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Effects of increasing afterload on early diastolic dysfunction in hypertrophic non-obstructive cardiomyopathy
G Hausdorf1, V Siglow, C A Nienaber
1Department of Cardiology, University of Hamburg, West Germany.
Insights
Increasing afterload improved early diastolic dysfunction in hypertrophic non-obstructive cardiomyopathy patients. This suggests altered loading conditions contribute to impaired diastolic function in this condition.
Area of Science:
- Cardiology
- Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) is characterized by impaired diastolic function.
- Early diastolic dysfunction is a key feature affecting cardiac filling.
Purpose of the Study:
- To investigate the impact of increased afterload on early diastolic dysfunction in patients with hypertrophic non-obstructive cardiomyopathy.
Main Methods:
- Computer-assisted analysis of digitized M-mode echocardiograms.
- Infusion of angiotensin II to increase afterload and end-systolic pressure.
- Assessment of diastolic parameters including cavity dimensions and filling durations.
Main Results:
- Increasing afterload normalized early diastolic dysfunction, indicated by decreased interval and dimension change between minimal cavity dimension and mitral valve opening.
- The duration of rapid diastolic filling and accompanying dimension change increased with higher afterload.
- End-diastolic dimension and overall diastolic filling remained unchanged despite afterload increase.
Conclusions:
- Altered loading conditions, specifically increased afterload, can improve early diastolic dysfunction in hypertrophic cardiomyopathy.
- This finding highlights the role of loading conditions in the pathophysiology of diastolic impairment in HCM.
Abstract:
The effects of increasing afterload on early diastolic dysfunction in 10 patients with hypertrophic non-obstructive cardiomyopathy were studied by computer assisted analyses of digitised M mode echocardiograms. Infusion of angiotensin II increased the end systolic pressure by a mean (SD) of 36.2 (10.3) mm Hg. As the afterload increased early diastolic dysfunction tended to become more normal: the interval and the change in dimension between minimal cavity dimension and mitral valve opening decreased and the duration of rapid diastolic filling and the accompanying change in dimension increased. None the less, the end diastolic dimension and thus the overall diastolic filling remained unchanged. Impaired early diastolic function in hypertrophic cardiomyopathy is at least partly caused by altered loading conditions.