Temporal changes of noninvasive electrocardiographic risk factors for Sudden Cardiac Death in Post-Myocardial Infarction Patients with Preserved…

BACKGROUND:

Several noninvasive risk factors (NIRFs) have been proposed for sudden cardiac death risk stratification in post-myocardial infarction(post-MI) patients with preserved ejection fraction (EF). However, it remains unclear if these factors change over time.

We evaluated seven electrocardiographic NIRFs as they were described in the PRESERVE-EF trial in 80 post-MI patients with EF40%, at least 40days after revascularization and 1year later.

Mean patient age was 5610years, and 88% were men. Mean EF was 505%. The prevalence of (a) positive late potentials (27.5% vs. 28.8%, p=.860), (b) >30 premature ventricular complexes/hour (8.8% vs. 11.3%, p=.598), (c) nonsustained ventricular tachycardia (8.8% vs. 5%, p=.349), (d) standard deviation of normal RR intervals <75ms (3.8% vs. 3.8%, p=1.000), (e) QTc derived from 24-hr electrocardiography >440ms (men) or >450ms (women) (17.5% vs. 17.5%, p=1.000), (f) deceleration capacity 4.5ms and heart rate turbulence onset 0% and slope 2.5ms (2.5% vs. 3.8%. p=1.000), and (g) ambulatory T-wave alternans 65V in two Holter channels (6.3% vs. 6.3%, p=1.000) were similar between the two measurements. However, five patients (6.3%) without any NIRFs during the first assessment had at least one positive NIRF at the second assessment and six patients (7.5%) with at least one NIRF at baseline had no positive NIRFs at 1year.

While the prevalence of the examined electrocardiographic NIRFs between the two examinations was similar on a population basis, some patients without NIRFs at baseline developed NIRFs at 1year and vice versa, highlighting the need for risk factor reassessment during follow-up.

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Temporal changes of noninvasive electrocardiographic risk factors for Sudden Cardiac Death in Post-Myocardial Infarction Patients with Preserved...