The greatest benefit of enoxaparin over unfractionated heparin in acute coronary syndromes is achieved in patients presenting with ST-segment changes: the Enoxaparin in Non-Q-Wave Coronary Events (ESSENCE) Electrocardiogram Core Laboratory Substudy

Differences in negative T waves among acute coronary syndrome, acute pulmonary embolism, and Takotsubo cardiomyopathy

AIMS

Negative T waves in precordial leads often occur in patients with acute coronary syndrome (ACS), but are also found in acute pulmonary embolism (APE) and Takotsubo cardiomyopathy (TC). Because the clinical features of these two diseases mimic those of ACS, differential diagnosis is essential to select an appropriate treatment strategy improve outcomes. This study aimed to clarify the differences in negative T waves among ACS, APE and TC.

METHODS AND RESULTS

We studied admission ECGs in 300 patients (198 patients with ACS caused by the left anterior descending coronary artery disease, 81 with APE and 21 with TC). All patients were admitted within 48 h from symptom onset and had negative T waves ≥1.0 mm without ST-segment elevation in leads V1 to V4. The number and maximal amplitude of negative T waves were greatest in patients with TC, followed by in those with ACS, and were lowest in patients with APE (p < 0.001, respectively). The prevalence of negative T waves significantly differed in all 12 leads among the three groups (p < 0.01, respectively). Negative T waves in both leads III and V1 identified APE with 90% sensitivity and 97% specificity. Negative T waves in lead -aVR (i.e., positive T waves in lead aVR) and no negative T waves in lead V1 identified TC with 95% sensitivity and 97% specificity. These values represented the highest diagnostic accuracies.

CONCLUSION

The distributions of negative T waves differed among ACS, APE and TC, and these differences were useful for differentiating among these three diseases.

Long-term prognostic value and therapeutic implications of continuous ST-segment monitoring in acute coronary syndrome

BACKGROUND

In patients with acute coronary syndromes (ACS), recurrent ischemia detected by continuous electrocardiographic monitoring portends a poor outcome. We sought to investigate (1) the additional long-term prognostic value of ST-segment monitoring beyond the validated Global Registry of Acute Coronary Events (GRACE) risk score in ACS and (2) whether ST-segment monitoring can identify patients who benefit from early revascularization.

METHODS

We determined the GRACE risk score (a validated predictor of inhospital mortality) in 681 non-ST-elevation ACS patients enrolled in the Integrilin and Enoxaparin Randomized Assessment of Acute Coronary Syndrome Treatment trial. Continuous ST-segment monitoring in the first 48 hours was analyzed by an automated algorithm and reviewed by a blinded cardiologist. Clinical outcomes were centrally adjudicated in a blinded fashion.

RESULTS

ST-segment shifts were present in 19.1% of 681 patients. After a median follow-up of 30 months, patients with ST-segment shifts had a higher risk of death (17.7% vs 5.8%, log-rank P < .001) and death or myocardial infarction (MI) (24.6% vs 11.1%, log-rank P < .001). In multivariable analysis adjusting for GRACE risk score, the presence of ST-segment shifts remained an independent predictor of death (adjusted hazard ratio = 2.37, 95% CI 1.38-4.09, P = .002) and death/MI (adjusted hazard ratio = 1.93, 95% CI 1.25-3.00, P = .003). Inhospital revascularization was independently associated with a lower risk of death/MI among patients with ST-segment shifts but not among those without (P for interaction = .02).

CONCLUSIONS

Continuous ST-segment monitoring provides incremental prognostic information beyond the validated GRACE risk score determined on presentation and identifies high-risk patients who benefit from early revascularization. This simple and valuable clinical tool may be useful in the routine management of ACS.

Evidence-based medical therapy of patients with acute coronary syndromes

Acute coronary syndromes (ACS) present a major health challenge in modern medicine. With new clinical trials being conducted, our knowledge of latest therapies for ACS continually evolves. In this article, we review currently available medical therapies and provide evidence-based rationale for current pharmacologic therapies. Among the antiplatelet therapies, aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitors demonstrate significant efficacy in reducing morbidity and mortality. Among the anticoagulants, unfractionated heparin and low molecular weight heparin, particularly enoxaparin sodium, remain the hallmarks of therapy against which newer anticoagulants are often compared. Bivalirudin has recently showed significant efficacy in decreasing cardiovascular events and mortality, but with potentially less risk of bleeding than heparin. Results of trials evaluating warfarin remain inconsistent regarding potential benefits. Finally, fondaparinux sodium, recently tested, shows promise as a powerful yet safe anticoagulant. Fibrinolysis is an acceptable modality for reperfusion if facilities equipped for primary percutaneous revascularization are not available. Regarding anti-ischemic therapy, beta-adrenoceptor antagonists and nitrates remain critical in the early management of ACS. Inhibitors of the renin-angiotensin-aldosterone system have also shown significant reductions in the morbidity and mortality of patients presenting with ACS, particularly in patients with left ventricular dysfunction and clinical heart failure, with ACE inhibitors being first-line agents and angiotensin receptor antagonists being a reasonable substitute if ACE inhibitors are not tolerated. Among the lipid-lowering therapies, statins (HMG-CoA reductase inhibitors) have been documented as being the most well tolerated and most efficacious therapies for ACS patients and data exist that they should be administered early in ACS management. Studies evaluating combination therapy (antiplatelet drugs, beta-adrenoceptor antagonists, ACE inhibitors, and lipid-lowering agents) show a clear benefit in mortality in patients with known coronary artery disease. Efforts to improve these key evidence-based medical therapies are numerous and include such programs as the American College of Cardiology's Guidelines Applied in Practice, international patient registries such as the Global Registry of Acute Coronary Events, and studies such as CRUSADE. Finally, patients with diabetes mellitus pose a challenge to clinicians both in terms of their glycemic control and in their apparent relative resistance to antiplatelet therapy. Studies involving ACS patients suggest that stringent glycemic control may result in benefits in both morbidity and mortality.