Key result
Patients with old anteroseptal myocardial infarction had a significantly prolonged time constant of left ventricular relaxation compared to normal subjects (50 vs 37 msec; p<0.01).
Why the study?
Does old anteroseptal myocardial infarction alter left ventricular wall motion during the isovolumetric relaxation period compared to normal subjects?
Observational (n=17)
Does old anteroseptal myocardial infarction alter left ventricular wall motion during the isovolumetric relaxation period compared to normal subjects?
Patients with old anteroseptal myocardial infarction exhibit asynchronous left ventricular wall motions during the isovolumetric relaxation period, which may impair LV relaxation.
May indicate diastolic impairment after old anteroseptal MI; leaves open whether asynchronous relaxation warrants targeted intervention.
The effect of the left ventricular (LV) regional wall motion during isovolumetric relaxation period (IRP) were studied in 9 patients with old anteroseptal myocardial infarction (OMI) and 8 normal subjects (NOR). There were no significant differences in heart rate, peak LV systolic pressure and peak (+) dP/dt between the groups. LV cavity was divided into the anterior and inferior sides by a long axis, which was equally divided with 3 perpendicular lines, creating 4 areas in each side. The sums of the 2 middle areas in each side were defined as Aa and Ab, respectively. During IRP the pattern of (-) dP/dt at the upstroke phase was convex-downward in OMI, but convex-upward in NOR. Time constant (T) was significantly prolonged in OMI compared with NOR (50 +/- 9 vs 37 +/- 6 msec; p less than 0.01). On NOR, Aa increased significantly after 33.4 msec from peak (-) dP/dt, while Ab remained unchanged. In OMI, Ab increased after 50.1 msec from peak (-) dP/dt, associated with decrease in Aa, suggesting the passive shortening of the anterior wall by the active expansion of the inferior. Such asynchronous LV wall motions during IRP might impair LV relaxation and influence the upstroke pattern of (-) dP/dt.
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YATABE et al. (1989) conducted an observational in Old anteroseptal myocardial infarction (n=17). Old anteroseptal myocardial infarction (OMI) vs. Normal subjects (NOR) was evaluated on Time constant (T) of left ventricular relaxation (p=<0.01). Patients with old anteroseptal myocardial infarction had a significantly prolonged time constant of left ventricular relaxation compared to normal subjects (50 vs 37 msec; p<0.01).
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