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Does reduced myocardial efficiency in systemic hypertensive-hypertrophy correlate with increased left-ventricular
June-Chiew Han1, Carolyn J Barrett2, Andrew J Taberner3
1Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
Summary
Hypertension-induced heart problems reduce heart efficiency, especially in older rats. This inefficiency is linked to overall heart size, not just wall thickness, offering a potential diagnostic marker.
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanoenergetics
- Hypertensive Heart Disease
Background:
- Elevated blood pressure leads to pathological left ventricular (LV) hypertrophy, a precursor to heart failure.
- Reduced myocardial efficiency is observed in hypertensive hypertrophy, but its correlation with LV wall thickness is unclear.
Purpose of the Study:
- To investigate the relationship between myocardial efficiency and left ventricular (LV) wall thickness in spontaneously hypertensive rats (SHRs).
- To assess the impact of aging on cardiac mechanoenergetic performance in SHRs compared to Wistar controls.
Main Methods:
- Isolated working hearts from adult and aged spontaneously hypertensive rats (SHRs) and Wistar controls were studied.
- Mechanoenergetic performance (flows, work, oxygen consumption) was evaluated across a range of afterloads.
Main Results:
- Cardiac performance and peak efficiency declined with age in both SHRs and controls.
- Aged SHRs exhibited significantly lower peak efficiency compared to age-matched Wistar rats.
- Reduced myocardial efficiency in hypertensive hypertrophy inversely correlated with whole-heart mass, not LV wall thickness.
Conclusions:
- Myocardial efficiency reduction in hypertensive hypertrophy is linked to whole-heart mass, suggesting a potential prognostic and diagnostic clinical tool.
- Aging exacerbates cardiac dysfunction in SHRs, with peak efficiency sharply diminishing during the transition from compensated hypertrophy to heart failure.
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