Ischemic blocks during early phase of anterior myocardial infarction: correlation with ST-segment shift.
Of 760 consecutive cases with anterior acute myocardial infarction (AMI), 55 developed acute bundle-branch block (BBB), fascicular block, or high-degree atrioventricular block during the hyperacute ECG stage of AMI. According to the direction of the ST segment during the acute ischemic episode, patients were divided into two groups. Group A consisted of 32 patients who developed BBB during ST-segment elevation, positive T wave, and absent or minimal Q wave. Group B consisted of 23 patients who developed BBB during ST-segment depression and evolved into anterior AMI. Group A was characterized by a higher incidence of right BBB and left anterior hemiblock [91% vs. 26% and 56% vs. 13%, respectively (p less than 0.005)]. Group B was characterized by a higher incidence of left BBB and left posterior hemiblock [57% vs. 9% and 26% vs. 12%, respectively (p less than 0.001)]. The BBB was transient (disappearing within hours to one day) in 14 patients in Group A and in 5 patients in Group B. The incidence of progression to high-degree atrioventricular block was almost equal in the two groups (25% and 26%). The mortality rate was very high in both groups, but higher in Group B [74% vs. 59% (p = NS)] especially in those with LBBB (85%). Most patients died on the day of occurrence of BBB [Group A, 50% vs. Group B, 70% (p = NS)]. The causes of death in both groups were cardiogenic shock and/or electromechanical dissociation.(ABSTRACT TRUNCATED AT 250 WORDS)
Sclarovsky
S
S
Israel and Ione Massada Center for Heart Diseases, Beilinson Medical Center, Petah Tikva, Israel.
Sagie
A
A
Strasberg
B
B
Shnapick
Y
Y
Rechavia
E
E
Kusniec
J
J
Agmon
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000145:classification / Q000401:mortality / Q000503:physiopathology*; D003326:Coronary Circulation; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000401:mortality / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D012189:Retrospective Studies