[Cardiac rupture in acute myocardial infarct. Presentation of 20 postmortem cases]. / Ruptura cardiaca en el infarto agudo del miocardio. Presentación de 20 casos postmortem.

With the advancement of the Coronary Care Units in the past three decades, there had been an important reduction in mortality secondary to arrhythmias in acute myocardial infarction (AMI): been now days, cardiogenic shock and cardiac rupture the first and second causes of in-hospital death in these patients. The purpose of this report is to know the anatomoclinical characteristics in our hospital of cardiac rupture and to look for risk factors that may be considered to diagnose at the precise time this complication that might cause sudden death secondary to hemodynamic and electromechanical changes. From 300 postmortem cases with AMI proved clinical, and by anatomopathological studies, 20 cases with cardiac rupture were obtained, among which: 11 (55%) were males with an average age of 61.7 years and 9 (45%) females, with an average age of 60 years. The following coronary risk factors were detected: systemic hypertension in 15 (75%) cases; cigarette smoking in 13 (65%) cases and diabetes mellitus in 11 (55%) cases. Long lasting or recurrent history of chest pain previous to death was present in 14 (70%) cases. Conduction disturbances were detected in 13 (65%) cases; among them, 7 (35%) had third degree heart block in whom permanent pacemaker was inserted; 4 (20%) had CRBBB and 2 (10%) ASB. The average heart weight was 478 gr. in males and 434 gr. in females. Evidence of an old MI was present in 7 (35%) cases. All patients had transmural MI. Free cardiac wall rupture was seen in 14 (70%) cases and from the ventricular septum, 6 (30%) cases. Hemopericardium was present in all cases (100%) with an average amount of 425 ml of blood. Pericarditis in 3 (15%). The average time of evolution since the beginning of the AMI until death were 4 days and the main causes of death were cardiogenic shock in 17 (85%) and congestive heart failure in 3 (15%).

The effects of ajmaline in experimental and clinical arrhythmias and their relation to some electrophysiological parameters of the heart.

The antiarrhythmic efficacy of ajmaline has been evaluated in three experimental models of cardiac arrhythmias in the dog. These data have been related to the actions of the compound on several parameters of heart function and compared to results obtained in various clinical arrhythmias. Ajmaline was more effective in arrhythmias of the ectopic focus type than in the circus movement model. These results agreed with the pattern of clinical activity. The compound produced decreases in excitability and conduction and increased the functional refractory period in all heart tissues. These effects were most marked in the atrium. The drug also showed a moderate degree of anticholinergic activity. Both in the dogs and in the clinical cases, the agent showed an important hypotensive effect. In a group of experiments in which transmembrane potentials were recorded, the compound produced in all tissues a decrease in upstroke velocity and amplitude of the action potential; it also increased the duration of the action potential in atrial and ventricular muscle, but it decreased it in Purkinje fibers. The possible mechanism(s) of action of the drug is discussed in terms of the different hypotheses for cardiac arrhythmias.