Aspectos eléctricos de la asociación de miocardio inactivable y bloqueos tronculares de grado intermedio / Electrical manifestations of dead myocardium associated to proximal blocks of intermediate degree

The electrical manifestation of dead myocardium associated to incomplete bundle branch block, i.e., with a limited [quot ]jumping wave[quot ] phenomenon, are exposed. Our description is based on previous experimental studies and validated by electro-anatomical comparisons. In previous experimental reports, the electrical manifestations of dead myocardium in the presence of varying degrees of associated block have also been described. The main electrocardiographic changes are related to the location and extent of damaged region and to degree of bundle branch block. If a left bundle branch block coexists with dead myocardium, small Q waves are registered in left unipolar leads exploring the damaged area. In these leads, the signs of subepicardial or transmural injury are increased. When a right proximal block coexists, the main changes concern the morphologies registered in the unipolar right epicardial and precordial leads. The electrical changes are due to the spatial orientation of the electromotive forces of ventricular depolarization and repolarization. The electrocardiographic changes described here can be satisfactorily understood in the light of the present knowledge on the ventricular electrical phenomenon.

Manifestaciones eléctricas de alteraciones miocárdicas asociadas a preexcitación ventricular / On the electrical manifestations of some heart diseases associated with ventricular preexcitation

Electro-Vectorcardiographic curves, corresponding some heart diseases, must be analyzed in the light of the ventricular depolarization sequence, as well as on the heart's position and rotation. A more than 30-msec interval between the end of the initial slurring (delta) and the vertex of the R wave in the left unipolar leads or the main axis of the vectorcardiographic ventricular curves, allows us to infer the coexistence of left ventricular hypertrophy. On the other hand, segmental irregularities or distorsions of the electric curves suggest the presence of a limited myocardial zone unable to be activated. Extensive or multiple deformations of these curves are more suggestive of a diffuse myocardial damage. Sometimes signs of preexcitation, due to a pharmacological action, can also appear.

Apoyo metabólico del corazón isquémico en cirugía cardíaca / Metabolic support of the ischemic heart during cardiac surgery

We examine [IBM1] the basic principles and clinical results of the metabolic intervention with glucose-insulin-potassium (GIK) solutions in the field of cardiovascular surgery. On the basis of many international publications concerning this subject, and the experience obtained in the operating room of the Instituto Nacional de Cardiologia [quot ]Ignacio Chávez[quot ], we conclude that the metabolic support wit GIK is a powerful system that provides very useful energy to protect the myocardium during cardiac and non-cardiac surgery. The most recent publications indicate their effects in reducing low output syndromes, due to interventions on the coronary arteries, as well as producing a significant reduction of circulating fatty acids. These effects are produced also in the field of interventional cardiology, where GIK solutions protect the myocardium against damage due to impaired microcirculation. It is evident that these solutions must be utilized in higher concentrations that the initial ones, equal to those employed in laboratory animals. On the other side, it is worthy to remember that it has been always underlined that this treatment represents only a protection for the myocardium. Therefore, its association with other drugs or treatments favoring a good myocardial performance is not contraindicated--on the contrary, it yields better results. The present review presents pharmacological approaches, such as the use of glutamato, aspartate, piruvato, trimetazidina ranolazine and taurine to optimize cardiac energy metabolism, for the management of ischemic heart disease.

Un enfoque epistemológico en la esfigmomanometría / Epistemological focus on sphygmomanometry

In the XVIII century, the English naturalist Stephen Hales started to apply blood sphygmomanometry in animals. Direct recording of the blood pressure was first applied, in the XIX century, by AE Chauveau and JLM Poiseuille. However, it was not until 1856 that it was possible to perform a direct determination of blood pressure in humans by means of a device designed by Faivre. The first sphygmomanometer appeared at the end of the XIX century. The physician Samuel K. von Basch, native of Prague and who lived a few years in Mexico, fabricated successively three models of sphygmomanometers. The first (1881), with a mercury column, proved to be the most practical and useful. This instrument inspired the sphygmomanometer of the Italian physician Scipione Riva-Rocci who presented it in 1896. His sphygmomanometer, supported on the Vierordt principle, could measure manometrically the force needed to stop the pulse wave. Thanks to the research of Russian physician N. Korotkoff, the auscultatory method was added to sphygmomanometry. During the XX century other instruments to measure blood pressure were fabricated: the Pachon's and Plesch's oscillometers, as well as the aneroid manometer. On the other side, the use of direct tensional recordings has subsisted which has allowed to document the wide oscillations of arterial pressure levels during the day. Anyway, the sphygmomanometer with a mercury column has persisted until the present and will still be used for a long time. A new evolving methodology is the continuous ambulatory sphygmomanometry.