Fragmented QRS complexes not typical of a bundle branch block: a marker of greater myocardial perfusion tomography abnormalities in coronary artery disease.

BACKGROUND: Fragmented QRS (FQRS) complexes, not typical of a bundle branch block, are a marker of regional myocardial injury. The extent of stress myocardial perfusion imaging (MPI) abnormalities with FQRS patterns is not known. METHODS AND RESULTS: Twelve-lead electrocardiograms (ECGs) in 501 patients undergoing stress MPI were studied. FQRS was defined as a QRS duration of 120 milliseconds or less, with notches or slurs of QRS complexes, on 2 contiguous leads of a coronary artery territory. Abnormal MPI was defined as a regional summed stress score (SSS) and summed rest score (SRS) of 3 or greater based on a 17-segment model. Patients with a typical bundle (n = 26), paced rhythm (n = 2), and Q waves (n = 64) were excluded. Of the remaining 409 patients (mean age, 58 +/- 13 years; 52% male), 155 (38%) had FQRS on the ECG. FQRS patients had a higher mean SSS, SRS, and global summed difference score and a lower left ventricular ejection fraction (all P < .001), as well as greater regional stress MPI scar (69% vs 11%, P < .001). FQRS pattern sensitivity was 75% and specificity was 94% for a corresponding regional MPI scar. On logistic regression, SSS, SRS, summed difference score, left ventricular ejection fraction, and regional scar were univariate predictors of the FQRS pattern on the ECG (all P < .01), and any regional scar (odds ratio, 32; P < .001) was a multivariate predictor. CONCLUSIONS: FQRS complexes on an ECG are a marker of higher stress MPI perfusion and functional abnormalities. Regional FQRS patterns denote the presence of a greater corresponding focal regional myocardial scar on stress MPI.

Electrocardiographic signs of remote myocardial infarction.

Twelve-lead electrocardiogram is an integral part of the evaluation of an acute and a remote myocardial infarction (MI). Electrocardiographic signs of an acute ST-elevation MI are more precise than those of an acute non-ST-elevation MI. Recognition of a remote MI is more difficult because once the repolarization abnormalities (ST-segment and T-wave changes) stabilize after an acute MI resolves, then the Q wave remains as the only universally recognized sign of MI. In addition, there is no specific sign of a non-Q-wave MI or a non-ST-elevation MI, or in fact of an ST-elevation MI that did not result in Q waves. The fragmented QRS (fQRS) is another recently described sign of a remote MI. It is defined by the presence of an additional R wave (R') or notching in the nadir of the S wave, or the presence of >1 R' (fragmentation) in 2 contiguous leads corresponding to a major coronary artery territory. The specificity of fQRS is inferior to that of a Q wave for an MI scar (89% vs 99%). However, fQRS has a superior sensitivity and a negative predictive value compared with a Q wave. In addition, there is an incremental gain in the sensitivity up to 91.4% when these 2 signs (fQRS and Q wave) are combined. The repolarization abnormalities of MI may also persist indefinitely as a sign of a remote MI in few patients. These abnormalities include persistent ST elevation, ST depression, nonspecific ST-T wave changes, and T-wave inversion.