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At least 721 records · Page 40Linked to original sources
PubMed2001

Quantification of regional contractile function after infarction: strain analysis superior to wall thickening analysis in discriminating infarct from remote myocardium.

OBJECTIVES: Using two-dimensional wall thickening (WT) (expressed as percentage) and strain analysis, regional contractile myocardial function was quantified and compared in 13 control subjects and 13 patients with a first myocardial infarction (MI). The findings in the patient group were related to global ventricular function and infarct size. BACKGROUND: In patients with coronary artery disease, regions with dysfunctional myocardium cannot be differentiated easily from regions with normal function by planar WT analysis. Physiologic factors, in combination with limitations of conventional imaging techniques, affect the calculation of WT. Quantitative assessment of contractile function by magnetic resonance (MR) tissue tagging and strain analysis may be less affected by these factors. METHODS: Two-dimensional regional WT and strain were calculated in three short-axis MR cine and tagged images, respectively. Left ventricular volumes and ejection fraction (EF) were obtained from a series of contiguous short-axis cine images. RESULTS: In patients with infarct-related ventricles, WT and strain analysis both revealed reduced myocardial function, as compared with control subjects (p < 0.005 and p < 0.001, respectively). However, WT analysis yielded no significant regional differences in function between infarct-related and remote myocardium (p = 0.064), whereas strain analysis did (p < 0.005). For detecting dysfunctional myocardium of electrocardiographically and angiographically defined infarct areas, WT analysis had a sensitivity of 69% and a specificity of 92%, whereas strain analysis demonstrated a sensitivity of 92% and a specificity of 99%. The EF correlated with WT (r = 0.76, p < 0.005) and strain (r = 0.89, p < 0.001). CONCLUSIONS: Two-dimensional strain analysis is more accurate than planar WT analysis in discriminating dysfunctional from functional myocardium, and it provides a strong correlation between regional myocardial and global ventricular function.

Aged↗
PubMed2001

Pre-infarction angina elicits greater myocardial viability on reperfusion after myocardial infarction: a dobutamine stress echocardiographic study.

OBJECTIVES: We sought to evaluate myocardial viability (inotropic reserve) after myocardial infarction (MI) and its relationship with the presence of unstable pre-infarction angina (PIA). BACKGROUND: Several studies have suggested that PIA can limit infarct size, but it is not known whether PIA can elicit myocardial viability after an acute MI, with left ventricular function improvement. METHODS: Before discharge from the hospital, 91 patients with a reperfused MI (either fibrinolysis or primary coronary angioplasty) had low-dose dobutamine echocardiography performed to assess the myocardial inotropic reserve of the infarct-related area. RESULTS: Twenty-nine patients (31.9%) had PIA in the 24-h period before the onset of MI. Nine patients were treated with primary coronary angioplasty: five (8.1%) in the group with PIA and four (13.8%) in the group without PIA. There were no other significant differences in the baseline characteristics of the patients. There were more viable segments in patients with PIA (44.9% vs. 30.7%, p = 0.007), and the number of patients with significant viability was higher in the PIA group (73.9% vs. 46.3%, p = 0.026). This occurred despite a similar number of segments with segmental wall abnormalities at baseline in both groups (46.1% vs. 46.9%, p = NS). CONCLUSIONS: The presence of previous unstable PIA induces greater myocardial viability of the infarct-related area upon reperfusion and, as such, could have considerable therapeutic and clinical implications.

Aged↗
PubMed1984

Electrocardiographic changes of acute lateral wall myocardial infarction: a reappraisal based on scintigraphic localization of the infarct.

To determine how often acute lateral myocardial infarcts may be electrocardiographically "silent," a new approach was utilized in which subjects were selected by admission thallium scintigraphy. Thirty-one patients with their first infarction were identified with moderate to severe perfusion defects of the lateral and posterolateral walls, persistent over 7 days and associated with severe wall motion abnormalities. Patients with involvement of the anterior, septal or "inferior" regions were not included. In nine patients, the perfusion defect extended to the anterolateral wall: all developed ST elevation and Q waves in at least one of the "lateral" leads (I, aVL or V6) but none showed changes in the "inferior" leads (II, III or aVF). In the other 22 patients, the perfusion defect was limited to the lateral and posterolateral walls: only 12 showed ST elevations (inferior leads only in 7, lateral leads only in 2, both leads in 3) and only 9 developed Q waves (inferior in all). In 8 of these 22 patients, the infarct was silent in the sense that no ST segment elevation or Q waves were seen, although ST depressions or T wave inversions, or both, in all but one patient were compatible with subendocardial infarction. The results indicate that the standard electrocardiogram is insensitive to changes in the lateral and posterolateral regions. Additional diagnostic studies are needed for proper localization and sizing of acute myocardial infarcts.

Adult↗
PubMed1987

Coronary angioplasty after recombinant tissue-type plasminogen activator in acute myocardial infarction: a report from the Thrombolysis in Myocardial Infarction (TIMI) Trial.

To assess the utility of percutaneous transluminal coronary angioplasty after successful thrombolytic therapy for patients with acute myocardial infarction, the outcome of 201 patients who received intravenous recombinant tissue-type plasminogen activator (rt-PA) was analyzed. Reperfusion of the infarct-related artery was observed in 132 patients who were assessed for potential coronary angioplasty at 18 to 48 hours after treatment. Coronary angioplasty was performed in 52 patients (39%). Reasons for not performing angioplasty included unsuitable coronary anatomy, presence of residual stenosis of less than 60% and the need to perform an earlier procedure. When attempted, coronary angioplasty was successful in 96% of patients and was associated with a decrease in coronary stenosis from 85 to 30%. No patient experienced a major complication associated with coronary angioplasty. Of 36 patients undergoing predischarge coronary angiography after successful angioplasty, the infarct-related artery remained patent in 97.2%. Thus, coronary angioplasty is feasible and safe in patients who achieve coronary reperfusion after intravenous rt-PA for acute myocardial infarction. Not all patients who achieve reperfusion, however, are suitable for coronary angioplasty. When attempted, angioplasty is usually successful and associated with sustained patency of the infarct-related artery.

Angioplasty, Balloon↗
PubMed1997

A prospective, randomized evaluation of prophylactic intraaortic balloon counterpulsation in high risk patients with acute myocardial infarction treated with primary angioplasty. Second Primary Angioplasty in Myocardial Infarction (PAMI-II) Trial Investigators.

OBJECTIVES: A large, international, multicenter, prospective, randomized trial was performed to determine the role of prophylactic intraaortic balloon pump (IABP) counterpulsation after primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI). BACKGROUND: Previous studies have suggested that routine IABP use after primary PTCA reduces infarct-related artery reocclusion, augments myocardial recovery and improves clinical outcomes. METHODS: Cardiac catheterization was performed in 1,100 patients within 12 h of onset of AMI at 34 clinical centers. Clinical and angiographic variables were used to stratify patients undergoing primary PTCA into high and low risk groups. High risk patients were then randomized to 36 to 48 h of IABP (n = 211) or traditional care (n = 226). The study had 80% power to detect a reduction in the primary end point from 30% to 20%. RESULTS: There was no significant difference in the predefined primary combined end point of death, reinfarction, infarct-related artery reocclusion, stroke or new-onset heart failure or sustained hypotension in patients treated with an IABP versus those treated conservatively (28.9% vs. 29.2%, p = 0.95). The IABP strategy conferred modest benefits in reduction of recurrent ischemia (13.3% vs. 19.6%, p = 0.08) and subsequent unscheduled repeat catheterization (7.6% vs. 13.3%, p = 0.05) but did not reduce the rate of infarct-related artery reocclusion (6.7% vs. 5.5%, p = 0.64), reinfarction (6.2% vs. 8.0%, p = 0.46) or mortality (4.3% vs. 3.1%) and was associated with a higher incidence of stroke (2.4% vs. 0%, p = 0.03). IABP use did not result in enhanced myocardial recovery as assessed by paired admission to predischarge and 6-week rest and exercise left ventricular ejection fraction. CONCLUSIONS: In contrast to previous studies, a prophylactic IABP strategy after primary PTCA in hemodynamically stable high risk patients with AMI does not decrease the rates of infarct-related artery reocclusion or reinfarction, promote myocardial recovery or improve overall clinical outcome.

Angioplasty, Balloon, Coronary↗
PubMed2000

Detection of residual tissue viability within the infarct zone in patients with acute myocardial infarction: ultrasonic integrated backscatter analysis versus dobutamine stress echocardiography.

OBJECTIVES: The goals of this study were to analyze temporal changes in cardiac cyclic variation of integrated backscatter (CVIB) in acute myocardial infarction (AMI) and to investigate the predictive value of CVIB normalization compared with that of dobutamine stress echocardiography (DSE) in the assessment of functional recovery after revascularization. BACKGROUND: The normal CVIB is blunted by ischemia and recovers early after reperfusion, faster than wall motion improvement. Analysis of CVIB has been widely investigated for its potential to detect viable myocardium in the early stage of infarction. No studies have compared CVIB analysis with other techniques for viability assessment in patients with acute ischemic. METHODS AND RESULTS: Integrated backscatter images were obtained in 12 patients with AMI on days 1, 3, and 7 after admission and 1 month after revascularization. On day 7, DSE was performed in all patients. On admission, 22 of 144 segments were dyssynergic. On day 1, CVIB was abnormal in all 22 infarcted segments, on day 3, in 16, and on day 7, in only 10 infarcted segments. Eight of 10 segments nonviable by CVIB (CVIB-nonviable) were also nonrespondent by DSE; whereas 12 of 14 segments viable by DSE (DSE-viable) were also CVIB-viable. At follow-up, 10 CVIB-viable segments and 1 CVIB-nonviable segment showed functional recovery; whereas 10 of 14 DSE-viable segments showed functional recovery. Thus the positive predictive value of CVIB and DSE was 83% and 72%, respectively, with a diagnostic agreement between techniques in 77% of segments. CONCLUSIONS: Our data suggest that the normalization in CVIB in the first week after AMI accurately predicts residual tissue viability within the infarct zone. We also observed that the initial pattern of cyclic variation may be predictive of functional recovery. Finally, we found a good correlation between the recovery of a normal CVIB in segments that were still dysfunctional and a more validated method to assess tissue viability, such as the dobutamine test.

Adult↗
PubMed1996

Late seizures following a first symptomatic brain infarct are related to large infarcts involving the posterior area around the lateral sulcus.

Controversies exist concerning factors that contribute to the occurrence of epileptic seizures after stroke. Therefore, we studied prospectively the occurrence of seizures in 322 patients with a first-ever CT-confirmed symptomatic territorial brain infarct involving the cortex. We also studied potential risk factors for seizures, and gave special attention to cortical infarct location. Fifty-four patients developed post-stroke seizures. We distinguished between early- and late-onset seizures, occurring within two weeks following stroke-onset, or later than two weeks, respectively. We found that patients of 65 years or older with a cardioembolic brain infarct involving the middle temporal or post-central gyrus, had an almost eight times increased risk of early-onset seizures, whereas patients with a large brain infarct involving the supramarginal or superior temporal gyrus, had a five times increased risk of late-onset seizures. We conclude that risk factors and epileptogenic cortical areas for post brain infarct seizures can be identified, which however, differ between early- and late-onset seizures. These two seizure types may also differ in terms of seizure mechanism. Our findings may influence the decision on prophylactic treatment with antiepileptic drugs in stroke patients.

Adult↗
PubMed2002

Effects of early treatment with growth hormone on infarct size, survival, and cardiac gene expression after acute myocardial infarction.

OBJECTIVE: This study examined the effects of growth hormone (GH) on infarct size, survival, and cardiac gene expression in rats with acute myocardial infarction. DESIGN: Animals randomly received sc injection of either saline vehicle (n = 98) or GH (2mg/kg/day, n = 105) for 14 days commencing the day of left coronary artery ligation. Infarct size was determined by morphometric analysis at the time of death or at 52 weeks post-surgery. Gene expression was analyzed by real-time RT-PCR after 2-week treatment. RESULTS: GH decreased infarct size by 18% (P < 0.01) and increased survival by 36% at 52 weeks. GH also significantly reduced cardiac expression of atrial natriuretic factor, beta-myosin heavy chain, alpha-smooth muscle actin, collagen I, collagen III, fibronectin, and pro-inflammatory cytokines. CONCLUSIONS: Treatment with GH for 2 weeks beginning on the day of myocardial infarction produced beneficial effects that were associated with reductions in cardiac gene expression symptomatic of pathological remodeling.

Actins↗
PubMed1998

Short- and long-term effects of early fosinopril administration in patients with acute anterior myocardial infarction undergoing intravenous thrombolysis: results from the Fosinopril in Acute Myocardial Infarction Study. FAMIS Working Party.

BACKGROUND: Angiotensin-converting enzyme inhibitors are used in patients who have myocardial infarction with left ventricular (LV) dysfunction. Few data are available in patients whose LV function is within the normal range. METHODS AND RESULTS: The Fosinopril in Acute Myocardial Infarction Study was a 2-year, randomized, double-blind, placebo-controlled, multicenter study of 285 patients with anterior acute myocardial infarction and was designed to investigate the effects of the early (<9 hours) administration of fosinopril and thrombolysis on (1) changes in echocardiographically evaluated LV volumes at 3 months and (2) long-term occurrence of death and congestive heart failure. LV volumes were normal at baseline in more than 70% of patients and were comparable between groups both at baseline and after 3 months of treatment. Fosinopril-treated patients showed a 30% reduction in the 2-year combined prevalence of death or moderate-to-severe congestive heart failure (New York Heart Association class III-IV) despite having a worse clinical profile at baseline. The benefit of fosinopril was confirmed both in patients without congestive heart failure at admission and in those with ejection fraction >40% at baseline. Moreover, the incidence of significant ventricular arrhythmias was lower in the fosinopril group (0.8% vs 6.0%, p < 0.02). CONCLUSIONS: The results of the Fosinopril in Acute Myocardial Infarction Study suggest that early treatment with fosinopril can benefit patients with acute myocardial infarction in addition to a prevention of LV remodeling.

Aged↗
PubMed2000

[Comparison of acute myocardial infarct in the old and new lands of unified Germany, 1996-1998. Data of the Myocardial Infarct Register (MIR)].

BACKGROUND AND OBJECTIVE: Little is known about any differences in the prevention, treatment and treatment results of myocardial infarction between the "old" (western) and "new" (eastern) Lands (OFL vs. NFL) of the now unified Federal Republic of Germany. It was the aim of this study to determine any such differences. PATIENTS AND METHODS: The Myocardial Infarction Register (MIR) is a multicentre and prospective compilation of consecutive unselected data on patients with acute myocardial infarction sustained between December 1996 and May 1998. All date collected between these dates were included in the study: there were 14,608 patients in 211 hospitals, 5618 patients and 68 hospitals of those in the eastern part (former German Democratic Republic). The median age of the entire collective was 68 years, 35% of patients were female. RESULTS: There was a higher prevalence of risk factors in the NFL than the OFL: 43.3 vs. 39.0% with regard to arterial hypertension (p = 0.002), and 28.9 vs. 22.4% with regard to diabetes mellitus (p < 0.001). The prehospital period was longer in the NFL by an average of 30 min (210 vs. 180 min; p < 0.001. Another difference concerned the lower number of diagnostic ECGs in the NFL (61.8 vs. 68.6%; p < 0.001). There were no significant differences with regard to acute and discharge medication (acetylsalicylic acid, betablockers, angiotensin-converting-enzyme inhibitors and cholesterol-synthesis inhibitors). The frequency of primary recanalization treatment (thrombolysis or percutaneous transluminal coronary angioplasty) in patients with clear-cut indications for thrombolysis was higher in the OFL (85.1 vs. 74.5%; p < 0.001). Hospital mortality was comparable (15.1 vs. 15.9%; p = 0.14). CONCLUSION: Patient characteristics and treatment in the two parts of Germany were comparable in the two parts. Treatment of acute myocardial infarction attained a similarly high standard in both. But in both parts there is room for improving the application of guidelines for treating of myocardial infarction to routine clinical practice. Greater effort should be made to inform the population, especially of the NFL, about the need for primary prevention and reduction in prehospital time.

Adrenergic beta-Antagonists↗
PubMed1984

Reduction of infarct size with the early use of timolol in acute myocardial infarction.

One hundred forty-four patients admitted to the hospital within four hours after onset of symptoms of myocardial infarction were randomly assigned to either intravenous timolol treatment or to placebo. Timolol was given intravenously for the first 24 hours and orally thereafter for the duration of hospitalization. Infarct evolution was assessed by continuous vectorcardiography and creatine kinase release. The timolol group had reduced myocardial ischemia and infarct size as measured by an accelerated reduction of ST-vector magnitude, a significant reduction of maximal cumulative creatine kinase release (29.5 per cent), and significantly smaller changes in QRS-vector variables (20 to 25 per cent). Furthermore, the predicted creatine kinase release and maximal QRS-vector change for a given initial ST-vector magnitude was significantly reduced in the timolol group. Timolol was also associated with significant reductions in pain and need for analgesics and was well tolerated overall. This study supports the use of intravenous timolol in the early phase of suspected myocardial infarction to limit infarct size.

Administration, Oral↗
PubMed1999

Sex-based differences in early mortality after myocardial infarction. National Registry of Myocardial Infarction 2 Participants.

BACKGROUND: There is conflicting information about whether short-term mortality after myocardial infarction is higher among women than among men after adjustment for age and other prognostic factors. We hypothesized that younger, but not older, women have higher mortality rates during hospitalization than their male peers. METHODS: We analyzed data on 384,878 patients (155,565 women and 229,313 men) who were 30 to 89 years of age and who had been enrolled in the National Registry of Myocardial Infarction 2 between June 1994 and January 1998. Patients who had been transferred from or to other hospitals were excluded. RESULTS: The overall mortality rate during hospitalization was 16.7 percent among the women and 11.5 percent among the men. Sex-based differences in the rates varied according to age. Among patients less than 50 years of age, the mortality rate for the women was more than twice that for the men. The difference in the rates decreased with increasing age and was no longer significant after the age of 74 (P< 0.001 for the interaction between sex and age). Logistic-regression analysis showed that the odds of death were 11.1 percent greater for women than for men with every five-year decrease in age (95 percent confidence interval, 10.1 to 12.1 percent). Differences in medical history, the clinical severity of the infarction, and early management accounted for only about one third of the difference in the risk. After adjustment for these factors, women still had a higher risk of death for every five years of decreasing age (increase in the odds of death, 7.0 percent; 95 percent confidence interval, 5.9 to 8.1 percent). CONCLUSIONS: After myocardial infarction, younger women, but not older women, have higher rates of death during hospitalization than men of the same age. The younger the age of the patients, the higher the risk of death among women relative to men. Younger women with myocardial infarction represent a high-risk group deserving of special study.

Adult↗
PubMed2002

How long is too long? Association of time delay to successful reperfusion and ventricular function outcome in acute myocardial infarction: the case for thrombolytic therapy before planned angioplasty for acute myocardial infarction.

OBJECTIVES: The purpose of this study was to quantify the effect of time delays to reperfusion on ventricular function after myocardial infarction. This allows one to identify a group of patients in whom a strategy using antecedent pharmacologic reperfusion therapy before planned direct angioplasty may offer significant benefit. BACKGROUND: Direct angioplasty for myocardial infarction is associated with a high rate of successful reperfusion compared with pharmacologic reperfusion. However, there is an inherent time delay to treatment with angioplasty compared with pharmacologic therapy. There currently are insufficient data to determine the consequences of incremental time delays to reperfusion on ventricular function. METHODS: We determined, by logistic regression analysis, the probability of observing a decrement in postmyocardial infarction ventricular function as a function of incremental time delays to reperfusion. RESULTS: Time delays of 30, 60, 90, or 120 minutes to reperfusion increased the likelihood of a worse ventricular function outcome by 1.1-, 1.3-, 1.5-, and 1.7-fold, respectively (P <.02). The upper 95% confidence limits around these odds ratios are as high as 1.3 or 2.7 for 30- and 120-minute delays, respectively. Time from symptom onset to patency remained a significant determinant of ventricular function after adjustment for clinical and procedural factors. CONCLUSIONS: Delay in time to reperfusion, measured in minutes, results in significant loss of ventricular function after myocardial infarction. Interventional strategies designed for treatment of myocardial infarction when "door-to-balloon" time is expected to exceed 60 minutes should strongly consider incorporation of pharmacologic reperfusion therapy into the therapeutic paradigm.

Acute Disease↗
PubMed1997

The 60 minutes myocardial infarction project. Treatment and clinical outcome of patients with acute myocardial infarction in Germany.

AIMS: To describe patient characteristics, pre-hospital delay, treatment, complications and outcome in patients with acute myocardial infarction admitted to hospitals in Germany. METHODS AND RESULTS: The study was of prospective observational multicentre design. Those involved were consecutive patients with acute Q-wave myocardial infarction admitted within 96 h of onset of symptoms to 136 German hospitals between July 1992 and September 1994 (n = 14980, median age 66 (quartiles 57, 74) years, 68% male, 48% anterior wall infarction). Median pre-hospital delay was 170 (90, 475) min, with 17% arriving within the first hour and 61% within 4 h of onset of symptoms. The following patient groups had a short pre-hospital delay: males, those aged less than 65 years, those admitted at night or the weekend, those with a previous myocardial infarction, those in need of cardiopulmonary resuscitation, and those with a diagnostic first ECG. The first ECG was diagnostic in 67.6% of cases. Reperfusion therapy was used in 53%, with thrombolytic therapy in 51.6%. Median time from admission to initiation of treatment was 30 (20, 55) min. Respective rates of treatment with aspirin, nitrates, and beta-blockers were 81%, 83%, and 16%. Major complications were cerebral bleeding (0.4%), bleeding requiring transfusions (0.9%), left ventricular rupture (0.6%) and anaphylactic shock (0.1%). Median hospital stay was 20 (13, 26) days. In-hospital death rate was 17.2%. Increased hospital mortality was observed with female gender, an unknown or long pre-hospital delay, a diagnostic first ECG, anterior wall infarction, trauma or major operation within the last 14 days, renal insufficiency and malignoma. CONCLUSIONS: 'Real-life' hospital mortality is much higher than previously reported in clinical trials. To reduce hospital mortality, the efficacy of thrombolysis should be increased by shortening the pre-hospital delay, and the use of concomitant therapy, especially beta-blockers, should be increased.

Aged↗
PubMedDate not supplied

Hemodynamic effects of nifedipine in acute myocardial infarction with observations on infarct size.

To assess the safety of the slow calcium-channel blocker nifedipine in patients with acutely evolving myocardial infarction, hemodynamic effects of the drug were studied in 12 patients and infarct size was determined by enzymatic method in 14 patients presenting within 12 h of onset of pain. Nifedipine (3 doses of 20 mg given sublingually at 8-h intervals) produced a significant increase in heart rate and cardiac output accompanied by a fall in systemic arterial pressure and vascular resistance. These effects were sustained for a 24-h period of study. Despite an increase in heart rate and cardiac output, there was no worsening of symptoms or electrocardiographic evidence of myocardial ischemia. Assessment of infarct size did not reveal any differences between the control group and the patients who received nifedipine. We conclude that nifedipine may be safely given to patients with acute myocardial infarction. The drug may be usefully employed in patients with acute myocardial infarction accompanied by angina or hypertension.

Adult↗
PubMed1979

Mortality, arrhythmias and pump failure in acute myocardial infarction in relation to estimated infarct size.

Serial estimations of total serum creatine kinase (S-CK) were made in 194 consecutive patients with acute myocardial infarction (AMI). By itself, the maximum CK value could not separate patients in terms of high and low mortality but when the maximum CK value was related to age for patients with and without a history of previous AMI, two subgroups became apparent, one with 46% mortality (high-risk group) and another with 6% (low-risk group) during the hospital stay plus the next 90 days. In 114 of the patients, infarct size could be calculated. A good correlation was found between maximum CK and calculated infarct size (r = 0.93). Calculated infarct size alone could not distinguish between high and low mortality but when it was related to age for patients with and without a history of previous AMI, two subgroups emerged, one with 43% mortality and another with 3% during the hospital stay plus the next 90 days. The incidence of ventricular tachycardia during the stay in the Coronary Care Unit did not differ between the two risk groups separated either by maximum CK value or calculated infarct size. However, the incidence of shock and severe left heart failure during the acute phase was higher in the high-risk groups.

Acute Disease↗
PubMed1986

Experimental study on size-limitation of myocardial infarct in swine produced by a coronary balloon-catheterization. I. Preliminary report; morphometry of infarct size.

Experimental myocardial infarction was produced in 15 subject swine using a balloon catheter to occlude the left anterior descending coronary artery (LAD). After 30 minutes obstruction, the LAD was reperfused, and then the animals were sacrificed at 3 hours, 6 hours, 24 hours, and 48 hours after the onset of coronary occlusion, respectively. During and after the experiment they were investigated physiologically and pathomorphologically to measure the size of myocardial infarct, and the obtained results are as follows; Experimentally produced myocardial infarcts could be detected histopathologically by routine gross and light-microscopical means in the group which had suffered from ischemia for over 24 hours till sacrifice. Ischemic areas could not be distinguished from normal areas of the myocardium by routine techniques, but could be identified enzyme-histochemically in the groups observed for less than 6 hours. The mean weight ratio of infarcted myocardium to total ventricular myocardium was 25 +/- 3.6%. This method was useful for measuring infarct size.

Animals↗
PubMed2004

Myocardial SPECT perfusion defect size compared to infarct size by delayed gadolinium-enhanced magnetic resonance imaging in patients with acute or chronic infarction.

BACKGROUND: Single photon emission computed tomography (SPECT) perfusion imaging has been considered a reference method for non-invasive estimation of infarct size in man. Recently, delayed gadolinium-enhanced magnetic resonance imaging (DE-MRI) has evolved as an accurate tool to quantify infarct size. Therefore, the present study was designed to compare perfusion defect size by SPECT to hyperenhanced volume by DE-MRI. METHODS: DE-MRI was performed in 30 patients. Fourteen were patients with revascularized first-time acute infarctions, eight revascularized chronic infarctions, and eight clinically referred non-revascularized patients. SPECT was performed in the same patients and analysed by a commercial package. RESULTS: The hypoperfused volume by SPECT was larger than the hyperenhanced volume by DE-MRI by 8 +/- 8 ml (6% +/- 5 percentage points), 10 +/- 18 ml (6% +/- 11 percentage points), and 26 +/- 30 ml (12% +/- 10 percentage points) in the acute, chronic and clinical populations, respectively. Left ventricle wall volume was smaller by SPECT in all settings. CONCLUSION: The SPECT perfusion defect size was comparable with but generally slightly larger than the hyperenhanced volume by DE-MRI in both absolute and relative terms in patients with acute and chronic infarction. The results may be related to systematic differences between modalities but could also be influenced by biological phenomena such as wall thinning or hypoperfused but viable myocardium.

Acute Disease↗