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Enhanced postischemic dysfunction selective to subendocardium in conscious dogs with LV hypertrophy
1Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston 02115.
The American Journal of Physiology
|February 1, 1994
Summary
Left ventricular hypertrophy (LVH) in dogs modestly increased myocardial stunning in the subendocardium after coronary arterial occlusion (CAO) and reperfusion (CAR), leading to impaired global LV function.
Area of Science:
- Cardiology
- Physiology
- Experimental Medicine
Background:
- Left ventricular hypertrophy (LVH) is a common cardiovascular condition.
- The impact of LVH on myocardial stunning following ischemia-reperfusion injury is not fully understood.
- Understanding these effects is crucial for managing patients with hypertrophic hearts.
Purpose of the Study:
- To compare the effects of coronary arterial occlusion (CAO) and reperfusion (CAR) on myocardial function in normal dogs versus dogs with induced LVH.
- To investigate the regional differences in myocardial stunning and recovery within the left ventricle.
- To assess the influence of LVH on global left ventricular (LV) dynamics and coronary flow reserve post-ischemia.
Main Methods:
- Induction of LVH in conscious dogs via ascending aortic banding.
- Measurement of global LV dynamics and regional wall motion before and after a 15-min CAO and 24-h CAR.
- Assessment of systemic hemodynamics, LV systolic pressure, and circumferential fiber shortening.
- Evaluation of regional myocardial dysfunction in the subendocardium and subepicardium.
- Determination of coronary flow reserve using intravenous adenosine.
Main Results:
- Dogs with LVH exhibited a greater decrease in LV systolic pressure during CAO compared to normal dogs.
- Following CAR, LVH dogs showed sustained depression in LV systolic pressure and fiber shortening.
- Regional myocardial dysfunction recovery was prolonged in the subendocardium of LVH dogs.
- Coronary flow reserve was depressed in the subendocardium of LVH dogs, unaffected by CAR.
- Myocardial stunning was modestly increased in the subendocardium of LVH dogs.
Conclusions:
- Myocardial stunning after brief CAO and CAR is modestly enhanced in the subendocardium of dogs with LVH.
- This regional dysfunction contributes to a modest impairment of global LV function in LVH.
- LVH alters the response to ischemia-reperfusion injury, particularly affecting subendocardial function and recovery.