Insulin impairs the anticonvulsive activity of carbamazepine against maximal electroshock-induced seizures in mice.

In view of the data indicating that insulin can modify penetration of some drugs across cell membranes and tissue barriers, particularly the blood-brain barrier, the aim of the present study was to evaluate the effect of insulin on both the anticonvulsant activity and the brain concentration of carbamazepine in mice suffering from seizures induced by maximal electroshock. The antiepileptic drug was administered per os in single doses either alone or in combination with insulin given as single intraperitoneal injections. To assess the anticonvulsant activity of carbamazepine the ED50 values were calculated. The results indicate that insulin given in doses up to 2 units/kg did not affect the convulsive threshold, whereas insulin applied at 2 units/kg led to a significant reduction in the anticonvulsant activity of carbamazepine, as judged by an increase in the ED50 value from 16.2 to 41.3 mg/kg. This effect was accompanied by the marked reduction in both the brain and blood concentrations of the drug. It is likely, therefore, that the inhibitory activity of insulin on the anticonvulsive function of carbamazepine is related not only to the effect of the former on the blood-brain transport of the latter, but also to insulin-induced modulation of the serum concentration of the drug.

[Tendinous cords in echocardiographic studies--occurrence, clinical significance]. / Struny sciegniste w badaniu echokardiograficznym--wystepowanie, znaczenie kliniczne.

Tendinous chords inside cardiac ventricles were found in 53 (5.6%) out of 954 individuals examined echocardiographically within one year. Only 30 individuals were further analysed. No marked pathology in the cardiovascular system was found. Tendinous chord was localized in the right ventricle in 7 individuals, in left ventricle in 21, and in both ventricles in 2 subjects. Ventricular arrhythmias were shown in 11 subjects (36.6%) with the aid of a 24-hour ECG monitoring with Holter's technique. They were of the II and IV stage of advancement according to Lown's classification. Ventricular rhythm disorders were seen in both subjects with tendinous chord within left ventricle (7 subjects) and in the right ventricle (4 subjects). Local diastolic disorders with no effect on the ejection fraction were noted in all subjects with false chord and ventricular rhythm disorders. Ventricular cardiac rhythm disorders are being observed in the subjects with the false chord located within the right or the left cardiac ventricle producing local diastole disturbances.

[Treatment of supraventricular paroxysmal tachycardia and auricular flutter by auricular stimulation]. / Tratamiento de la taquicardia paroxistica supraventricular y del flutter auricular con estimulación auricular

Although the management of supraventricular tachycardias (SVT) and atrial flutter (AF1) with drugs or cardioversion is usually effective, their use in the high risk patient commonly digitalized, may be dangerous. Since the availability of an alternate therapeutic method is desirable, the usefulness of atrial pacing was evaluated in 31 episodes of tachyarrhythmia in 31 patients with varied heart conditions. The arrhythmia diagnosis and the stimulation were done through a right atrial electrode. In most cases the rate of stimulation was higher than that of the atria (up to 400 stimuli per min). Of 17 cases with SVT (four with preexcitation syndrome), pacing led to sinus rhythm (SR) in all, even though it was transient in two. SR was obtained in six of eleven cases of AF1, through a short lasting atrial fibrillation (AF) in three of them. Four patients with paroxysmal atrial tachycardia with A-V block changed to AF. SR was achieved shortly after termination of the procedure in two of the latter. It is concluded that atrial pacing is a valuable therapeutic method since it is effective, it has very low risk specially in digitalized patients, its does not require anesthesia and because it may be used repeatedly in case of recurrence. The technique of atrial pacing permits, in some cases, the identification of the mechanism responsible for the arrhythmia.

[Hemodynamic evaluation in acute myocardial infarct. Application to the treatment of contractile insufficiency syndromes of the left ventricle]. / Valoración hemodinámica en el infarto agudo del miocardio. Aplicaión al tratamiento de los sindromes de insuficiencia contractil del ventriculo izquierdo

Even though the coronary care units have reduced to a minimum the mortality due to arrhythmias, the syndromes of left ventricular failure are responsible for the greatest part of hospital deaths in patients with acute myocardial infarction. The poor results depend upon the extensive destruction of left ventricular mass. The management in these cases should be directed to improve the performance of viable muscle as well as to preserve thejeopardized ischemic myocardium that is potentially viable. These goals may be adequately pursued by continuous hemodynamic characterization of left ventricular function. The experience of the Coronary Care Unit of the Instituto Nacional de Cardiología de México in the study of 30 of these patients is presented. Hemodynamic evaluations were performed by means of a Swan-Ganz catheter and cardiac output determinations by the thermodilution technique. The studies may be performed with a minimum of risk. Central venous pressure measurements do not adequately indicate the status of the left ventricle. Its function may be evaluated by the use of end diastolic pulmonary artery pressure which reflects, quite accurately, the left ventricular filling pressure in these patients. Continuous hemodynamic monitorization facilitates the proper manipulation of the determinants of ventricular performance (preload, afterload, cardiac rate and contractility) and permits an attempt to improve the balance between available oxygen and myocardial oxygen requirements. Hemodynamic studies and ventricular function curves are presented in selected patients with acute myocardial infarction. The mortality due to left ventricular failure and cardiogenic shock in patients with acute myocardial infarction remains extremely high. However, it is only through the early recognition by continuous hemodynamic monitorization and the aggressive management of the patient with incipient left ventricular failure that the number of survivors may be increased.

[The bradycardia-tachycardia syndrome]. / El sindrome de bradicardia-taquicardia

Disorders of the heart rhythm which consist basically of sinus bradicardia or sinus arrest correspond to a syndrome which has been named the sick sinus syndrome. Within the framework of this syndrome, there is a subgroup of alternating atrial bradycardia with episodes of atrial tachyarrhythmia. Generally known as the bradycardia-tachycardia syndrome, this subgroup is both electrophysiologically interesting and therapeutically challenging. This report is concerned with the experience obtained at the emergency ward and coronary care unit of the Instituto Nacional de Cardiología de México on the diagnosis and management of 8 patients with this syndrome. Various underlying heart conditions were present with predominance of ischemic heart disease. The clinical picture was dependent upon the hypoperfusion of vital organs secondary to the cardial arrhythmia. The most common symptoms were derived from cerebral circulatory deficit and coronary insufficiency. Half of the patients had moderate cardiac failure. All patients had spontaneous and transient loss of sinus function which lasted more than 2,000 msec. in seven. The bradycardia had a rate below 50 beats per minute in all cases except one. The tachyarrhythmias observed were atrial flutter, atrial fibrillation and paroxysmal supraventricular tachycardia. Three of the patients had more than one of these these tachyarrhythmias during the period of study. A discussion is made on the diagnosis of this syndrome by means of atrial pacing and interventions which modify either vagal or sympathetic tone. Considerations are also made on the frequent associated abnormality of the A-V functional tissues. Emphasis is placed on the problems encountered in the management of these patients. It is concluded that, in most cases, a satisfactory result may be obtained by the implantation of a permanent demand pacemaker associated to the administration of antiarrhythmic drugs.