Changing circadian variation of transient myocardial ischemia during the first year after a first acute myocardial infarction

Prevalence and prognostic implications of ST-segment deviations from ambulatory Holter monitoring after ST-segment elevation myocardial infarction treated with either fibrinolysis or primary percutaneous coronary intervention (a Danish Trial in Acute Myocardial Infarction-2 Substudy)

Ambulatory Holter monitoring has been shown to be useful in stratifying cardiovascular risk after acute myocardial infarction. However, it remains unclear whether ST-segment deviations might predict clinical outcomes in a population treated with primary percutaneous coronary intervention (PCI) compared with thrombolysis. Holter monitoring was initiated at discharge from ST-segment elevation myocardial infarction in 958 patients followed for 2,773 patient-years, randomized to immediate revascularization with either fibrinolysis (n=474) or PCI (n=484). The primary end point was all-cause mortality, and the secondary end point was a composite of death, reinfarction, and disabling stroke. The prevalences of ST-segment depression (STd) and ST-segment elevation (STe) were similar in patients treated with fibrinolysis or PCI (both p=NS). During follow-up, 58 patients died (primary PCI vs fibrinolysis hazard ratio 0.74, p=0.25). The secondary end point was reached in 113 patients (primary PCI vs fibrinolysis hazard ratio 0.66, p=0.03). In fibrinolysis-treated patients, mortality and the secondary end point were significantly higher in patients with STe (both end points p<0.001), an association that remained statistically significant after adjustment for age, gender, anterior infarction, beta-blocker treatment, left ventricular systolic function, and STd (p=0.03 and p=0.005, respectively). Significant associations were not observed for STd. In PCI-treated patients, there was no association between either STe or STd and outcome. In conclusion, immediate revascularization with PCI during STe myocardial infarction does not affect the subsequent prevalence of ST-segment deviation compared with fibrinolysis. However, although STe is an independent predictor of mortality and nonfatal major cardiovascular events in patients treated with fibrinolysis, it does not predict outcome after PCI, perhaps because of more complete revascularization.

Characteristics and prognostic importance of ST-segment elevation on Holter monitoring early after acute myocardial infarction

The correlation between episodes of ST-segment elevation on Holter monitoring, clinical characteristics, left ventricular function, exercise testing, and long-term prognosis was determined in 123 consecutive patients 55 +/- 8 years old (mean +/- SD) with a first acute myocardial infarction (AMI). During 36 hours of Holter recording 11 +/- 5 days after AMI, 11 patients (9%) had 91 episodes of ST-segment elevation (group 1), whereas 112 patients had no such episodes (group 2). Most episodes of ST-segment elevation occurred in leads with pathologic Q waves or small, indistinct R waves. Large, anterior Q-wave AMIs were more prevalent in group 1 than in group 2, and in-hospital heart failure also occurred more frequently in group 1 patients (82% vs 23%; p < 0.0005). Regional and global left ventricular function was reduced in group 1 compared with group 2: ejection fraction 33 +/- 11% vs 50 +/- 11% (p = 0.0001). All episodes of ST-segment elevation were asymptomatic and did not correlate with different indicators of myocardial ischemia. Indeed, exercise-induced ST-segment depression was more prevalent in group 2 than in group 1: 57 vs 18% (p < 0.035). Over a mean of 5 years (range 4 to 6) of follow-up, an association between episodes of ST-segment elevation on Holter monitoring and (1) cardiac death (Kaplan-Meier analysis; p < 0.005), and (2) cardiac death and nonfatal reinfarction (Kaplan-Meier analysis; p < 0.025) was found.(ABSTRACT TRUNCATED AT 250 WORDS)