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[Recovery process from myocardial stunning after transient ischemia: assessment with pulsed wave Doppler transmitral
1Cardiovascular Division, Osaka Minami National Hospital.
Insights
Myocardial stunning, or systolic dysfunction after ischemia, can impair diastolic function. This study found that diastolic dysfunction may persist longer than systolic dysfunction following transient ischemia in coronary artery disease patients.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Myocardial stunning, characterized by sustained left ventricular systolic dysfunction post-ischemia, is well-documented.
- However, the recovery patterns of left ventricular diastolic function after transient myocardial ischemia remain less understood.
Purpose of the Study:
- To investigate the changes and recovery of left ventricular systolic and diastolic performance following dobutamine-induced transient myocardial ischemia.
- To compare these changes between healthy controls and patients with coronary artery disease (CAD).
Main Methods:
- Utilized two-dimensional echocardiography and pulsed wave Doppler transmitral flow velocity.
- Measurements were taken at baseline, peak dobutamine infusion, and at 20 minutes and 2 hours post-infusion.
- Included 13 control subjects and 34 patients with CAD presenting with chest pain syndrome and normal coronary arteries.
Main Results:
- In controls, dobutamine increased ejection fraction and early diastolic filling velocity, returning to baseline post-infusion.
- In CAD patients, ejection fraction and peak velocity increased with dobutamine but decreased post-infusion, despite stable hemodynamics.
- While ejection fraction improved at 2 hours, peak diastolic filling velocity did not recover to baseline levels.
Conclusions:
- Left ventricular diastolic dysfunction may have a more prolonged recovery course than systolic dysfunction after transient myocardial ischemia.
- Findings suggest potential for sustained diastolic impairment in CAD patients following ischemic events.
Abstract:
Sustained left ventricular systolic dysfunction after transient myocardial ischemia is well known as "myocardial stunning", but little is known about the recovery in left ventricular diastolic function. Changes in left ventricular systolic and diastolic performance following dobutamine-induced ischemia were investigated in 13 patients with chest pain syndrome and normal coronary arteries (control) and 34 patients with coronary artery disease. Two-dimensional echocardiography and pulsed wave Doppler transmitral flow velocity curves were recorded at baseline, after infusion of a peak dose of dobutamine and at 20 min and 2 hours after dobutamine infusion. In control subjects, left ventricular ejection fraction and the peak early diastolic filling velocity increased at the peak dose of dobutamine. At 20 min after the cessation of dobutamine infusion, these values were restored to the baseline levels. In patients with coronary artery disease, ejection fraction and peak velocity increased at the peak dose of dobutamine but decreased at 20 min after infusion compared with baseline values despite the restoration of heart rate and blood pressure. Although ejection fraction increased at 2 hours compared with 20 min after infusion, peak velocity did not increase. Left ventricular diastolic dysfunction may be sustained longer than systolic dysfunction after transient myocardial ischemia.