Safety and feasibility of two-dimensional echocardiography and myocardial perfusion imaging in patients with chest pain.

The accurate identification of patients at high risk for acute coronary syndromes among those seen in the emergency department with possible myocardial ischemia and nonischernic electrocardiograms is a problem. Two-dimensional echocardiography and myocardial perfusion imaging with 99m-technetium sestamibi can identify patients at low and high risk; however, comparative studies are lacking. The authors studied 555 patients considered at low or moderate risk for myocardial ischemia in our emergency department on the basis of the presenting history, and results of physical examination and electrocardiography. These patients underwent echocardiography and myocardial perfusion imaging within 4 hours of presentation. Endpoints included myocardial infarction, percutaneous transluminal coronary angioplasty, and positive results on stress perfusion imaging. Both imaging procedures were performed in the emergency department on 370 patients. Overall agreement between the two techniques was high (concordance, 89%) in the patients who had myocardial infarction or underwent coronary angiography. Agreement between the two techniques is high when used in patients with possible myocardial ischemia. Both techniques helped identify patients at high risk who required admission and those who could be safely discharged.

A study of sentinel node biopsy in T1 breast cancer treatment: experience of 48 cases.

Axillary clearance in breast cancer has been proven to be unnecessary in more than 50% of cases. Sentinel node biopsy (SNB) is a new technique that can be used to avoid unnecessary axillary clearance in breast cancer surgery. Our integrated team, consisting of surgeons, pathologists and nuclear medicine physicians, studied 48 cases of T1 breast cancer with lymphoscintigraphy-guided SNB. Before starting this study, the team performed 20 SNBs as a learning procedure. 500 microCi of 99mTc-nanocoll in 0.2 mL were injected around the lesion, under US or x-ray guidance if necessary. Static images in anterior, lateral and lateral oblique view collected at the end of a 20 min dynamic study were used to mark the SN on the skin. During surgery a gamma probe was used to guide SN resection, and node invasion was assessed with cytokeratin immunohistochemistry. In 14 patients tracer uptake was observed in a single node, in 30 patients in 2-4 nodes, whereas in four patients the nodes were scintigraphically missed. Surgical resection was possible in 42 nodes out of 54. All but two patients with negative immunohistochemistry for cancer cell clusters showed metastasis-free axillary nodes. All patients with positive SNBs (13) showed involved axilla. In four patients the lymphatic drainage was towards the intramammary chain; one node was juxtaclavicular and one node was intramammary in the upper outer quadrant. The overall sensitivity of the method was about 80%, the specificity about 90% with a diagnostic accuracy about 80%. SNB is a promising method for surgical decision-making regarding axillary clearance in breast cancer. Adequate training of an interdisciplinary team is needed in order to successfully perform SNB and assess SN invasion. Its unusual anatomic location can be encountered and technical care is necessary to correctly identify and remove them.

[Planar myocardial scintigraphy with 99mTc sestamibi for the evaluation of the infarct area and the efficacy of the thrombolytic therapy]. / Scintigrafia miocardica planare con tecnezio-99m-sestamibi per la valutazione dell'estensione dell'area infartuale e dell'efficacia della terapia trombolitica.

BACKGROUND: Nuclear cardiology permits the estimation of myocardial infarction size and the result of the thrombolytic therapy. The aim of the study was to demonstrate the feasibility of the planar myocardial scintigraphy with tecnetium-99m-sestamibi in the coronary intensive care unit for the early identification of the infarct size and the results of the thrombolytic therapy. MATERIAL AND METHODS: We studied 15 patients affected by a first acute myocardial infarction (AMI), 10 anterior and 5 inferior wall, treated with thrombolysis (APSAC 30U i.v.) within and interval of 3 hours from the symptoms onset, tecnetium-99m-sestamibi was injected before thrombolysis and after 3 +/- 1 hours the planar imaging was registered with a mobile gamma-camera. Scintigraphic evaluation was repeated after 24 hours and before patient discharge. Within 48 hours from the thrombolytic therapy the coronary angiography was performed for the demonstration of patency of the infarct-related artery. The left ventricle myocardial perfusion was divided in the 3 planar projections into 13 segments. The perfusion in each segment was evaluated with a perfusion score: 0 = normal, 1 = moderately reduced, 2 = severely reduced, 3 = absent. The sum of the hypoperfused segments represented the infarct size. A perfusion score improvement greater than 40% was considered a marker of reperfusion. RESULTS: The infarct size involved 4.2 +/- 1.5 segments in the anterior and 2 +/- 0.8 segments in the inferior wall infarctions (p < 0.05). The scintigraphic imaging made 24 hours after AMI allowed the diagnosis of coronary reperfusion in 10 patients. The coronarography demonstrated the infarct related artery patency in 14 patients. The nuclear imaging at patient discharge provided the diagnosis or reperfusion in 11 cases and demonstrated an improvement of the myocardial perfusion score in 8 cases. CONCLUSIONS: In patients with AMI treated with thrombolysis the scintigraphic imaging with tecnetium-99m-sestamibi is feasible with a mobile gamma-camera in the intensive coronary care unit. The quality of planar imaging is good and allows the evaluation of myocardial infarct size and the efficiency of thrombolytic therapy. An earlier scintigraphic imaging should be taken into consideration for a more timely non-invasive evaluation of patients who need coronary angiography and, if necessary, a rescue-PTCA.

QT dispersion and early arrhythmic risk during acute myocardial infarction.

It has been suggested that QT dispersion (maximal minus minimal QT interval calculated on a standard 12-lead electrocardiogram) could reflect regional variations of ventricular repolarization and could provide a substrate for reentry ventricular arrhythmias. The present study evaluates QT dispersion in patients with acute myocardial infarction, assessing its relation with early severe ventricular arrhythmias and some clinical features. Three hundred three patients with acute myocardial infarction and a control group of 297 healthy subjects were studied. QT and QTc dispersion were determined on the electrocardiogram taken after 12 hours and on days 3 and 10 after symptoms onset and on the electrocardiogram taken in the control group. The average values of QT and QTc dispersions (ms) were as follows: 70.5 +/- 42.5-87 +/- 45.6 (12th hour), 66.7 +/- 37.6-76.8 +/- 43.6 (day 3), 68.8 +/- 42.7-76.8 +/- 42.8 (day 10), versus 43 +/- 13.2-53.9 +/- 16.2 (control group). There were statistically significant differences between QT and QTc dispersion recorded in normal subjects and in each of the three electrocardiograms taken in patients with infarction. A greater QT dispersion was recorded in patients with anterior infarction (78.9 +/- 38.5 vs 64.9 +/- 42.8 in inferior/lateral infarction). In the first 3 days QT dispersion was not different in patients treated and untreated with thrombolysis, whereas on day 10 it was greater in untreated patients (74.9 +/- 45.3 vs 60.5 +/- 37.2). Creatine kinase peak level did not influence QT dispersion. In the first 72 hours of infarction, 37 patients developed ventricular fibrillation or sustained ventricular tachycardia. Higher early values of QT and QTc dispersion were found in patients who developed severe ventricular arrhythmias (107.8 +/- 62 and 124.8 +/- 67.5 ms) than in patients without serious arrhythmias (62.9 +/- 32.2 and 80.1 +/- 37.9 ms). These data suggest that: (1) QT dispersion increased during acute myocardial infarction. (2) The values were higher in the early hours and fell late after infarction with thrombolysis. (3) Greater QT dispersion is associated with severe ventricular arrhythmias.

[Correlations between the efficacy of thrombolytic therapy and appearance of abnormal Q waves in the early stages of acute myocardial infarction]. / Correlazione tra efficacia della terapia trombolitica e comparsa di onde Q patologiche nella fase precoce dell'infarto miocardico acuto.

BACKGROUND: The purpose of this study was to determine the time course of the appearance of abnormal Q waves on the electrocardiogram (ECG) over the first 6 hrs of the symptoms of acute myocardial infarction (AMI) and to determine what implications, if any, such Q waves have for the efficacy of thrombolytic therapy. Severe myocardial ischemia can produce early QRS changes in the absence of infarction. Abnormal Q waves on the baseline ECG may not be an accurate marker or irreversibly injured myocardium. METHODS: A study of 232 patients with AMI consecutively admitted to our coronary care units was carried out. Patients with previous AMI were not included. The presence and number of abnormal Q waves, as defined by Selvester, on the initial ECG was determined for each patient. The presence or absence and magnitude of ST segment elevation and depression were recorded and these data were used to estimate the left ventricular infarct size should thrombolytic therapy not be given (Aldrich score). Quantitative thallium-201 tomographic imaging was performed after a mean of 42 +/- 40 days from hospital discharge in 145 patients. RESULTS: In patients admitted within 1 hr of symptoms, 53% had abnormal Q waves on the initial ECG independent of the duration of symptoms before therapy (p < 0.001). Despite this finding, the presence of abnormal Q waves on the admission ECG did not eliminate the effect of thrombolytic therapy on reducing final infarct size (p < 0.001). CONCLUSIONS: Abnormal Q waves are a common finding early in the course of AMI. However, there is no evidence that abnormal Q waves are associated with less benefit in terms of reduction of infarct size after thrombolytic therapy.