Left Ventricular Function in Acute Myocardial Infarction Evaluated by Gated Scintiphotography

SUMMARY 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 > 1000 IU/l, 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.PATIENTS with acute myocardial infarction admitted in pulmonary edema or cardiogenic shock are at a high risk for early death. Those who demonstrate lesser degrees of hemodynamic compromise, in clinical class I or II, have a much better prognosis as a

Section: Clinical Outcomementioning

confidence: 99%

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

Becker¹,

Silverman²,

Bulkley³

et al. 1983

“…Since scintigraphic defect size was related to prognosis after AMI, it was not surprising that there was no significant difference between scintigraphic abnormalities in those with and those without prior infarction within diagnostic prognostic subgroups. Although more patients with prior infarction had larger abnormalities and a poorer prog-nosis than patients without prior infarction, there was also no difference in the size of scintigraphic abnormalities between those with and without prior infarction ( 24 where a high LVEF early after infarction was related with great reliability to a favorable outcome but a low LVEF was related to a variable prognosis.…”

Section: Scintigraphic Parameters and Mortalitymentioning

confidence: 90%

“…22,23 Several investigators have reported promising results using scintigraphic variables as prognostic indicators of AMI. Rigo et al 24 and Schelbert et al 1' found that a normal scintigraphic left ventricular ejection fraction (LVEF) early after AMI predicted survival. The extent and intensity of the abnormality on infarct scintigraphy have also been correlated with morbidity and mortality after AMI.…”

mentioning

confidence: 99%

The late prognostic value of acute scintigraphic measurement of myocardial infarction size.

Perez-Gonzalez¹,

Botvinick²,

Dunn³

et al. 1982

SUMMARY Infarct, perfusion and blood pool scintigraphy were performed in 62 patients during hospitalization for acute myocardial infarction. The largest measured infarct or perfusion image defect and left ventricular ejection fraction were related to the late prognosis determined a mean of 16 months after the event.Breakpoint values for all scintigraphic variables could separate those who were asymptomatic on followup from those who died. The A search for simple and accurate indicators of prognosis after AMI has been prompted by the unreliability of clinical findings,18 the invasive nature of hemodynamic measurements, and the lack of reproducibility of enzymatic determinations of infarct size. 19 Recently, technetium-99m pyrophosphate (99mTc-PYP) infarct scintigrams and rest thallium-201 (207T1) myocardial perfusion scintigrams were shown to correlate well with pathologic measurements of acute infarct size in dogs20 21 and in humans. 22,23 Several investigators have reported promising results using scintigraphic variables as prognostic indicators of AMI. Rigo et al.24 and Schelbert et al.1' found that a normal scintigraphic left ventricular ejection fraction (LVEF) early after AMI predicted survival. The extent and intensity of the abnormality on infarct scintigraphy have also been correlated with morbidity and mortality after AMI.25 26 Recently, scintigraphic perfusion defect size measured early in patients in Killip class I and II was shown to be the best predictor of early and late mortality in patients with AMI.27In the current study, we sought to determine the value of scintigraphic indicators of infarct size and left ventricular function in predicting the late clinical course of patients after AMI. For this purpose, a quantitative analysis of 99mTc-PYP infarct scintigrams, 201T1 perfusion scintigrams, and equilibrium gated blood pool scintigrams was performed during the initial hospitalization in a population of patients admitted with AMI and was correlated with the clinical course of patients during follow-up after hospital discharge. Methods PatientsHistorical features, including the presence of prior infarction, and electrocardiographic, enzymatic and scintigraphic studies, were evaluated in 62 patients admitted to the coronary care unit with AMI. Fifty-one (82.3%) were males, mean age 69 years (range 52-81 years). The diagnosis of AMI was based on at least two of the following criteria: a history of typical, prolonged

“…[35][36][37][38][39][40][41][42][43][44][45][46] Most studies have compared hemodynamic values obtained during the first days of the infarct to those obtained at later follow-up. These studies generally have indicated that improvement in cardiac performance may occur gradually in the majority of the surviving patients.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous changes in left ventricular function over the first 24 hours of acute myocardial infarction: implications for evaluating early therapeutic interventions.

Wackers¹,

Berger²,

Weinberg³

et al. 1982

SUMMARY The spontaneous changes in left ventricular ejection fraction (LVEF) during the first 24 hours of a first transmural infarction were assessed in 34 patients by serial gated cardiac blood pool imaging. Major therapeutic interventions with a view to limit infarct size were not used. Four determinations of LVEF were performed. Study 1 was performed as soon as possible after admission to the hospital. Studies 2 and 3 were performed 2 and 4 hours, respectively, after study 1. Tlwenty-four patients (70%) had study I within 6 hours after the onset of acute chest pain and 10 had it 6-12 hours after the onset of chest pain. Study 4 was performed 24 hours after the onset of chest pain. Compared with study 1, 19 of 34 patients (56%) had spontaneous changes in LVEF in at least one of the subsequent studies, exceeding the expected variability in stable patients. The changes ranged from a 32% increase to 14% absolute decrease. LVEF improved in 11 patients and deteriorated in eight. These spontaneous changes in left ventricular performance indicate that a single assessment of LVEF during the early hours of transmural myocardial infarction may not properly characterize cardiac performance in an individual patient and may not be the most appropriate reference against which to compare subsequent evolution of left ventricular function. These data may have implications for studies of the effects of early therapeutic interventions on LVEF.IN EXPERIMENTAL MODELS of infarction, ischemic myocardium can be salvaged by interventions that improve the balance between myocardial oxygen supply and demand. [1][2][3][4][5][6] However, such clear-cut therapeutic benefit in human myocardial infarction has not been demonstrated.7 -3 One reason for this may be limitations in the techniques suitable for objective documentation of myocardial salvage in man. Recently, radionuclide techniques such as multigated cardiac blood pool imaging have been proposed for noninvasive assessment of global cardiac performance at the patient's bedside, thereby providing functional estimates of myocardial salvage. However, little is known about the spontaneous evolution of left ventricular (LV) performance during the early hours of acute infarction. It is during the first 6-12 hours that interventions probably will have their greatest therapeutic impact. In order for these measurements to be applied to this patient population, their variability during this period must be established. Thus, we performed serial assessment of LV ejection fraction (LVEF) using gated cardiac blood pool imaging during the first 24 hours of acute transmural myocardial infarction in a group of patients in whom major therapeutic interventions were not used. Our All patients underwent bedside serial multigated equilibrium cardiac blood pool imaging studies. Study 1 was performed as soon as possible after arrival in the coronary care unit. Twenty-four (70%) of the 34 patients had the first multigated cardiac blood pool study performed within 6 hours (range 3-6 hours) after the onset o...