Etiologies and predictors of ST-segment elevation myocardial infarction

The Busan Regional CardioCerebroVascular Center Project��s Experience Over a Decade in the Treatment of ST-segment Elevation Myocardial Infarction

Objectives

The Regional CardioCerebroVascular Center (RCCVC) project was initiated to improve clinical outcomes for patients with acute myocardial infarction or stroke in non-capital areas of Korea. The purpose of this study was to evaluate the outcomes and issues identified by the Busan RCCVC project in the treatment of ST-segment elevation myocardial infarction (STEMI).

Methods

Among the patients who were registered in the Korean Registry of Acute Myocardial Infarction for the RCCVC project between 2007 and 2019, those who underwent percutaneous coronary intervention (PCI) for STEMI at the Busan RCCVC were selected, and their medical data were compared with a historical cohort.

Results

In total, 1161 patients were selected for the analysis. Ten years after the implementation of the Busan RCCVC project, the median door-to-balloon time was reduced from 86 (interquartile range [IQR], 64–116) to 54 (IQR, 44–61) minutes, and the median symptom-to-balloon time was reduced from 256 (IQR, 180–407) to 189 (IQR, 118–305) minutes (p<0.001). Inversely, the false-positive PCI team activation rate increased from 0.6% to 21.4% (p<0.001). However, the 1-year cardiovascular death and major adverse cardiac event rates did not change. Even after 10 years, approximately 75% of the patients had a symptom-to-balloon time over 120 minutes, and approximately 50% of the patients underwent inter-hospital transfer for primary PCI.

Conclusions

A decade after the implementation of the Busan RCCVC project, although time parameters for early reperfusion therapy for STEMI improved, at the cost of an increased false-positive PCI team activation rate, survival outcomes were unchanged.

ECG clues for false ST-segment elevation myocardial infarction activations

BACKGROUND

Rapid diagnosis of ST-segment elevation myocardial infarction (STEMI) is crucial for appropriate management. Catheterization for a false STEMI activation has risks including exposure to contrast agent and radiation, increased healthcare costs and delay in treatment of the primary medical condition.

PATIENTS AND METHODS

This was a single center retrospective study including all 'cath alerts' between January 2012 and December 2015. 'Cath alert' is a term used to activate the interventional cardiology team when STEMI is suspected by the emergency department physicians based on review of the initial ECG. We reviewed all STEMI alerts to understand ECG differences between true and false STEMI.

RESULTS

Our study population (N = 361) included 221 (61%) men and 140 (39%) women, with average age 60 ± 4.2 years. Among the 361 STEMI alerts, 82 (22.7%) did not have acute coronary syndrome. Common ECG causes of misdiagnosis included left ventricular hypertrophy (LVH, found in 40/82, 49%), early repolarization changes (20/82, 24%), right bundle branch block (RBBB) (13/82, 16%), and Brugada pattern (3/82, 4%). Multivariate regression analysis showed that LVH and RBBB were independent predictors of nonacute coronary syndrome false STEMI (odds ratio: 0.54; 95% confidence interval: 0.32-0.93; P = 0.03 for LVH, and odds ratio: 0.26, 95% confidence interval: 0.1-0.62, P = 0.004 for RBBB).

CONCLUSION

The incidence of false STEMI alerts was almost 23% at our center. This number might be reduced with additional training of emergency department physicians in ECG interpretation, and recognition of common causes of misdiagnosis such as LVH, early repolarization changes, RBBB, and Brugada pattern.

Risk score to predict false-positive ST-segment elevation myocardial infarction in the emergency department: a retrospective analysis

Background

The best treatment approach for ST-segment elevation myocardial infarction (STEMI) is prompt primary percutaneous coronary intervention (PCI). However, some patients show ST elevation on electrocardiography (ECG), but do not have myocardial infarction. We sought to identify the frequency of and to develop a prediction model for false-positive STEMI.

Methods

This study was conducted in the emergency departments (EDs) of two hospitals using the same critical pathway (CP) protocol to treat STEMI patients with primary PCI. The prediction model was developed in a derivation cohort and validated in internal and external validation cohorts.

Results

Of the CP-activated patients, those for whom ST elevation did not meet the ECG criteria were excluded. Among the patients with appropriate ECG patterns, the incidence of false-positive STEMI in the entire cohort was 16.3%. Independent predictors extracted from the derivation cohort for false-positive STEMI were age < 65 years (odds ratio [OR], 2.54; 95% confidence interval [CI], 1.35–4.89), no chest pain (OR, 12.04; 95% CI, 5.92–25.63), atypical chest pain (OR, 7.40; 95% CI, 3.27–17.14), no reciprocal change (OR, 4.80; 95% CI, 2.54–9.51), and concave-morphology ST elevation (OR, 14.54; 95% CI, 6.87–34.37). Based on the regression coefficients, we established a simplified risk score. In the internal and external validation cohorts, the areas under the receiver operating characteristic curves for our risk score were 0.839 (95% CI, 0.724–0.954) and 0.820 (95% CI, 0.727–0.913), respectively; the positive predictive values were 40.9% and 22.0%, respectively; and the negative predictive values were 94.9% and 96.7%, respectively.

Discussion

Our prediction model would help them make rapid decisions with better rationale.

Conclusion

We devised a model to predict false-positive STEMI. Larger-scale validation studies are needed to validate our model, and a prospective study to determine whether this model is effective in reducing improper primary PCI in actual clinical practice should be performed.

Frequency and factors associated with inappropriate for intervention cardiac catheterization laboratory activation

BACKGROUND

Current guidelines emphasize timely coronary intervention with a door to balloon time of ≤90min for favorable survival impact after STEMI. Efforts to achieve these targets may result in unnecessary emergent angiography for inappropriate activations.

OBJECTIVE

Evaluate the frequency, trend and factors which are significantly associated with inappropriate for intervention cardiac catheterization laboratory (CCL) activation.

METHODS

We analyzed 1764 consecutive emergent CCL activation for possible ST segment elevation myocardial infarction (STEMI) between 7/2005 and 8/2013. Inappropriate for intervention activation was defined as negative STEMI (incorrect diagnosis: insignificant coronary lesion, not requiring any intervention) and inappropriate patients (true STEMI but poor CCL candidacy).

RESULTS

Inappropriate for intervention CCL activation occurred in 317 patients (17.9%): 292 incorrect diagnosis (negative STEMI diagnosis), 25 inappropriate patients, with no difference in the frequency based on time of the day (18.6% regular hours vs. 17.6% off-hours, p=0.6). On multivariable analysis, female gender (OR 1.9 [1.2-3.0]), African American race (OR 1.9[1.3-2.7]), and prior coronary artery bypass graft surgery (OR 3.6 [2.3-5.5]) were significantly associated with incorrect diagnosis (negative STEMI diagnosis) (all p<0.005) and hyperlipidemia (OR 0.2 [0.1-0.3]), tobacco use (OR 0.2 [0.1-0.3]), and stroke/TIA (OR 0.2 [0.1-0.4]) had a significant inverse association (all p<0.001). ST Elevation with no reciprocal depression and pericarditis/myocarditis were the most common ECG finding and etiology respectively.

CONCLUSION

Inappropriate for intervention CCL activation is not uncommon and should be closely monitored to maximize resource utilization. Females, African American patients with few or no risk factors and patients presenting ST elevation but no reciprocal depression constitute a population that may require attention.

QTc Prolongation after Ventricular Septal Defect Repair in Infants

Background and Objectives

Prolonging of the corrected QT interval (QTc) has been reported after cardiac surgery in some studies. However, there have not been many studies on infant open cardiac surgery for ventricular septal defect (VSD) repair. This study was performed to define the changes in QTc and to find related post-surgery factors in this patient group.

Subjects and Methods

From 2008 to 2012, 154 infants underwent VSD repair at the Severance Cardiovascular Hospital. This study includes 105 of these cases. QTc was measured in these patients retrospectively. Demographic data and peri-procedural data, such as Aristotle score, cross-clamp time and bypass time, were analyzed. The exclusion criteria included multiple and small VSDs that underwent direct closure.

Results

Mean post-operative QTc was increased compared to the pre-operative measurements (from 413.6±2.3 to 444.9±2.5, p<0.001). In multiple linear regression, the comprehensive Aristotle score was associated with increasing QTc (p=0.047). The incidence of transient arrhythmia, such as atrial tachycardia, junctional ectopic tachycardia, premature atrial contraction, or premature ventricular contraction, was associated with QTc prolongation (p=0.005). Prolonged QTc was also associated with cross-clamp time (p=0.008) and low weight (p=0.042). Total length of stay at the intensive care unit and intubation time after surgery were not associated with QTc prolongation.

Conclusion

Prolonged QTc could be seen after VSD repair in infants. This phenomenon was associated with peri-procedural factors such as the Aristotle score and cross-clamp time. Patients with QTc prolongation after cardiac surgery had an increased tendency towards arrhythmogenicity in the post-operative period.