Myocardial salvage for ST-elevation myocardial infarction with terminal QRS distortion and restoration of brisk epicardial coronary flow

Predictive value of a fragmented QRS complex in patients undergoing primary angioplasty for ST elevation myocardial infarction

OBJECTIVES

The aim of this study was to evaluate the prognostic value of fragmented QRS (fQRS) on electrocardiography (ECG) patients with acute ST-segment elevation in myocardial infarction (STEMI), who are undergoing primary percutaneous coronary intervention (PCI).

METHODS

We prospectively enrolled 414 consecutive STEMI patients (mean age of 55.2 ± 12.2 years old, range of 26-91-years old) undergoing primary PCI. The study patients were divided into two groups according to the presence or absence of fQRS as shown by ECG in the first 48 hours. The presence of fQRS group was defined as fQRS(+) (n = 91), and the absence of fQRS group was defined as the fQRS(-) (n = 323) group. Clinical characteristics and the one-year outcome of the primary PCI were analyzed.

RESULTS

The patients in the fQRS(+) group were older (mean age 60.7 ± 12.5 vs. 53.6 ± 11.6 years old, P < 0.001). Higher one-year all-cause mortality rates were observed in the fQRS group upon ECG (23.1% vs. 2.5%, P < 0.001, respectively). When using the Cox multivariate analysis, the presence of fQRS on the ECG was found to be a powerful independent predictor of one-year all-cause mortality (hazard ratio: 5.24, 95% confidence interval: 1.43-19.2, P = 0.01).

CONCLUSIONS

These results suggest that the presence of fQRS on ECG was associated with an increased in-hospital cardiovascular mortality, and one-year all-cause mortality in patients with STEMI who are under primary PCI.

Twenty years of ECG grading of the severity of ischemia

Shortly following an occlusion of an epicardial coronary artery, changes in the surface electrocardiogram (ECG) can be detected. Initially, T waves in leads with their positive poles facing the ischemic zone become positive, tall and symmetrical. Later, ST segment elevation (STE) becomes apparent. If ischemia continues, changes in the terminal portion of the QRS may also be detected. The changes in the terminal portion of the QRS are believed to be caused by prolongation of the electrical conduction in the ischemic zone and reflect severe ischemia due to lack of protection by preconditioning or collateral circulation. Several groups have shown that patients with the QRS changes of grade 3 ischemia have higher mortality, higher incidence of reinfarction and heart failure than patients presenting with only the T and ST changes of grade 2 ischemia, despite equal success in recanalizing the epicardial coronary artery by either thrombolytic therapy or primary percutaneous coronary intervention. Grade 3 ischemia is associated with more rapid progression of necrosis and larger final infarct size. Further studies are needed to better understand the underlying mechanisms that determine the severity of ischemia and how we should use this method based on the standard 12 lead ECG to implement clinical therapeutic decisions.

Myocardial ischemia analysis based on electrocardiogram QRS complex

Electrocardiogram (ECG) is an economic, convenient, and non-invasive detecting tool in myocardial ischemia (MI), and its clinical appearance is mainly exhibited by the changes in ST-T complex. Recently, QRS complex characters were proposed to analyze MI by more and more researchers. In this paper, various QRS complex characters were extracted in ECG signals, and their relationship was analyzed systematically. As a result, these characters were divided into two groups, and there existed good relationship among them for each group, while the poor relationship between the groups. Then these QRS complex characters were applied for statistical analysis on MI, and five characters had significant differences after ECG recording verification, which were: QRS upward and downward slopes, transient heart rate, angle R and angle Q. On the other hand, these QRS complex characters were analyzed in frequency domain. Experimental results showed that the frequency features of RR interval series (Heart Rate Variability, HRV), and QRS barycenter sequence had significant differences between MI states and normal states. Moreover, QRS barycenter sequence performed better.

Data feedback reduces door-to-balloon time in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Current guidelines recommend a goal of door-to-balloon (D2B) time < 90 min for patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). We aim to prospectively determine the effect of data feedback on D2B time and its seven individual components in primary PCI. From December 7, 2007, to June 2, 2009, 116 consecutive patients with STEMI who received PCI within 12 h of symptom onset were enrolled, including 56 patients before and 60 patients after the implementation of data feedback on July 28, 2008. The proportion of patients treated within 90 min increased from 26.8 to 55.0% (p = 0.002). On multivariable analyses, data feedback (OR 5.3, p = 0.003), known coronary artery disease (OR 5.6, p = 0.043), regular hours presentation (OR 3.3, p = 0.048), and arrival by transfer (OR 14.0, p = 0.003) were independent predictors of a D2B time less than 90 min. Median D2B time decreased from 112 min before data feedback to 87 min after data feedback (p < 0.001). The most significant decrease occurred in median door-to-ECG (11 vs. 3 min, p < 0.001), consult-to-cardiologist (5 vs. 3 min, p < 0.001), and puncture-to-balloon (21 vs. 17 min, p = 0.004) time. Data feedback to the emergency department and catheterization laboratory staff decreases D2B time in primary PCI. This simple approach may be the best first step to decrease D2B time in hospitals that are still striving to achieve the goal of D2B time < 90 min.