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Biomedical subjects

L C Romero-Ayala

Publications and source records attributed to L C Romero-Ayala.

7 recordsLinked to original sources

Evidence for a class 4 effect of cibenzoline "in vivo".

In anesthetized dogs, it has already been shown that cibenzoline (4 mg/kg i.v.) possesses class 1 anti-arrhythmic properties. In this work, the cardiac electrophysiologic effects of cibenzoline (1 mg/kg i.v.) were studied before and after propranolol (0.2 mg/kg i.v.) treatment. Cibenzoline caused a slight tachycardia, a reduction of conduction velocity in the His-Purkinje system and in the ventricle, but no significant effects in the atria and the atrioventricular node were detected. On the contrary, when dogs were given the beta-adrenoceptor blocking agent propranolol, cibenzoline produced major effects in the slow response structures, especially in the sinus node and the atrioventricular node (bradycardia and depression of the atrioventricular nodal conduction). No further effects were observed on the His-Purkinje system and ventricle as compared to administration of cibenzoline alone. In dogs, cibenzoline given i.v., had no effects on the slow response systems, probably because of sympathetic nervous system intervention since the class 4 effects of cibenzoline appeared after beta-adrenoceptor blockade.

Anesthesia↗

[Cardiac involvement in ankylosing spondylitis].

Ankylosing spondylitis is a rheumatic disease that affects the axial skeleton and has predilection for young men. Of its extraarticular manifestations, the cardiac involvement, reported up to 48%, has been pointed out in recent years. It seems to exist a racial variation in the features of the spondylitis and since most of the studies have been performed in northern countries therefore it appears inadequate to extrapolate the conclusions of such studies to our society. We studied 23 patients with definitive diagnosis of ankylosing spondylitis. All of them had a complete physical examination, electrocardiography and X-ray of the chest; eight patients underwent a Holter study of 24 hours and seven patients were examined by echocardiography. The mean age of the group was 36 years; there were 21 men and two women. The mean duration of the rheumatic disease was 11.5 years. In only 4 (17.4%) of the patients we found cardiac involvement that would not be related to another etiology. By the clinic examination we found two patients with isolated aortic insufficiency; one case had a right bundle branch block. The Holter study did not show modifications, except in the one with isolated aortic insufficiency and right bundle branch block, in whom this block became of variable degree. The echocardiographic study showed the mentioned aortic valvular lesions and did reveal the same lesion in another patient in which the other studies were normal. It is emphasized that it is adequate to search for signs of ankylosing spondylitis in every patient with isolated aortic insufficiency or/and conduction disturbances of unknown etiology and also to performe cardiac careful in each patient with ankylosing spondylitis examination.

Aortic Valve Insufficiency↗

[New anti-arrhythmia drugs].

In this paper some of the new antiarrhythmic drugs are reviewed. The origin, electrophysiologic effects, mechanisms of action, pharmacokinetic properties, hemodynamic changes, clinical utilization with indications and contraindications as well as the collateral effects of: Verapamil Amiodarone, Aprindine, Encainide, Mexiletine and Tocainide are analyzed. A conclusion is drawn for each one of these drugs in accordance with the available information in the literature and the author's criteria and experience.

Amiodarone↗

[Fibrous fixed subaortic stenosis].

Fifty eight patients with isolated with discrete subaortic stenosis or in association with just another heart defect, were studied between 1961 and 1980. The age range was between 2 and 42 years. The evaluation of each case was done according to clinical manifestations, systolic overloading of the left ventricle and the amount of the systolic gradient. There is a poor correlation between the clinical, electrocardiographic and hemodynamic parameters according to the student t test in the preoperative evaluation. Forty-one patients were operated, two of them died in the early post-operative period. There was a good clinical evolution with significant values comparing pre and post-operative symptoms. The decrease in the systolic gradient in 26 cases after surgery was significative (p less than or equal to 0.005). Based on the natural history of this malformation and on the results obtained with the surgical treatment, we may conclude that there is surgical indication once the diagnosis is made, because this malformation has a completely different evolution compared with other forms of congenital aortic stenosis.

Adolescent↗

[Effect of intravenous disopyramide in supraventricular paroxysmal tachycardia refractory to vagal maneuvers].

The objective of this study was to prove the efficacy of intravenous disopyramide in the treatment of paroxysmal supraventricular tachycardia resistant to vagal maneuvers. Nine patients with this condition were admitted to the emergency service of the Instituto Nacional de Cardiología Ignacio Chávez. They were given an intravenous bolus of 2 mg/kg of the drug a maintenance dose of 0.4 mg/kg during 3 hours. The undesirable effects of the drug were arterial hypotension, dizziness, dry mouth, transient A-V dissociation and scape-capture rhythm. In conclussion, disopyramide is an excellent drug in the treatment of paroxysmal supra-ventricular tachycardia resistant to vagal maneuvers, but an strict monitorization of the arterial pressure and electrocardiogram should be kept during its administration.

Adult↗