Abstract 15666: Terminal T-Wave Concordance Increases the Sensitivity of Electrocardiographic Diagnosis of Acute Myocardial Infarction in Left Bundle Branch Block
Introduction: We have previously shown that the first two Sgarbossa criteria modified with the Smith ratio rule (concordant ST elevation (STE) >= 1 mm; concordant ST depression (STD) >= 1 mm in V1-V3; or ST/S ratio =< -0.25) can diagnose acute coronary occlusion (ACO) with 90% sensitivity and specificity. But these modified Sgarbossa criteria are likely less sensitive for the diagnosis of MI without ACO (NSTEMI). In Sgarbossa’s original study, T-wave concordance in V5 or V6 was specific but insensitive for any MI (STEMI or NSTEMI); we previously reported that this is also true for STEMI patients.
Hypothesis: We hypothesize that T-wave concordance will be a sensitive and specific marker of NSTEMI in LBBB.
Methods: Retrospectively, ECGs of ED patients with LBBB and ischemic symptoms were obtained. STEMI patients had 1) angiographically proven complete ACO or 2) culprit lesion and troponin I >= 10 ng/ml. NSTEMI patients were those in which ACO was excluded but had clinically diagnosed MI. Control patients had negative troponins. Measurements were ST segment at the J-point and S-wave amplitude. The T-wave was concordant if the majority of the T-wave was in the same direction as the majority of the QRS complex. Terminal T-wave concordance was defined as a biphasic T-wave with the terminal portion > 0.5 mm in the direction of the QRS. Statistics were by McNemar’s test.
Results: The STEMI, NSTEMI, and no-MI groups consisted of 33, 24, and 105 patients. Both terminal T-wave concordance and overall T-wave concordance were more sensitive but less specific than the original Sgarbossa criteria for diagnosis of NSTEMI (Table 1; p < 0.05). Addition of terminal T-wave concordance to the modified Sgarbossa criteria increased sensitivity for diagnosis of any MI (Table 2; p < 0.05).
Conclusions: Terminal T-wave concordance is a sensitive marker of NSTEMI in LBBB. When added to the modified Sgarbossa criteria, this criterion significantly increases the sensitivity of ECG diagnosis of acute MI in LBBB.
Author Disclosures: K.W. Dodd: None. K.D. Elm: None. S.W. Smith: None.
- © 2014 by American Heart Association, Inc.