September 15, 1995Circulation
Alterations in Ultrasonic Backscatter During Exercise-Induced Myocardial Ischemia in Humans
Key result
Transient, exercise-induced ischemia significantly altered all ultrasonic backscatter indexes in the septum of patients with LAD stenosis compared to rest values and healthy controls.
Why the study?
Does exercise-induced myocardial ischemia alter ultrasonic backscatter parameters in patients with single left anterior descending coronary stenosis?
Population
19 patients with single left anterior descending coronary stenosis and 15 healthy subjects (total n=34)
Comparison
Supine stress test with ultrasonic backscatter… vs Rest state, recovery state, normally perfused…
Design
Cohort
Follow-up
30 minutes
Authors
Discussion
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Member takes
Implication
May support backscatter indexes as ischemia markers in LAD stenosis; leaves open clinical validation in prospective studies.
Key Points
- To determine whether transient, exercise-induced myocardial ischemia produces detectable alterations in ultrasonic backscatter parameters in human myocardium.
- Assessed 19 patients with isolated left anterior descending coronary stenosis and 15 healthy control subjects.
- Performed ultrasonic backscatter imaging (parasternal long-axis view) at baseline rest, immediately following a supine exercise stress test, and at 30-minute recovery.
- Calculated five integrated backscatter parameters from midmyocardial regions across the cardiac cycle, comparing the ischemic septum against the normally perfused posterior wall and healthy controls.
- All five backscatter indexes in the septum were significantly altered immediately after exercise in patients with stenosis, while no changes occurred in their posterior wall or in control subjects.
- Exercise-induced ischemia caused a blunting of cyclic integrated backscatter variation, an increased phase shift relative to the R wave, and an increase in overall myocardial reflectivity.
- All altered backscatter parameters fully normalized to baseline values by the 30-minute recovery evaluation.
Study Design
Type
Observational (n=34)
Structured PICO
Does exercise-induced myocardial ischemia alter ultrasonic backscatter parameters in patients with single left anterior descending coronary stenosis?
P
Population
34 participants, comprising 19 patients with single left anterior descending coronary stenosis and 15 healthy subjects, evaluated at rest, post-exercise, and 30 minutes later.
E
Exposure
Supine stress test (exercise-induced ischemia) with ultrasonic backscatter analysis
C
Comparator
Rest state, recovery state (30 minutes post-exercise), normally perfused posterior wall, and healthy control group
O
Outcome
Ultrasonic backscatter parameter changes (maximum-minimum difference, amplitude and phase of the first harmonic Fourier fitting, phase-weighted amplitude, and time-averaged integrated backscatter difference from rest)surrogate
Transient exercise-induced myocardial ischemia causes detectable changes in ultrasonic backscatter parameters, which can be measured noninvasively.
Cite This Study
Vitale et al. (1995) conducted an observational in Myocardial ischemia / single left anterior descending coronary stenosis (n=34). Exercise-induced myocardial ischemia (supine stress test) vs. Rest values and healthy subjects was evaluated on Ultrasonic backscatter parameters (maximum-minimum difference, amplitude, phase, phase-weighted amplitude, and time-averaged integrated backscatter difference). Transient, exercise-induced ischemia significantly altered all ultrasonic backscatter indexes in the septum of patients with LAD stenosis compared to rest values and healthy controls.