Browsing by Author "Meyers, H Pendell"
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Item Open Access Evaluation of T-Wave Morphology in Patients With Left Bundle Branch Block and Suspected Acute Coronary Syndrome.(The Journal of emergency medicine, 2016-09) Meyers, H Pendell; Jaffa, Elias; Smith, Stephen W; Drake, Weiying; Limkakeng, Alexander TT-wave morphology in the setting of left bundle branch block (LBBB) has been proposed as an indicator of myocardial ischemia.We sought to identify T-wave morphology findings in patients with LBBB that predict non-ST-segment elevation myocardial infarction (NSTEMI). We hypothesized that two or more contiguous leads with concordant T waves would be predictive of NSTEMI.This was a retrospective cohort study performed by chart review in a tertiary care center emergency department. We identified a consecutive cohort who presented with LBBB and symptoms consistent with acute coronary syndrome. Exclusion criteria were diastolic blood pressure > 120 mm Hg, heart rate > 130 beats/min, positive pressure ventilation, potassium > 5.5 mEq/L, and cardiac arrest without prearrest electrocardiogram (ECG) available. We collected ECGs and classified T waves into five categories based on morphology, blinded to clinical outcome. Clinical outcome data were collected blinded to ECG findings. Those with ECG diagnostic of STEMI by modified Sgarbossa criteria were excluded from the primary analysis, which was sensitivity and specificity of two or more contiguous leads with concordant T waves for NSTEMI.There were 246 patients included. Mean age was 73 years; 160 (65%) were female, and 32 had myocardial infarction. Thirty percent had two or more contiguous precordial leads with partially or completely concordant T waves. For NSTEMI, the sensitivity and specificity of this finding were 19% (95% confidence interval [CI] 8-37) and 68% (95% CI 61-74).We found no clinically useful relationship between T-wave concordance and myocardial infarction in our patient population. Future investigation of LBBB T-wave morphology should focus on alternative populations and findings.Item Open Access Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study.(American heart journal, 2015-12) Meyers, H Pendell; Limkakeng, Alexander T; Jaffa, Elias J; Patel, Anjni; Theiling, B Jason; Rezaie, Salim R; Stewart, Todd; Zhuang, Cassandra; Pera, Vijaya K; Smith, Stephen WThe modified Sgarbossa criteria were proposed in a derivation study to be superior to the original criteria for diagnosing acute coronary occlusion (ACO) in left bundle branch block (LBBB). The new rule replaces the third criterion (5 mm of excessively discordant ST elevation [STE]) with a proportion (at least 1 mm STE and STE/S wave ≤-0.25). We sought to validate the modified criteria.This retrospective case-control study was performed by chart review in 2 tertiary care center emergency departments (EDs) and 1 regional referral center. A billing database was used at 1 site to identify all ED patients with LBBB and ischemic symptoms between May 2009 and June 2012. In addition, all 3 sites identified LBBB ACO patients who underwent emergent catheterization. We measured QRS amplitude and J-point deviation in all leads, blinded to outcomes. Acute coronary occlusion was determined by angiographic findings and cardiac biomarker levels, which were collected blinded to electrocardiograms. Diagnostic statistics of each rule were calculated and compared using McNemar's test.Our consecutive cohort search identified 258 patients: 9 had ACO, and 249 were controls. Among the 3 sites, an additional 36 cases of ACO were identified, for a total of 45 ACO cases and 249 controls. The modified criteria were significantly more sensitive than the original weighted criteria (80% vs 49%, P < .001) and unweighted criteria (80% vs 56%, P < .001). Specificity of the modified criteria was not statistically different from the original weighted criteria (99% vs 100%, P = .5) but was significantly greater than the original unweighted criteria (99% vs 94%, P = .004).The modified Sgarbossa criteria were superior to the original criteria for identifying ACO in LBBB.