transmural and those with nontransmural infarcts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Predicting cardiac mortality after uncomplicated myocardial infarction by exercise radionuclide ventriculography and exercise-induced ST segment elevation.

In 183 consecutive patients with recent, uncomplicated myocardial infarction, the following variables were associated with 4-year cardiac death: haemodynamic decompensation with exercise (P = 0.01), left ventricular ejection fraction at rest (P = 0.004) and at peak exercise (P = 0.003), persistent ST segment elevation at rest in the area of infarction = (P = 0.004), exercise-induced ST segment elevation (P = 0.02), and late aneurysmal evolution (P = 0.01). Exercise left ventricular ejection fraction was the sole variable selected by Cox regression analysis as an independent predictor of cardiac death. In 40 patients with ST segment elevation at rest, left ventricular ejection fraction was 42 +/- 17% at rest and 40 +/- 18% at peak exercise, versus 52 +/- 12% and 52 +/- 14% in the remaining patients (both P less than 0.01). Among these 40, 16 (all with anterior infarction) also had exercise-induced ST segment elevation; their ejection fraction was 32 +/- 13% at rest, 30 +/- 13% during exercise, versus 53 +/- 15% and 53 +/- 15% in 129 patients with no ST segment elevation either at rest, or during exercise (both P less than 0.01). The 4-year risk of death was 20% in the former 40 patients, 36% in the latter 16, while in the complete absence of ST segment elevation, such risk was 3%. All 14 patients with ST segment elevation only during exercise were alive after 4 years: their left ventricular ejection fraction was 47 +/- 12% at rest, 45 +/- 13% with exercise. ST segment elevation was associated with late aneurysmal evolution but not with exercise-induced ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

The predictive value of ventricular function during exercise after a myocardial infarct]

To assess the prognostic value of exercise left ventricular function, and if this test improves the prognostic value of clinical data and exercise test, 146 patients (mean age 56 +/- 9 years) underwent rest and exercise radionuclide angiography, 10 days after myocardial infarction. During follow-up (mean 16 +/- 5 months), 32 patients had new coronary events: 5 died, 9 had a new myocardial infarction and the remaining 18 developed unstable angina (Class III-IV of the CCS classification). Patients with new coronary events had more frequently severe left ventricular failure (Killip III-IV) (15% vs 3%; p less than 0.05) and postinfarction angina (32% vs 9%; p less than 0.01) than their counterparts. There were no differences regarding rest ejection fraction between both groups of patients. Exercise ejection fraction increased significantly (50 +/- 14% to 56 +/- 16%, p less than 0.001), while there was no change in patients with new coronary events (46 +/- 16% to 43 +/- 15%, NS). Logistic regression analysis including only clinical data identified postinfarction angina (p less than 0.01) and left ventricular failure (Killip III-IV) (p less than 0.01) as independent predictors of new coronary events. The sensitivity and specificity of the regression equation obtained with clinical data were 43% and 90%, respectively. Analyzing data from clinical variables, as well as exercise test and both, rest and exercise radionuclide angiography, logistic regression analysis identified, exercise ejection fraction (p less than 0.001), postinfarction angina (p less than 0.01) and rest ejection fraction (p less than 0.05) as independent predictors of new coronary events.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamically important right ventricular infarction: follow-up evaluation of right ventricular systolic function at rest and during exercise with radionuclide ventriculography and respiratory gas exchange

The prognosis and recovery of right ventricular systolic function in patients with hemodynamically documented right ventricular myocardial infarction (RVMI) is unclear. Therefore 27 patients who met hemodynamic criteria for RVMI were followed for at least 1 year. Four patients died within 1 year and 23 survived. Postmortem examination performed in three of the four patients showed extensive infarction of the right and left ventricles. Survivors underwent early and late follow-up resting radionuclide ventriculograms and late exercise studies. During long-term follow-up (1 to 4 years) resting radionuclide ventriculography demonstrated a significant improvement in right ventricular ejection fraction (30 +/- 7% to 43 +/- 8%; p less than .001) and right ventricular wall motion index (2.2 +/- 0.4 to 1.5 +/- 0.5; p less than .001) in 18 patients who survived longer than 1 year. Fourteen of these patients underwent upright bicycle exercise while off beta-blocking drugs and peak radionuclide ejection fraction was acquired after anaerobic threshold was achieved. Right ventricular ejection fraction increased significantly from 41 +/- 10% to 47 +/- 12% (p less than .001), as did the left ventricular ejection fraction (55 +/- 15% to 60 +/- 12%; p less than .05). The direction and magnitude of change of the right ventricular ejection fraction correlated significantly with the left ventricular ejection fraction (r = .82, p less than .02). Deviations from this correlation occurred in patients who had a decreased forced expiratory volume in 1 sec and an abnormal ventilatory reserve during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular function in acute myocardial infarction: assessment by nuclear angiography

Left ventricular function was assessed in 38 patients two to six days after acute myocardial infarction using nuclear angiocardiography and the following parameters were measured: Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV), ejection fraction (LVEF), indices of left ventricular filling and emptying, right ventricular ejection fraction and ejection rate. Their clinical significance was assessed by their relationship to the patients site and size of infarction, functional capacity, morbidity and mortality. The most sensitive indices of depressed left ventricular function were the EF and ESV. Thus, function was preserved in patients with a small inferior infarction (LVEF = 0.57 +/- 0.07, LVESV = 69 +/- 14 ml) and in Killip Class I (LVEF = 0.48 +/- 0.13, LVESV = 80 +/- 20 ml). Function was disturbed most in patients with extensive anterior infarction (LVEF = 0.18 +/- 0.12, LVESV = 131 +/- 46 ml), Killip Class IV (LVEF = 0.13 +/- 0.07, LVESV = 160 +/- 35 ml), cardiogenic shock (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 35 ml), pulmonary edema (LVEF = 0.11 +/- 0.06, LVESV = 166 +/- 25 ml) and pulmonary capillary wedge pressure greater than 20 mm Hg (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 33 ml). Previous infarction was associated with LV dilatation and a greater LVEDV. A lower ejection fraction signified a large infarct and poor left ventricular function. If the ejection fraction was less than 0.15, the patients were unlikely to leave the hospital alive, or if less than 0.25, they were left with poor residual ventricular function and either had significant cardiac failure or high late mortality. Nuclear angiocardiography was a simple method of predicting the clinical pattern and prognosis in each patient and emphasized the importance of limiting infarct size in acute myocardial infarction.     

Early recovery of left ventricular function after thrombolytic therapy for acute myocardial infarction: an important determinant of survival

Thrombolytic therapy for acute myocardial infarction reduces early mortality, but full recovery of left ventricular function after reperfusion is delayed. Therefore, the relations among reperfusion, survival and the time course of left ventricular functional recovery were examined in 226 patients treated with intracoronary streptokinase; 77% (134 patients) had sustained reperfusion and 31 patients had no reperfusion or had reocclusion by day 3. Wall motion was measured from contrast ventriculograms performed in the acute period and 3 days later in the central and peripheral infarct regions and the noninfarct region by the centerline method in 165 patients. Patients with reperfusion had better survival (p less than 0.05, mean follow-up 4.5 years) and a higher ejection fraction at 3 days (52 +/- 12 versus 46 +/- 10%, p less than 0.02) attributable to a significantly different change in peripheral infarct region function between the acute and 3 day studies (0.1 +/- 1.0 versus -0.3 +/- 0.9 SD, p less than 0.05). These early functional changes were significant in patients with anterior myocardial infarction and showed similar trends in those with inferior myocardial infarction. On Cox regression analysis, function measured at 3 days was more predictive of survival than was function measured acutely (chi square for acute ejection fraction = 11.48 versus 24.59 at 3 days). Although, as previously reported, greater than 45% of total recovery of left ventricular function occurs later, the ejection fraction achieved by day 3 is already predictive of survival. Thus, the mechanism by which successful thrombolytic therapy enhances survival is improvement of regional and global left ventricular function early after acute myocardial infarction.