Aims: To determine the incidence of different morphological type of myocardial laceration (wall rupture) in patients who died of acute myocardial infarction, as well as to study the several clinical forms of presentation of different types of myocardial laceration. CONCEPT OF THE STUDY: To apply a protocol of prospective study, that includes 64 clinical and 34 anatomical parameters, using very discriminative technics in the anatomical study, already presented in previous papers. PLACE OF THE STUDY: The study took place in a CCU and pathological department of a University Hospital.
Population: Of 1308 patients successively admitted in a CCU with acute myocardial infarction between 1983-1986, 252 have died. It was possible to perform a necropsy study in 193. The only criterion for inclusion was the family agreement.
Methods: The study was a prospective one, being excluded only the patients in whom the anatomical study didn't confirm recent myocardial infarction. The clinical data were observed during the stay in the CCU, using a protocol developed for this study. In the anatomical study a protocol developed by the authors was applied, using very discriminative anatomical quantification technics of the infarct size as well as of the coronary obstruction degree by atherosclerotic plaques. In the study of the myocardial laceration a fourteen septal perpendicular cuts technic was applied, with a laceration development macroscopic study, and microscopic study of the more interesting cuts. All data were stored and treated in a computer program developed for this study.
Results: From the 193 cases that have been studied, 49 presented a complete free wall rupture (25%) and in two others there were an interventricular septal rupture and free wall rupture. The amount of free wall rupture was then 51 cases (26%), with a corrected incidence for the population with AMI of 5.1%. In 7 cases we found an interventricular septal rupture (in two cases associated with complete free wall rupture and in other two cases with an incomplete left ventricular rupture), what represents an incidence in necropsy of 3.6%. Since that in this period five patients with septal rupture have been operated and in three others the hemodynamic diagnosis was made, dying this patients without being performed necropsic study, the amount of septal ruptures was of 15 cases, what represents a corrected incidence of 1.1% in the population with AMI. The clinical forms of presentation of free wall rupture were the following: syncope followed by death (60%), shock (21%), transitory syncope (4%), psycho-motor troubling (4%). Pain persistence or recurrence associated with other clinical symptoms occurred in 63% of the patients. Hypotension, not always evoluting to shock, occurred in 33%, and pericarditis in 21% of the cases. When the different anatomical types of free wall rupture were considered (type I-direct rupture; type II-multicanalicular rupture; type III-rupture covered by an interventricular thrombus), we observed that in type I there was prevalence of syncope (71% and only 50% showed pain persistence or recurrence, when in type II syncope occurred in 67% and shock in 22%, with pain in 56%, and in type III the occurrence of syncope and shock were similar (44% vs 38%), with pain in 81% of the cases. Hypotension was verified in 56% in type III, 21% in type I and 22% in type II. Pericarditis never occurred in type I, happened in 33% in type II and 25% in type III. The terminal accident took an average 44 minutes long in type I, 3.8 hours in type II and 9.2 hours in type III. The delay in admission was nine hours in type I, 19 in type II and 30 in type III, and the time between the onset of symptoms and death was 2.9, 2.7 and 5.4 days respectively in types I, II and III. In what concerns the interventricular septal rupture shock occurred in all cases but one, in which association with free wall rupture determined cardiac tamponade with syncope.(ABSTRACT TRUNCATED AT 400 WORDS)