An assessment of wall motion, perfusion and glucose metabolism in recent myocardial infarction: a comparison in patients with and without revascularization

The aim of this study was to compare the extent and severity of wall motion abnormalities, perfusion and glucose metabolism, in recent myocardial infarction in patients with and without revascularization. Forty-nine patients were studied (82% men; mean age 58 years) by using echocardiography, 201Tl single photon emission computed tomography (SPECT) rest and redistribution, and 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) SPECT at a mean of 9.2 days (range, 1-24 days) after myocardial infarction. Twenty-seven of the 49 patients underwent revascularization while the other 22 received medical therapy before echocardiography and studies using radionuclides. A contrast angiogram was obtained for each patient. A follow-up echocardiogram at 3 months was obtained for 44 patients. Images were read blindly, using a 17 segment model, with semi-quantitative analysis. In the whole group, the extent of hypokinesia was 15%+/-14 (mean+/-SD); the extent of mild defects was determined as 5%+/-6 by using 201Tl at rest, 6%+/-9 by using 201Tl redistribution, and 4%+/-6 by using 18F-FDG (P<0.0005, echocardiogram/radionuclides). Echocardiography showed that the extent of akinesia-dyskinesia was 16%+/-18 in revascularized patients and 28%+/-18 in non-revascularized patients (P=0.017). With regard to moderate and severe defects, 201Tl rest showed 19%+/-16 and 28%+/-17, respectively (P=0.047); 201Tl redistribution 17%+/-15 and 26%+/-15, respectively (P=0.043); and 18F-FDG 17%+/-13 and 24%+/-15, respectively (NS). In echocardiography, the extent of hypokinetic segments decreased from 16%+/-15 at baseline to 10%+/-11 at 3 months (P=0.045), in revascularized patients. It is concluded that, in recent myocardial infarction, hypokinesia extent on echocardiogram is greater than mild perfusion or metabolic defect extent, reflecting stunning and so the use of radionuclide techniques appear more accurate for defining the extent of myocardial infarction. Non-revascularized patients showed a significantly greater extent of akinesia-dyskinesia and moderate-severe perfusion defects than did revascularized patients, which can be considered a result of therapy. It is suggested that 201Tl rest perfusion be used for the assessment of myocardial infarction soon after revascularization.

[SPECT tomography with F 18-fluorodeoxyglucose in a recent myocardial infarction clinical case]

We report a 50-year-old woman with a recent myocardial infarction in whom a myocardial perfusion single photon emission computed tomography (SPECT) with Thallium201 was done simultaneously with a F18-fluorodeoxyglucose (FDG) SPECT to study glucose metabolism. Myocardial infarction was located in the anteroseptal and apical regions and an echocardiography, done at the second day of evolution, showed a septo-apical hypokinesia. On the tenth day, a coronary angiography showed a critical lesion of the anterior descending coronary artery and an angioplasty with stent placement was performed on the next day. On the twelfth day, a resting, redistribution 201Tl SPECT to study viability and a FDG-SPECT with a dual head high-energy collimator camera were done. Images, acquired 45 min after injection, were analyzed visually. In anterior and medial apical sectors, discordance between flux and metabolism, considered a classical mismatch, was observed. Echocardiographic hypokinesia disappeared three month after revascularization.

[Intravenous tissue plasminogen activator in the treatment of acute ischemic stroke: feasibility, safety, and efficiency in the 2 first years of the clinical practice]

BACKGROUND

The only effective therapy for the treatment of acute ischemic stroke is the infusion of tissue plasminogen activator in the first three hours after the onset of symptoms.

AIM

To report the experience with tissue plasminogen activator infusion in the treatment of acute ischemic stroke.

PATIENTS AND METHODS

Ten males and 10 females, aged 52 to 85 years old with an acute ischemic stroke, admitted within 89 min after the onset of symptoms were studied. Tissue plasminogen activator was infused following the guidelines designed by the National Institute of Neurological Disorders and Stroke (NINDS). Patients were assessed according to Rankin scale after three months of follow up.

RESULTS

All patients had normal CAT scans. The delay between the onset of symptoms and the infusion ranged from 75 to 180 min. One patient had a gastrointestinal bleeding due to a gastric ulcer and one patient had a fatal intracranial hemorrhage. After three months of follow up, 38% of patients had a good recuperation (Rankin 0 to 1), 33% had a mild to moderate disability (Rankin 2 or 3) and 14% had a moderate to severe disability (Rankin 4). There was a 15% mortality.

CONCLUSIONS

This series show that treatment of acute ischemic stroke with tissue plasminogen activator is feasible and safe. The obtained results are similar to those reported abroad.

Simultaneous assessment of function and perfusion during dipyridamole-handgrip Tc-99m sestamibi imaging in chronic coronary artery disease

The main goal of this work was to know the value of ventricular function in addition to perfusion Tc-99m sestamibi images in the assessment of coronary artery disease (CAD) when using dipyridamole (DIP) associated to isometric exercise. We analyzed 52 patients with suspected CAD; 40 of them had coronary lesions > or = 50% and 12 patients without CAD, conforming study and control groups, respectively. Twenty-eight patients had prior myocardial infarction. A two-day sestamibi protocol was employed with i.v. DIP-handgrip and rest injections, acquiring ECG-gated first pass and planar perfusion images. Sensitivity for perfusion images was 85% and specificity was 91.7%. There was no change between rest and DIP ejection fraction (EF) in controls. CAD patients presented a significant EF decrease with DIP (p: 0.0015). Patients with ischemia in perfusion images had larger EF decrease (p: 0.0001). For the analysis, an EF drop > or = 5% and any wall motion abnormality (WMA) were considered as having an abnormal response to DIP. CAD sensitivity improved significantly to 92.5% when adding EF drop and to 90% when adding WMA parameters, but specificity decreased to 75% with EF drop, and to 58.3% with WMA. In conclusion, first pass parameters from DIP-isometric exercise in addition to perfusion images are not a significant help in the assessment of CAD.

[Primary coronary angioplasty as a choice treatment in the 1st 6 hours following acute myocardial infarction]

Primary coronary angioplasty as treatment of acute myocardial infarction preserves more myocardium and has a lower mortality than thrombolysis. Aiming to assess the feasibility of its use in Chile, we studied 64 patients aged 59 +/- 2 years old, 27 with an anterior wall and 37 with an infero-lateral wall acute myocardial infarction of 118 +/- 62 min of evolution. Coronary angiography, performed 98 +/- 47 min after diagnosis, showed non significant disease in one, one vessel disease in 26 (40%), two vessel disease in 17 (27%) and three vessel disease in 20 (31%) patients. Responsible arteries for infarction were the anterior descending in 26 (40%), circumflex in 9 (14%), right in 27 (42%), a saphenous bridge in one and left main disease in one patient. In one patient with an obstruction over 50% and in two patients with left main disease, angioplasty was not attempted. The procedure was successful (defined as a residual lesion of less than 50%) in 56 of 61 patients (92%) and failed in four. One patient was re-perfused with intracoronary streptokinase. The delay in reperfusion was lower during working than non-working hours (89 +/- 48 vs 113 +/- 39 min). Four patients (6%) died during hospitalization, two had a reinfarction, two had a new vessel occlusion and three had a spontaneous ischemia. Eleven patients were operated during hospitalization and in two this was an emergency procedure. After 1993, mortality was lower (one of 55 patients) than before (three of nine). It is concluded that early coronary angioplasty in acute myocardial infarction is feasible in Chile, with a high degree of success.

[Mechanical reperfusion in acute myocardial infarction after failure of thrombolysis with intravenous streptokinase]

AIM

to report the clinical evolution of four patients with acute myocardial infarction that were subjected to immediate coronary angioplasty due to the failure of reperfusion with streptokinase.

BACKGROUND

the limitations for the use of thrombolytic agents, an accepted treatment of acute myocardial infarction, or their uncertain results in selected groups of patients has prompted the search for mechanical revascularization infarction subjected to thrombolytic therapy with streptokinase (1.500.000 U i.v.) after administration of hydrocortisone (100 mg i.v.) and acetyl salicylic acid (500 mg od). After 60 min thrombolytic therapy and due to hemodynamic depression with requirement of inotropic agents or the absence of clinical signs of reperfusion, the patients were subjected to coronary angiography. In view of a total occlusion or severe stenosis of the artery responsible for the infarction, an immediate transluminal angiography was performed to improve coronary flow.

RESULTS

transluminal coronary angioplasty revascularized arteries with total occlusion or increased the lumen of those with severe residual stenosis. This was accompanied by reduction in pain and hemodynamic improvement. In one patient with complete AV block, conduction was improved and sinus rhythm was recovered. Echocardiographic controls showed preservation of ventricular function with persistence of segmental motility alterations.

CONCLUSIONS

transluminal coronary angioplasty can be a revascularization alternative in patients with acute myocardial infarction and failure of reperfusion with systemic streptokinase.

[Angiographic findings in non-Q wave infarction and their relation to ST-T changes]

Non q wave myocardial infarction has been attributed to occlusion of a vessel with no ECG representation, early reperfusion of the occluded artery or occlusion of a vessel with generous collateral flow. The coronary arteriography of 84 patients with non Q wave myocardial infarction performed at 16 + 17 (SD) days after infarction was analyzed. Main left lesion was found in 6 (17%), single vessel disease in 30 (36%), two vessel disease in 18 (24%) and 3 vessel disease in 16 (19%). The "culprit" vessel had a critical residual lesion in 38 patients (45%): 22 affected the left anterior descending artery, 10 the circumflex, and 5 the right coronary artery. No residual lesion was found in 10 patients (12%). An occluded artery was found in 32 patients (38%): circumflex in 20, right coronary artery in 9 and left anterior descending in 3 (p < 0.01). Significant collateral flow to the occluded vessel was present in 41% of cases. The ST segment was analyzed in 82 patients. Depression of ST was found in 29 (35%), elevation in 22 (27%), negative T waves in 17 (21%) and minimal alterations in 17%. There was no correlation between ST levels and coronary occlusion of the culprit artery. Depression of ST was more commonly (p < 0.01) associated with severe coronary artery disease (main left or 3 vessel disease), which may be related to the poorer prognosis in these cases.

[Myocardial ischemia in patients older than 70 years of age. Clinical and angiographic aspects]

We studied 77 patients with clinical suspicion of ischemic heart disease whose age ranged from 70 to 84 years. Patients with atypical angina had mostly normal coronary arteries, while those with unstable angina usually had three vessel disease or main left disease. According to the left ventricular function, surgery was considered safe in 66% of patients with unstable angina and 33% of those with stable angina. One patient developed a pseudoaneurysm at the arterial puncture site and hematomas were present in 3 other patients. Currently we try to avoid coronary arteriography in older patients with atypical angina due to its low yield.

[Massive pulmonary thromboembolism treated with selective infusion of streptokinase. Report of 2 cases]

We report 2 patients who developed massive pulmonary embolism with greater than 50% occlusion of the pulmonary arterial circulation. Hypotension, syncope and right sided failure were the clinical manifestations. Immediately after diagnostic pulmonary arteriography, 20,000 U of streptokinase (SK) were delivered in the pulmonary artery next to the thrombotic mass. A continuous infusion of SK, 10,000 U/h was maintained for 24 h in one patient and 72 h in the other. Rapid clinical improvement was observed in the following 24 h. Control angiography showed lysis of the embolus with residual obstructions of segmentary branches. The clinical value of this form of treatment for pulmonary embolism is discussed.

[Quantification of mitral valve area: usefulness of Doppler]

We studied 34 patients with mitral stenosis by means of doppler echocardiography. Several patients had non significant associated valve lesions. The mitral valve area was measured by planimetry of the mitral orifice as recorded in the short axis view and also using the Hatle formula as applied to pulsed doppler recordings of transmitral flow velocity. The correlation between both measurements was excellent (r = 0.92). Direct measurements of mitral valve area obtained at the time of operation showed no significant differences from those estimated by echocardiography in 15 surgically treated patients.

Superior vena cava syndrome: a complication of transvenous pacemaker implantation

Superior vena cava syndrome developed in 4 of 1,000 patients in whom a transvenous pacemaker had been implanted. In all cases, endocardial leads were inserted through the cephalic vein and positioned at the apex of the right ventricle. The classical signs and symptoms of superior vena cava hypertension were observed from two weeks to one year after implantation, and the diagnosis was confirmed by cavography. Symptoms resolved following heparin therapy and long-term anticoagulation.

Parapharyngeal rhabdomyoma

Rhabdomyoma is a benign tumor of striated muscle origin that is very rare in young children. Review of the world literature revealed 20 cases of extracardiac adult-type rhabdomyoma in the head and neck area. All reported cases have been encapsulated and easily excised. A 22 1/2-month-old girl with a parapharyngeal rhabdomyoma is unique in that her tumor had atypical histology and lacked a capsule; it could not be "shelled-out".

Fish bone fistulae

This is a communication of a fish bone in the cervical esophagus of an adult causing a common carotid false aneurysm with fistula to the esophagus (not reported previously).

The effect of harmaline on force of contraction of the rat isolated atrium

In rat isolated right atria, beating spontaneously at 30 degrees C, harmaline 8.3 times 10-5 M slowed atrial rate and enhanced force of contraction. The velocity of development of tension (dT/dt) increased and time to peak tension was lengthened. Electrical drive of otherwise quiescent left atria showed that (1) within the range of change of rate induced by harmaline the reduction of frequency of stimulation increased dT/dt and peak tension developed, and (2) at a constant rate of stimulation harmaline produced a prolongation of time to peak tension and an enhancement of peak tension. We concluded that two mechanisms are responsible for the inotropic action of harmaline on rat atrium: (1) an increase in dT/dt due to the lengthening of the interval between beats; (2) a direct action of harmaline on the processes responsible for atrial contraction, which determines a lengthening of time to peak tension.