Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome (ACS). Consequently, its presentation and optimal treatment are yet to be clearly defined. In the current literature, all case series report less than 50 patients, most of whom are either young peripartum women or women who have used oral contraceptives over long periods. All information in this study was compiled by the database service from two hospitals, the first one between 2003 and 2012 and the second one between 2007 and 2012, to include the clinical characteristics, angiography. and treatment approaches in the study population. The study population consisted in four women (50%) and four men (50%) whose ages ranged between 28 and 57 years. Two women had a history of oral contraceptive use and three women presented during peripartum. None of the patients had traditional cardiovascular risk factors or previous heart disease. In 88% of the cases, the principal diagnoses were non-ST segment elevation myocardial infarction and unstable angina. All patients underwent emergency coronary angiography and percutaneous coronary intervention. Half of them were treated with drug-eluting stents and the other half with bare metal stents. The most frequent type of dissection was NIHBL Type E, and the right coronary artery was the most frequently compromised. SCAD is a rare cause of ACS; however, its identification has improved due to the availability of angiography and new complementary techniques. Regarding treatment, PCI seems effective with adequate long-term results.
A method of producing focal ventricular block is described. The sequence of the electrocardiographic variations is ascribed to changes in the velocity and direction of the excitatory process in the ventricular wall. The epicardial electrocardiograms resemble those considered indicative of ventricular hypertrophy or of "incomplete" or of "complete" bundle branch block. When the focal block is pronounced a positive deflection appears in the cavitary tracing. The ventricular blocks can be subdivided into "conduction blocks" and "fiber blocks," the former produced by the delay of the stimulus in the specialized conduction system and the latter produced by the delay of the excitatory process in the ordinary heart muscle. polarizable electrode, and the left arm terminal was connected to the exploring electrode through a similar nonpolarizable boot.2 A rather large, olive shaped, electrode of German silver was introduced in the ventricular cavities, the indifferent electrode was attached to the left hind leg. Direct leads were taken upon the epicardial surface of the ventricular muscle supplied by the artery in which the injection was given. Control electrocardiograms were always taken; during the experiments tracings were obtained from distant ventricular zones, and occasionally curves were recorded while the exploring electrode was moved slowly over the epicardial surface. Cavitary leads were obtained where the more illustrative electrocardiographic changes were observed; curves were also taken while the electrode was moved in the ventricular cavity. Direct-writing electrocardiographs were found to be useful in locating the most convenient points for obtaining permanent records. IN RESULTSThe saline solution of cocaine when injected in a coronary artery caused a "parietal focal block" (p.f.b.) in the ventricular territory irrigated by the vessel. The focal block developed rapidly while the injection was being given, and disappeared gradually in 15 to 30 minutes. The electrocardiograms taken while the exploring electrode was moved slowly over the epicardial surface demonstrated that the ventricular region where the parietal focal block was maximal was encircled by zones in which the degree of the block gradually decreased ( fig. 1). The blocked ventricular zone was found
M ANY different abnormalities of the QRS complexes have been described, and a large number of these are easily recognized and have been shown to have a more or. less precise significance. On the other hand, the different abnormalities of the T complex that have come to be widely recognized as distinctive and as having a definite connotation are few. Abnormalities in the direction of the T wave have received a great deal of attention and several different varieties of inverted T waves are distinguished. Abnormalities of the size of upright T waves have also been described, although these are recognized with greater difficulty than abnormalities in the direction, and their meaning is less clearly understood. Comparatively little has been done toward the analysis of abnormalities of the shape of upright T waves, although it is known, for example, that potassium retention in some cases of uremia may give rise to a tall, pointed T wave of more or less distinctive outline.'v2 The purpose of this article is to call attention to certain types of upright T waves which differ in shape from normal T waves and become inverted under a variety of circumstances, alike in certain particulars. MATERIAL AND METHODS We have examined 100 normal electrocardiograms collected by Bryant." The ages of the subjects studied by him ranged from 19 years to 32 years. He recorded the standard and unipolar limb leads and precordial Leads VZ and Vd. W'e have taken in Lima and in Ann Arbor 100 additional electrocardiograms on normal subjects 20 to 75 years of age. This series includes seven precordial leads (VI, VZ, VB, V.,, Vs, Vs, and Vs), as well as the six limb leads. In 80 of these 100 cases the effect of carotid sinus massage was investigated. In forty instances, all of the thirteen leads mentioned were taken before, and at least Leads I, II, Vn, VF, Vs, V4, Vs, and Vs were taken during this procedure. In the remaining forty cases it was studied in a smaller number of leads. The age of the subjects upon which this test was performed ranged from 20 to 75 years, with an average age of 37 years. The effect of carotid sinus massage upon the form of the T wave
Las modificaciones de las ondas r precoces en las derivaciones precordiales derechas cuando sobreviene un bloqueo izquierdo se deben al curso anormal de la excitación en el tabique. La manera como progresa la onda de activación en las regiones comprometidas por el bloqueo y la anormal orientación de los vectores que representan las fuerzas eléctricas de esas regiones, pueden explicar las modificaciones de QRS-T que se observan en los electrocardiogramas al sobrevenir el bloqueo izquierdo. El análisis de los cambios correlativos de las "ondas B" u ondas de bloqueo y de las ondas que representan la activación ventricular normal aclara- la patogenia de los bloqueos izquierdos. Los bloqueos izquierdos electrocardiográficamente se manifiestan como "intraparietales". Los diferentes tipos de bloqueo izquierdo se deben al grado y magnitud del deterioro funcional de las fibras musculares especializadas en las cuales la activación progresa muy velozmente. Por su extensión los bloqueos izquierdos son "parciales" o "totales". La duración del complejo ventricular no define si un bloqueo izquierdo es "completo" o "incompleto". En una determinada derivación la forma del electrocardiograma puede indicar si un bloqueo izquierdo es "completo" o "incompleto". Un bloqueo izquierdo es "incompleto" en la zona explorada cuando "ondas B" coexisten con deflexiones que pueden representar la activación normal de músculo ventricular izquierdo. Un bloqueo izquierdo es "completo" en la zona explorada cuando solo existen "ondas B" y no hay ninguna evidencia de inflexiones que representan la activación normal. En el texto se discuten las dificultades y las limitaciones que existen para el diagnóstico electrocardiográfico de la hipertrofia ventricular izquierda.
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