Relationship of QRS duration at baseline and changes over 60 min after fibrinolysis to 30-day mortality with different locations of ST elevation myocardial infarction: results from the Hirulog and Early Reperfusion or Occlusion-2 trial.
OBJECTIVE
To discern if the prognostic meaning of QRS prolongation differs according to the location of ST elevation acute myocardial infarction


METHODS
Measuring QRS duration in patients with normal conduction or right bundle branch block


METHODS
HERO-2 trial with prospective collection of electrocardiograms at randomisation and at 60 min after fibrinolytic therapy


METHODS
12 456 patients with normal conduction at both randomisation and 60-min time points and 510 with right bundle branch block (RBBB) at both time points


METHODS
30-day mortality.


RESULTS
On the baseline ECG, there was a positive association between QRS duration and 30-day mortality with anterior acute myocardial infarction (AMI) (p<0.0001 for those with normal conduction and = 0.007 for those with RBBB) but not with inferior AMI (p = 0.29 and p = 0.32, respectively). For anterior AMI, with or without RBBB, an increment of 20 ms increase in QRS duration predicted a significant 30-40% relative increase in 30-day mortality both before and after adjusting for clinical and ECG variables including baseline ST elevation and presence of Q waves. The association was not present for inferior AMI. Changes in QRS duration over 60 min after fibrinolytic therapy were uncommon and unrelated to mortality.


CONCLUSIONS
Baseline QRS duration independently stratifies 30-day mortality in patients with anterior AMI, even when unaccompanied by RBBB, but does not stratify mortality risk in patients with inferior AMI.
Wong
C-K
CK
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland 1030, New Zealand. harveyw@adhb.govt.nz
Gao
W
W
Stewart
R A H
RA
French
J K
JK
Aylward
P E G
PE
White
H D
HD
D000368:Aged; D002037:Bundle-Branch Block / Q000188:drug therapy / Q000503:physiopathology; D002986:Clinical Trials as Topic; D003627:Data Interpretation, Statistical; D004562:Electrocardiography; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology*; D011379:Prognosis; D012044:Regression Analysis; D018570:Risk Assessment; D015912:Thrombolytic Therapy; D016896:Treatment Outcome
D005343:Fibrinolytic Agents