RESUMEN
BACKGROUND: Nuclear cardiology permits the estimation of the 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 Technetium-99-m-sestamibi in the coronary intensive care unit for the early identification of the infarct size and the result of the thrombolytic therapy. MATERIALS AND METHODS: We considered 10 patients affected by a first myocardial infarction (5 anterior and 5 inferior wall) then treated with thrombolytic therapy (APSAC 30 U. iv) within an interval of 3 hours from the onset of the symptoms. Technetium-99-m-sestamibi was injected before the thrombolytic therapy and the planar imaging was registered after 2-3 hours with a mobile gamma-camera. After 24 hours and before patient discharge we repeated the scintigraphic evaluation. Within 24 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 perfusion, 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 4.4 +/- 1.4 segments in the anterior and 2 +/- 0.6 segments in the inferior wall infarctions (p < 0.05). The scintigraphic imaging made 24 hours after the myocardial infarction allowed the diagnosis of coronary reperfusion in 7 patients. The coronary angiography demonstrated the infarct related artery patency in 9 patients (all with TIMI perfusion score = 3). The nuclear imaging at patient discharge provided the diagnosis or reperfusion in 8 cases and demonstrated an improvement of the myocardial perfusion score in 5 cases. CONCLUSION: The scintigraphic imaging with Technetium-99-m-sestamibi in the patients with a myocardial infarction treated with thrombolytic therapy 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 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.
Asunto(s)
Corazón/diagnóstico por imagen , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/tratamiento farmacológico , Tecnecio Tc 99m Sestamibi , Terapia Trombolítica , Anciano , Anistreplasa/administración & dosificación , Pruebas Enzimáticas Clínicas , Angiografía Coronaria , Electrocardiografía , Estudios de Factibilidad , Femenino , Fibrinolíticos/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Cintigrafía , Factores de TiempoRESUMEN
Nine patients, 7 males, 2 females, mean age 36 years, with myotonic muscular dystrophy who had no cardiac symptoms underwent M-mode echocardiography (e.), systolic time intervals (STI) measurement by simultaneous recordings of the electrocardiogram, phonocardiogram and carotid arterial pulse, and single-pass radionuclide angiocardiography (RNA) in order to assess the left ventricular function. The ejecting phase indexes measured by echocardiography (fractional shortening, mean velocity of circumferential fiber shortening) were slightly depressed in 1 case and an abnormal PEP/LVET ratio was found in 3 cases. The ejection fraction measured by radionuclide angiocardiography was abnormal in 1 case who showed a diffuse hypokinesia. The IVI%, a new isovolumic phase index obtained by echocardiography, was abnormal in all patients. It is concluded that the IVI% seems more sensitive than the ejecting phase indexes calculated by echocardiography or radionuclide angiocardiography and the PEP/LVET ratio in detecting abnormalities of left ventricular function in patients with myotonic muscular dystrophy and no clinical signs of heart disease.
Asunto(s)
Gasto Cardíaco , Distrofias Musculares/fisiopatología , Contracción Miocárdica , Volumen Sistólico , Adolescente , Adulto , Angiocardiografía , Ecocardiografía , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Frequency and importance of secondary pauses (SP) following termination of high rate artrial pacing were evaluated in 64 patients. The maximal values of the first 10 post-pacing cycles, resulting from series of pacing between 70/min--160/min, were compared with the normal post-pacing values of Benditt. SP were present in 1 case (4%) of 23 patients without electrocardiographic signs of sinus node dysfunction (SDF), but in 21 cases (51%) of 41 patients with SDF (p less than 0.01). SP were more frequent in patients with SA-Block and/or sinus pauses (64%) and with bradycardia-tachycardia-syndrome (60%), whereas were more rare (35%) in patients with sinus bradycardia only. Patients with SDF and SP did not significantly differ from patients with SDF without SP concerning absolute and corrected sinus node recovery time, basal heart rate, reduction of cycle length after atropine, abnormal reactions to carotid sinus pressure and frequency of syncopes. In 1 patient SP, present in basal conditions, were not evident after atropine. SP could be interpreted as indication of SDF and should always be searched for because it may be the only evidence of SDF after atrial pacing; therefore SP may reduce the frequency of false negative tests after rapid atrial pacing. Possibly, vagal mechanisms are involved.