Quantitative analysis of infarct size, contraction band necrosis, and coagulation necrosis in human autopsied hearts with acute myocardial infarction after treatment with selective intracoronary thrombolysis

Effects of Contact Force on Lesion Size During Pulsed Field Catheter Ablation: Histochemical Characterization of Ventricular Lesion Boundaries

BACKGROUND

Effects of contact force (CF) on lesion formation during pulsed field ablation (PFA) have not been well validated. The purpose of this study was to determine the relationship between average CF and lesion size during PFA using a swine-beating heart model.

METHODS

A 7F catheter with a 3.5-mm ablation electrode and CF sensor (TactiCath SE, Abbott) was connected to a PFA system (CENTAURI, Galvanize Therapeutics). In 5 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and a skin patch at 40 separate sites in right ventricle (28 Amp) and 55 separate sites in left ventricle (35 Amp) with 4 different levels of CF: (1) low (CF range of 4-13 g; median, 9.5 g); (2) moderate (15-30 g; median, 21.5 g); (3) high (34-55 g; median, 40 g); and (4) no electrode contact, 2 mm away from the endocardium. Swine were sacrificed at 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining. In 1 additional swine, COX (cytochrome c oxidase) staining was performed to examine mitochondrial activity to delineate reversible and irreversible lesion boundaries. Histological examination was performed with hematoxylin and eosin and Masson trichrome staining.

RESULTS

Ablation lesions were well demarcated with triphenyl tetrazolium chloride staining, showing (1) a dark central zone (contraction band necrosis and hemorrhage); (2) a pale zone (no mitochondrial activity and nuclear pyknosis, indicating apoptosis zone); and a hyperstained zone by triphenyl tetrazolium chloride and COX staining (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). At constant PFA current intensity, lesion depth increased significantly with increasing CF. There were no detectable lesions resulting from ablation without electrode contact.

CONCLUSIONS

Acute PFA ventricular lesions show irreversible and reversible lesion boundaries by triphenyl tetrazolium chloride staining. Electrode-tissue contact is required for effective lesion formation during PFA. At the same PFA dose, lesion depth increases significantly with increasing CF.

Fontan Procedure: old lessons and new frontiers

The Fontan procedure is an operation created for patients with single ventricular physiology. These patients have the potential to survive well into adulthood, however new problems can arise. Various topics, including physiological constraints, patient care, morbidity and clinical outcomes are discussed. The aim of this review is to identify current topics within the care of the Fontan patient population for the physician not comfortable with their unique physiology and complications.

Infarct tissue characteristics of patients with versus without early revascularization for acute myocardial infarction: a contrast-enhancement cardiovascular magnetic resonance imaging study

Histopathological studies have suggested that early revascularization for acute myocardial infarction (MI) limits the size, transmural extent, and homogeneity of myocardial necrosis. However, the long-term effect of early revascularization on infarct tissue characteristics is largely unknown. Cardiovascular magnetic resonance (CMR) imaging with contrast enhancement (CE) allows non-invasive examination of infarct tissue characteristics and left ventricular (LV) dimensions and function in one examination. A total of 69 patients, referred for cardiac evaluation for various clinical reasons, were examined with CE-CMR >1 month (median 6, range 1-213) post-acute MI. We compared patients with (n = 33) versus without (n = 36) successful early revascularization for acute MI. Cine-CMR measurements included the LV end-diastolic and end-systolic volumes (ESV), LV ejection fraction (LVEF, %), and wall motion score index (WMSI). CE images were analyzed for core, peri, and total infarct size (%), and for the number of transmural segments. In our population, patients with successful early revascularization had better LVEFs (46 ± 16 vs. 34 ± 14%; P < 0.01), superior WMSIs (0.53, range 0.00-2.29 vs. 1.42, range 0.00-2.59; P < 0.01), and smaller ESVs (121 ± 70 vs. 166 ± 82; P = 0.02). However, there was no difference in core (9 ± 6 vs. 11 ± 6%), peri (9 ± 4 vs. 10 ± 4%), and total infarct size (18 ± 9 vs. 21 ± 9%; P > 0.05 for all comparisons); only transmural extent (P = 0.07) and infarct age (P = 0.06) tended to be larger in patients without early revascularization. CMR wall motion abnormalities are significantly better after revascularization; these differences are particularly marked later after infarction. The difference in scar size is more subtle and does not reach significance in this study.

Left ventricular free wall rupture associated with a combination of acute myocardial infarction and stress-provoked cardiomyopathy: An autopsy case

A 74-year-old female was admitted to our hospital due to prolonged chest pain that had lasted about 2 h. An electrocardiogram revealed ST-elevation in leads I, aVL, and V3-6, with an increase in myocardial necrosis markers. Emergency coronary angiography was performed, and left ventriculography showed the typical features of apical ballooning, and so a diagnosis of Takotsubo cardiomyopathy (TC) was made. On the 10th day after admission, the patient suddenly went into cardiopulmonary arrest because of a blow-out type left ventricular (LV) free wall rupture. Despite extensive cardiopulmonary resuscitation, the patient died. The autopsy revealed hemopericardium and a perforating wound located in the anterior wall of the LV. It was revealed that the diagonal branch of the coronary artery was occluded, and so a diagnosis of TC coexisting with acute myocardial infarction (AMI) was made. No previous case of TC accompanied by AMI has been reported. We present its clinical course during hospitalization and the result of a histopathologic examination.

[A clinicopathologic study of autopsy cases with myocardial infarction treated with coronary intervention (PTCA/Stenting)]

A clinicopathologic study was made in 28 patients who died after acute myocardial infarction (AMI) treated with coronary intervention (CI: Percutaneous transluminal coronary angioplasty (PTCA) or Stenting). Nineteen patients received PTCA (12 men and 7 women, 42 to 85 years of age, mean 71.4 years), and 9 patients received stenting after PTCA (8 men and 1 woman, 49 to 86 years of age, mean 67.7 years). Hemorrhagic infarction was found in 23 cases. Compared to direct PTCA, more severe hemorrhage was found in cases treated with PTCA after intracoronary thrombolytic therapy (rescue PTCA: r-PTCA). Also, severe hemorrhage in the infarct area was found in cases treated with percutaneous cardiopulmonary support (PCPS) after AMI. Hemorrhagic infarction was found even in patients treated with CI in the early phase after AMI, and also in some patients who recovered from initial heart failure after AMI. Compared to usual ischemic infarct, healing was greatly delayed in the hemorrhagic infarct area. We conclude that special care is required in the treatment of patients who received CI, because of a high possibility of hemorrhage in the infarct area after CI and the delay in healing in the hemorrhagic infarction area.

Histologic appearance of fractured thyroid cartilage and surrounding tissues

Histological appearances of the fractured superior horns (SH) of the thyroid cartilage and their surrounding tissues were reviewed, with particular reference to signs of vital origin of the fracture. Twenty-nine autopsies with either histories or findings indicating asphyxial neck compression, with a total of 39 fractured SHs, and three autopsies with history of suicidal jump from height with a total of two SH fractures, were examined. Fifteen autopsies with finding of 19 artefactually fractured SHs while removing neck organs at autopsy were used as controls. In the cases of neck compression and victims of jump from height haemorrhages, retraction of fractured SH fragments with invagination or squeezing of the perichondrium, contraction bands, contraction band necrosis and 'opaque fibres', in the adjacent muscle fibres could be seen. Fibrin deposition and/or leucocytic reaction were noted in cases where circumstances of death indicated prolonged death struggle (as in incomplete hanging, resuscitation or homicidal neck compression). However, retraction of fractured fragments and invagination of perichondrium between artefactually fractured SH fragments were observed in both control cases and cases with antemortem trauma to the larynx. Many of these histological findings, including haemorrhages and fractures had not been evident at gross examination. We conclude that histological examination of SHs may not only uncover macroscopically overlooked injuries but also may facilitate the clarification of an injury's vital origin.

[Arrhythmias in patients with congenital heart disease and their impact on prognosis]

Patients with congenital heart disease have an increased chance to suffer from brady- as well as tachyarrhythmias. The impact of these on quality of life, morbidity and mortality is more often imperative as compared to heart-healthy individuals. The substrate for these may be either congenital or acquired. Improvements of the surgical management of these patients have led, on the one hand, to improved survival rates with prolonged life expectancy within the last 2 decades, which on the other hand provided the basis for a higher rate of acquired cardiac arrhythmias. Together, this not only challenges diagnostics and therapy but also the prognostic relevance of these arrhythmias. The therapeutic strategies and prognostic markers have until now mostly been based on retrospective studies limited by the low number of patients and inhomogeneous patient selection. Despite these limitations, an increased risk of sudden cardiac death has been substantiated for certain patient groups, e.g., those operated on by the Mustard- or Senning procedures in patients with transposition of the great arteries and patients operated on with correction of the tetralogy of Fallot. However, until now it has not been possible to identify reliable markers for establishing the risk on an individual basis within these patient cohorts. For achieving reliable data on the symptomatic and prognostic effects of present-day--as well as new-coming--therapeutic strategies, it is mandatory to perform prospectively based, randomized multicenter studies. Furthermore, the well-appreciated synergism of hemodynamically and primarily of arrhythmia-based effects on prognosis could potentially be divided into their relative weight to better guide appropriate, substrate-related therapy. In addition, this should help to get better estimates of the risk for sudden cardiac death in different, etiologically homogeneous, groups of patients with congenital heart disease.

Histologic findings of transmyocardial laser channels after two hours

Histologic examination of the human myocardium has been performed several days, weeks, and months after transmyocardial laser revascularization. We performed microscopic examinations 2 hours postoperatively. In addition to the patent channel (diameter, 1 mm) and a 1-to 2-mm rim of necrosis, a 1- to 3-mm zone of myofibrillary degeneration was found. This additional reversible injury immediately after transmyocardial laser revascularization could explain the higher mortality rate in patients with reduced left ventricular function.

Transmyocardial laser revascularization (TMLR) in patients with unstable angina and low ejection fraction

OBJECTIVE

Does perioperative use of the intraaortic balloon pump (IABP) improve the postsurgical outcome of patients presenting with endstage coronary artery disease, unstable angina and low ejection fraction transferred for transmyocardial laser revascularization (TMLR)?

METHODS

TMLR, as sole therapy combined with the perioperative use of an intraaortic balloon pump has been assessed in seven patients with endstage coronary artery disease, unstable angina and low ejection fraction (EF < 35%). Six out of seven patients had signs of congestive heart failure. These patients are compared with 23 patients with endstage coronary artery disease, stable angina and EF > 35%, who were treated with TMLR as sole therapy without the use of IABP. The creation of transmural channels was performed by a CO2-laser. All patients were evaluated by hybrid positron emission tomography (perfusion SPECT and viability PET) and ventriculography preoperatively. Echocardiography, clinical status and hemodynamic assessment by Swan Ganz catheter were performed perioperatively.

RESULTS

The perioperative mortality of this combined procedure (TMLR and IABP) was zero. Three out of seven patients had pneumonia with complete recovery. Swan Ganz catheter examinations showed deterioration of LV-function after TMLR intraoperatively and improvement after 2 h and further after 6 h on ICU (P < 0.05). In contrast, a decrease of LV-function in sole TMLR patients with an EF > 35%) has not been observed. Patients with EF < 35% needed the IABP for 2.3 days and moderate dose catecholamines for a mean of 3.0 days. The postoperative EF and resting wall motion score index (WMSI) of all analysed LV segments (evaluated by echocardiography) did not change compared to baseline (EF 31.3+/-2.6 preop. to 32.8+/-3.2 postop.; WMSI: 1.75+/-0.14 at baseline to 1.71+/-0.17 postop.). The average Canadian Angina Class at the time of discharge decreased from 4.0+/-0 (baseline) to 2.3+/-0.5 (P < 0.05) and the NYHA-Index from 3.9+/-0.3 to 2.7+/-0.5. No patient had signs of angina pectoris, whereas two patients still had signs of congestive heart failure.

CONCLUSIONS

The reported data support our concept to start IABP preoperatively in patients with reduced LV contractile reserve in order to provide cardiac support during the postoperative phase of reversible decline of LV-function induced by TMLR.

Evaluation of agonal artifacts in the myocardium using a combination of histological stains and immunohistochemistry

The problem of discrimination between agonal artifacts and intravital ischemic myocardial lesions was studied with four histochemical stains [hematoxylin-eosin, Mallory's phosphotungstic acid hematoxylin (PTAH), modified luxol fast blue, and Lie's hematoxylin basic fuchsin picric acid (HBFP)] and with immunohistochemistry using two antibodies (antimyoglobin and anti-C5b-9). Seventy-five forensic autopsy cases were divided into six groups designed to represent successively shorter periods of agonal myocardial ischemia: (a) sudden deaths with coronary artery disease, macroscopically visible myocardial infarction, and/or fresh coronary thrombus; (b) unexplained sudden deaths without coronary artery disease; (c) accidental CO poisoning; (d) suicidal CO poisoning in cars; (e) suicidal hangings; and (f) instant traumatic deaths, i.e., total brainstem laceration or rupture of the thoracic aorta. From each heart, five pieces were removed from standardized locations, and six parallel sections were stained with each method (i.e., 30 sections from each heart). Hematoxylin-eosin and anti-C5b-9 were only positive in the first three groups, thus indicating specificity for intravital necrotic changes. The other staining methods were "positive" in one or more cases in all six groups, thus implicating a high degree of sensitivity for artifactual, agonal ischemic changes. The latter methods cannot be used alone in the diagnosis of myocardial infarction. By staining parallel sections with different stains and antibodies, it seems possible to estimate the relative length of the agonal period in cardiac and noncardiac deaths.

Early apoptosis in human myocardial infarcts

Myocardial apoptosis has previously been observed in human acute myocardial infarcts. We examined the time of appearance and extent of apoptosis in human acute myocardial infarcts, and compared these with necrotic cell death. Because nuclear internucleosomal DNA fragmentation is a hallmark of apoptosis, autopsied tissue from cases of acute myocardial infarct of varying histological ages was subjected to two tests that identify such fragmentation: in situ end-labeling (ISEL) and DNA electrophoresis on agarose gels. Both tests showed widespread apoptosis in infarcts only a few hours in age before the appearance of coagulative necrosis. No apoptosis was detected in normal myocardium. ISEL in recent infarcts was visible primarily in myocytes containing contraction bands, which occur predominantly in regions of reperfused myocardium. During the next 1 to 2 days, ISEL remained extensive but increasingly appeared in cells with morphological features of coagulative necrosis, representative of nonreperfused myocardium. In older infarcts, the incidence of apoptosis declined in myocytes, but increased in invading inflammatory cells. These data suggest that apoptosis is the early and predominant form of cell death in infarcted human myocardium, and that its appearance is accelerated in reperfused myocardium. Therapies directed at early rescue of apoptotic myocytes may, therefore, prove valuable.

Expression of bcl-2 protein, an inhibitor of apoptosis, and Bax, an accelerator of apoptosis, in ventricular myocytes of human hearts with myocardial infarction

BACKGROUND

In general, myocyte death in myocardial infarctions (MIs) is attributed to necrosis, but recently the involvement of apoptosis has been suggested. The ratio of bcl-2 protein, an inhibitor of apoptosis, to Bax protein, an inducer of apoptosis, determines survival or death after an apoptotic stimulus. We speculated that bcl-2 or Bax expression is induced by ischemia and that it may be related to myocyte death in human hearts.

METHODS AND RESULTS

We studied immunohistochemically 37 autopsied human hearts (acute MI, n = 15; old MI, n = 12; normal hearts as a control, n = 10) with the use of bcl-2 and Bax antibodies. There were no myocytes with positive bcl-2 immunoreactivity in the controls or hearts with old MI. However, myocytes with positive bcl-2 immunoreactivity were seen in 9 of 15 hearts (60%) with acute MI, in that it was localized only in salvaged areas surrounding the infarcted tissues. Myocytes with slightly positive Bax immunoreactivity were observed in the control hearts. In the salvaged myocytes surrounding the infarcted tissues, Bax was overexpressed in 2 of 15 hearts (13%) with acute MI but in 10 of 12 hearts (83%) with old MI.

CONCLUSIONS

bcl-2 protein is induced in salvaged myocytes at the acute stage of infarction, but Bax protein is overexpressed at the old stage. The expression of bcl-2 and the overexpression of Bax may play an important pathophysiological role in the protection or acceleration of the apoptosis of human myocytes after ischemia and/or reperfusion.

Myocardial indium-111 antimyosin uptake after uncomplicated coronary artery bypass surgery

The prevalence of myocardial damage after coronary artery bypass grafting is related to the criteria of its evaluation. Indium-111 monoclonal antimyosin antibody scintigraphy has been shown to be highly sensitive and specific for even small areas of myocardial necrosis or injury like those of myocarditis or transplant rejection. Our purpose was to evaluate, by using this method, myocardial damage after uncomplicated coronary artery bypass grafting. Uptake of this radio tracer was evaluated after coronary artery bypass grafting in 14 informed and consenting consecutive patients without previous myocardial infarction, with no post-surgical complications and a favorable postoperative course, following coronary artery bypass grafting for stable angina pectoris. Monoclonal antimyosin antibody indium-111 74 MBq (Myoscint Centocor) was injected on the third postoperative day; planar images in the anterior, left anterior oblique 45 degrees and 70 degrees projections were obtained 24 and 48 h later and analyzed for myocardial uptake. Indium-111 antimyosin uptake was present in 10 out of 14 patients (71.4%); it was diffuse in 6 and localized in 4. The ratio of the maximal counts in the myocardium to the counts in the adjacent lung background was measured and found elevated: 1.94 +/- 0.23, higher than the normal values reported in the literature. Indium-111 antimyosin uptake was clear in a group of patients after uncomplicated coronary artery bypass grafting. No correlation was observed between indium-111 antimyosin uptake or heart to lung ratio and creatine kinase, creatine kinase isoenzyme MB, glutamic oxalacetic transferase levels, duration of cardiopulmonary bypass or aortic cross-clamp time, while elevated serum beta myosin heavy chain fragments (IRMA Pasteur) were observed (1378 +/- 238 microU/l). This study suggests that some degree of myocardial damage, though silent, is common after coronary artery bypass grafting.

Necropsy study of the association between sudden cardiac death, cardiac isoenzymes and contraction band necrosis

AIMS

To assess whether a quantitative analysis of myocardial contraction bands could aid the postmortem identification of early myocardial infarction, especially if used in conjunction with cardiac isoenzyme activities.

METHODS

Sixty four coroner's necropsies were grouped by gross and histological findings into 26 cases of definite non-cardiac death, 12 cases of definite myocardial infarction and 26 cases in which there was occlusive coronary artery atheroma, but no demonstrable evidence of infarction. Using multiple sections of left ventricular myocardium stained with Heidenhain's iron haematoxylin, the number of myocardial cells containing contraction bands per unit area was quantified. The results were analysed statistically using logistic regression, and were then compared and combined with results from the statistical analysis of postmortem cardiac isoenzymes that had recently been undertaken on the same cases.

RESULTS

The number of cells containing contraction bands per unit area was higher in cases of definite myocardial infarction compared with those of non-cardiac deaths. In addition, cases of occlusive coronary artery atheroma only could be identified, indicating the presence of early myocardial infarction. The accuracy of this identification could be improved by combining these results with the results from the statistical analysis of postmortem cardiac isoenzymes.

CONCLUSION

The quantitative assessment of myocardial contraction band necrosis can provide useful additional information in cases of sudden death, where myocardial infarction is suspected but not identified on routine histological staining. The value of the information obtained is increased when used in conjunction with the postmortem measurement of cardiac isoenzyme activities.

Echocardiography in the management of single ventricle: fetal through adult life

Echocardiography contributes to the management of patients with single ventricle by providing an initial comprehensive evaluation in fetal and neonatal life. This allows planning of the initial surgical palliation, usually without the need for cardiac catheterization. Serial surveillance for problems such as subaortic stenosis, valvar insufficiency, or complications of the mitral palliation aids in planning for the timing and type of subsequent surgical procedures. Evaluation of single ventricle size, shape, and mass provides some indication of risk for a Fontan procedure. Transesophageal echocardiography provides an excellent window for the evaluation of the interatrial baffle for shunts, thrombi, or occlusion in the early postoperative period. Later, studies of ventricular and valve function help to direct medical management such as afterload reduction and diuretic therapy.

Hypertrophy of surviving myocytes overlying the infarct in human old myocardial infarctions with abnormal Q waves

The time course of hypertrophy of surviving myocytes overlying the infarct after the onset was examined and the hypertrophy was analyzed in relation to the transmural extent of infarct in 34 autopsied hearts with Q wave infarction. The 34 hearts were divided into 4 groups according to the length of time between the onset of infarction and death. This was less than 5 days in group 1 (n = 10), 20-30 days in group 2 (n = 7), 40-60 days in group 3 (n = 7), and 12-24 months in group 4 (n = 10). To clarify the regional hypertrophy of myocytes overlying the infarct, the size of the surviving myocytes in the outer third of the left ventricular wall in the 1-cm wide central zone of the infarct was compared with that of the myocytes in the outer third of the left ventricular wall without infarction (control wall) in the same heart. To exclude factors which stimulate the hypertrophy of the whole left ventricle, the ratio of the monocyte diameter in the infarcted wall to that in the control wall was examined. It was 1.0 +/- 0.0 (mean +/- SD) in group 1, 1.0 +/- 0.1 in group 2, 1.2 +/- 0.1 in group 3, and 1.3 +/- 0.1 in group 4. The ratio was significantly higher in group 3 than in group 1 and 2, and was highest in group 4. In group 4, the corrected percentage transmural extent of infarct indicating the original transmural extent of infarct at the acute stage was 63 + 8%, and this transmural extent correlated positively with the ratio of myocyte diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative estimation of infarct size by simultaneous dual radionuclide single photon emission computed tomography: comparison with peak serum creatine kinase activity

To test the hypothesis that simultaneous dual energy single photon emission computed tomography (SPECT) with technetium-99m (99mTc) pyrophosphate and thallium-201 (201TI) can provide an accurate estimate of the size of myocardial infarction and to assess the correlation between infarct size and peak serum creatine kinase activity, 165 patients with acute myocardial infarction underwent SPECT 3.2 +/- 1.3 (SD) days after the onset of acute myocardial infarction. In the present study, the difference in the intensity of 99mTc-pyrophosphate accumulation was assumed to be attributable to difference in the volume of infarcted myocardium, and the infarct volume was corrected by the ratio of the myocardial activity to the osseous activity to quantify the intensity of 99mTc-pyrophosphate accumulation. The correlation of measured infarct volume with peak serum creatine kinase activity was significant (r = 0.60, p less than 0.01). There was also a significant linear correlation between the corrected infarct volume and peak serum creatine kinase activity (r = 0.71, p less than 0.01). Subgroup analysis showed a high correlation between corrected volume and peak creatine kinase activity in patients with anterior infarctions (r = 0.75, p less than 0.01) but a poor correlation in patients with inferior or posterior infarctions (r = 0.50, p less than 0.01). In both the early reperfusion and the no reperfusion groups, a good correlation was found between corrected infarct volume and peak serum creatine kinase activity (r = 0.76 and r = 0.76, respectively; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Reperfusion injury in dog hearts with permanent occlusion of a coronary artery, probably due to reperfusion via collateral vessels

To clarify whether or not reperfusion injury occurs in the permanent occlusion of a coronary artery, we analyzed quantitatively contraction band necrosis as an indicator of early recanalization, coagulation necrosis, infarct size and measured regional blood flow in dog hearts with collateral circulation. Fifty mongrel dogs were divided into four groups: 15 dogs with a 24-hour occlusion of the left anterior descending coronary artery just distal to the first diagonal branch (permanent occlusion group): 15 dogs a with 3-hour occlusion followed by 24-hour recanalization (recanalization group); 10 dogs with a 2-hour occlusion without recanalization (transient occlusion group); 10 dogs with a 4-hour occlusion without recanalization (transient occlusion group). The regional blood flow in the subepicardium and subendocardium determined by the generated hydrogen gas clearance method was greatly decreased 30 minutes after occlusion (14 + 8%/12 +/- 9%) and was relatively restored from 180 minutes (31 +/- 21%/21 +/- 14%) to 24 hours later (41 + 19%/26 + 16%) in spite of complete occlusion of the coronary artery. The percentage infarct area in the risk area was significantly greater in the permanent occlusion group (60 +/- 26%) than in the recanalization group (35 +/- 31%). Although most of the infarct was occupied by contraction band necrosis in the recanalization group (86 +/- 12%), contraction band necrosis was diffusely seen even in the permanent occlusion group (54 +/- 27%). In both the permanent and recanalization groups, contraction band necrosis was the main histological feature of small infarcts occupying less than 30% of the risk area, while coagulation necrosis was the main feature in very large infarcts occupying more than 80% of the risk area. In the occlusion groups without recanalization, the percentage area of contraction band necrosis in the risk area was 6 +/- 8% after the 2-hour occlusion, 23 +/- 17% after the 4-hour occlusion and 31 +/- 21% after permanent occlusion; the difference between the 4-hour and permanent occlusion groups was not significant. In the permanent occlusion group, the percentage infarct area in the risk area was inversely correlated with regional blood flow during occlusion, an indicator of collateral flow. It was concluded that reperfusion injury occurs even in hearts without recanalization. The pathogenesis may involve reperfusion in the risk area via collateral circulation. Protection against reperfusion injury is important to minimize the infarct size even in hearts with permanent occlusion, although the presence of collateral flow is an important factor in limiting infarct size.

Cellular response of the evolving myocardial infarction after therapeutic coronary artery reperfusion

This study describes the cellular response of the evolving myocardial infarction in humans after early coronary artery reperfusion by one or more of the following therapies: streptokinase, percutaneous transluminal coronary angioplasty, tissue plasminogen activator, and/or coronary artery bypass graft surgery. Postmortem histologic changes were compared in two groups (n = 43 pairs) of human hearts with acute myocardial infarction matched for clinical age and left ventricular location of the infarct. The treatment group received one or more of the forms of reperfusion therapy. The control group received conventional therapy. The treatment group was judged to have an older histologic age infarct, P less than 0.002, compared with documented clinical age. For example, infarcts that were clinically 4 days old or less were judged histologically to be 1 day older. The treatment group had a higher Cellular Response Index, P less than 0.017; more hemorrhage within the infarct, P less than 0.001; a greater extent of selective myocardial cell necrosis, and a lesser extent of coagulation necrosis, P less than 0.05; more patchy, nontransmural distribution of necrosis, P less than 0.04; and a more florid cellular response, specifically more macrophages, P less than 0.034, and reactive stromal cells, P less than 0.05. In infarcts less than 3 days old clinically, the treatment group had hemorrhage and a cellular response which were wide-spread throughout the lesion, P less than 0.05, n = 18 pairs. In infarcts 3 to 4 days old clinically, the treatment group had a florid cellular response due to more macrophages, P less than 0.05, n = 9 pairs. In infarcts 5 to 10 days old, the treatment group had more macrophages, P less than 0.01; and more phagocytosis, P less than 0.003. In infarcts 10 to 40 days old clinically, the treatment group had scar formation that was patchy, P less than 0.05. In conclusion, this study demonstrates that early therapeutic coronary artery reperfusion after an acute myocardial infarction alters the pattern of injury and the cellular response to the evolving myocardial infarction so that the classical criteria for infarcts need to be modified.

Adjunctive use of beta-adrenergic blockers, calcium antagonists and other therapies in coronary thrombolysis

The availability of thrombolytic agents for use in the treatment of acute myocardial infarction is an important step in the management of a common, often debilitating, and potentially lethal disorder. However, despite the proven benefits of coronary thrombolysis, the importance of adjunctive treatment modalities is being increasingly recognized. Beta-adrenergic blockers, calcium antagonists, nitrates, magnesium, and angiotensin-converting enzyme inhibitors each exert favorable cardiovascular properties that may offer additional benefits. Clinical trials combining thrombolytic and adjunctive pharmacologic agents offer hope for further advances in the treatment of acute myocardial infarction.

Frequency of myocardial indium-111 antimyosin uptake after uncomplicated coronary artery bypass grafting

The reported incidence of myocardial damage after coronary artery bypass grafting (CABG) is highly related to the methods used. Since indium-111 monoclonal antimyosin antibody scintigraphy has been shown to be highly specific and sensitive for myocardial necrosis, even in small lesions, uptake of this radiotracer was evaluated after CABG. In 23 consecutive patients without previous myocardial infarction who underwent CABG for stable angina, 80 MBq indium-111 antimyosin was injected on the third postoperative day. Planar images were obtained 48 hours later and analyzed for myocardial uptake of indium-111 antimyosin. Scintigraphic results were related to creatine kinase MB levels, duration of both aortic cross-clamping and cardiopulmonary bypass, and electrocardiographic changes. In all patients surgical procedure and postoperative course was uncomplicated. Indium-111 antimyosin uptake was present in 19 of 23 patients (82%). It was diffused in 7 patients and localized in 12. No pathologic Q waves occurred postoperatively. Fourteen patients exhibited ST-segment changes. No good relation was found among indium-111 antimyosin uptake and creatine kinase MB levels, duration of cross-clamping or bypass, and ST-T changes. It is concluded that some degree of myocardial damage, though silent, is common after CABG.

Expression and distribution of atrial natriuretic polypeptide in the ventricles of children with myocarditis and/or myocardial infarction secondary to Kawasaki disease: immunohistochemical study

We studied the expression and distribution of atrial natriuretic polypeptide in the ventricles of 27 autopsied children with Kawasaki disease. Fourteen of the children had died in the acute stage of the disease. Three without any coronary artery aneurysms died due to myocarditis, while 11 with coronary artery aneurysms also had myocarditis but died of coronary heart disease. Histologic evidence of acute myocardial infarction was noted in three children who died of coronary heart disease. In the 14 children with acute-stage deaths, no abnormal expression of atrial natriuretic polypeptide was noted in the ventricles, despite the presence of heart failure in seven of them for 2 to 22 days before death. The other 13 patients had coronary artery aneurysms and died in the healed stage. In three patients with granulation tissue and congestive heart failure, myocytes in foci around the granulations were moderate to markedly positive for atrial natriuretic polypeptide. These three patients died over 8 days after the onset of their first myocardial infarct. Of 10 patients with old myocardial infarction, four had a history of congestive heart failure. They demonstrated moderate or marked atrial natriuretic polypeptide expression in extensive regions around sites of massive fibrosis, and foci of slight expression in the inner third of the noninfarcted region of the ventricle. In the other six patients without congestive heart failure, there was slight or moderate expression in foci around sites of massive fibrosis. We concluded that the expression of atrial natriuretic polypeptide appeared more than 1 week after the onset of acute myocardial infarction in the ventricles of children with Kawasaki disease who died in the healed stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac rupture, mortality and the timing of thrombolytic therapy: a meta-analysis

This study examined the relation between the risk of cardiac rupture and the timing of thrombolytic therapy for acute myocardial infarction. To test the hypothesis that cardiac rupture is prevented by early thrombolytic therapy but is promoted by late treatment, randomized controlled trials of thrombolytic agents for myocardial infarction were pooled. A logistic regression model including 58 cases of cardiac rupture among 1,638 patients from four trials showed that the odds ratio (treated/control) of cardiac rupture was directly correlated with time to treatment (p = 0.01); at 7 h, the odds ratio was 0.4 (95% confidence limits 0.17 to 0.93); at 11 h, it was 0.93 (0.53 to 1.60) and at 17 h, it was 3.21 (1.10 to 10.1). Analysis of data from the Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI) trial independently confirmed the relation between time to thrombolytic therapy and risk of cardiac rupture (p = 0.03). Analysis of 4,692 deaths in 44,346 patients demonstrated that the odds ratio of death was also directly correlated with time to treatment (p = 0.006); at 3 h, the odds ratio for death was 0.72 (0.67 to 0.77); at 14 h, it was 0.88 (0.77 to 1.00) and at 21 h, it was 1 (0.82 to 1.37). Thrombolytic therapy early after acute myocardial infarction improves survival and decreases the risk of cardiac rupture. Late administration of thrombolytic therapy also appears to improve survival but may increase the risk of cardiac rupture.

Clinicopathological study of myocardial infarction with normal or nearly normal extracardiac coronary arteries. Quantitative analysis of contraction band necrosis, coagulation necrosis, hemorrhage, and infarct size

In order to clarify the pathogenesis of acute myocardial infarction (MI) in hearts with normal coronary arteries, infarct size, and the extent of contraction band necrosis (CBN), coagulation necrosis, and hemorrhage were quantitatively examined using an image analyzer in 5 autopsy cases of MI with normal or nearly normal extracardiac coronary arteries. One patient died 40 h after acute MI. A second patient with acute MI due to severe spasm of segment 6, confirmed by cineangiography, died three days later. The third patient had already suffered a subarachnoid hemorrhage, and died 10 h after the onset of acute MI. The fourth patient had aortic stenosis and regurgitation. She developed acute MI due to total occlusion of segment 6, confirmed by cineangiography 4 h after the onset, and died 61 days later. Autopsy revealed old anteroseptal MI with normal coronary arteries and valvular thrombi. The fifth patient had a malignancy, and died one day after the onset of acute MI. Autopsy revealed multiple occlusive thrombi in the small intramural coronary arteries of the left ventricular wall supplied by segment 14, without any stenosis in the feeding vessel. Most infarcts were localized in the territory supplied by 1 or 2 of the 3 epicardial coronary arteries, and coincided with the clinically diagnosed infarct site. The infarct size ranged from 3%-26% of the left ventricular wall, and infarcts were generally localized to the inner third of the wall (67 +/- 20%). Histological examination of the four patients with acute MI revealed diffuse CBN (86 +/- 14% of the infarcted area) and/or hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Screening of myocardial contraction bands: a comparison between two histological staining methods

Two histological stains for demonstration of contraction bands (cb): Mallory's phosphotungstic acid hematoxylin (PTAH) and a modification of luxol fast blue (LFB) were compared. Microscopical sections from hearts from 60 autopsies were screened. The regional distribution of the cb lesions was also studied. It was found that PTAH showed cb more consistently than LFB. None of the stains were suitable for screening in the lowest magnification. In cases of cardiac death the cb were often extensive and scattered throughout the myocardium. In non-cardiac deaths with cb these were always discrete and seen only in one location which might be a means of differentiating lesions of pathogenetic importance from agonal ones.

Acceleration of cell necrosis following reperfusion after ischemia in the pig heart without collateral circulation

A study of whether reperfusion accelerates cell death was performed in 35 pig hearts without collateral circulation. In 15 animals, the distal one-third of the left anterior descending coronary artery was occluded for 1 hour followed by 1-, 3-, or 7-hour reperfusion in 5 animals each. As controls, 5 hearts each were examined after 1, 2, 4 and 8 hours of occlusion of the artery without reperfusion. Heart rate and aortic pressure before and during occlusion and reperfusion did not change in any group. The subepicardial and subendocardial regional blood flow decreased to almost zero in all hearts after occlusion (85 +/- 1 to 2 +/- 2) but recovered during reperfusion (65 +/- 15 ml/100 g/min). Specimens were histologically examined by an enzyme method using nitrotetrazolium blue, an immunohistochemical method using myoglobin antibody, by staining with hematoxylin-eosin and Masson's trichrome. In the control hearts, clear demarcation of the infarct area was observed 4 hours after occlusion. However, in the reperfusion group, clear demarcation of the infarct was seen after 1-hour reperfusion, namely, 2 hours after the onset of infarct. Demarcation was seen not only in the tissue with contraction band necrosis, but also in the tissue with coagulation necrosis. Therefore, it is concluded that reperfusion accelerates cell death due to both contraction band necrosis and coagulation necrosis.

Modified Fontan procedure: atrial baffle and systemic venous to pulmonary artery anastomotic techniques

Two technical modifications to the modified Fontan procedure are presented. Systemic venous to pulmonary artery continuity is achieved by superior vena cava (SVC) division and end to side anastomosis to the right pulmonary artery (RPA), particularly following a right Blalock shunt, or by RPA division and anastomosis to the SVC, particularly in the presence of RPA stenosis. Intra-atrial partitioning is achieved by a systemic venous baffle rather than a pulmonary venous baffle. This is particularly useful in the presence of left atrioventricular valve atresia, but may be a preferable technique with double-inlet single ventricle or single ventricle with common AV valve. These techniques were applied successfully to 10 of 12 children with various forms of single ventricle, including 5 with left AV valve atresia or stenosis.