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Recovery of load-induced left ventricular diastolic dysfunction by coenzyme Q10: echocardiographic study
1Department of Pediatrics, Fukuoka University, Japan.
Insights
Load-induced cardiac dysfunction (LCD) affects systolic and diastolic performance, particularly in children with mitral valve prolapse (MVP). Coenzyme Q10 (CoQ) therapy improved both systolic and diastolic functions, suggesting CoQ supports energy-dependent cardiac processes.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Biochemistry
Background:
- Load-induced cardiac dysfunction (LCD) is characterized by decreased left ventricular (LV) systolic performance under afterload stress, often seen in children with mitral valve prolapse (MVP).
- Diastolic function, crucial for cardiac energetics, has been less explored in LCD.
- This study investigates LV diastolic responses to stress in LCD patients before and after coenzyme Q10 (CoQ) therapy.
Purpose of the Study:
- To examine left ventricular (LV) diastolic response patterns to stress in patients with load-induced cardiac dysfunction (LCD).
- To evaluate the effects of coenzyme Q10 (CoQ) therapy on LV diastolic function in LCD patients.
- To compare diastolic performance in LCD patients with healthy controls and asymptomatic children with mitral valve prolapse (MVP).
Main Methods:
- Echocardiographic diastolic indices (D-E slope, E-F slope, maximal diastolic endocardial velocity) were used.
- Thirty subjects (aged 9-16) were divided into four groups: normals, LCD patients, LCD patients post-CoQ therapy, and asymptomatic MVP children.
- Handgrip (HG) stress was applied to assess cardiac response under loading conditions.
Main Results:
- Patients with LCD exhibited higher resting ejection fraction and diastolic indices, which decreased significantly with HG stress.
- Normal hearts, LCD hearts post-CoQ therapy, and MVP hearts showed similar increases in these indices with HG stress.
- Coenzyme Q10 (CoQ) therapy improved both systolic and diastolic dysfunctions in LCD patients.
Conclusions:
- Diastolic performance in normal and LCD hearts mirrors systolic performance under varying load conditions.
- Coenzyme Q10 (CoQ) effectively improved both load-induced systolic and diastolic dysfunctions in LCD patients.
- The rapid resolution of diastolic dysfunction with CoQ suggests it targets a common bioenergetic process in cardiac contraction and relaxation, rather than mechanical stiffness.
Unlabelled:
Load-induced cardiac dysfunction (LCD), in which a supernormal left ventricular (LV) systolic performance at rest decreases due to an afterload challenge, usually occurs among children with mitral valve prolapse (MVP). However, diastolic performance is also important because relaxation, like contraction, is based on a process that requires energy. The aim of this study was to examine LV diastolic response patterns to stress in patients with LCD before and after coenzyme Q10 (CoQ) therapy and in controls. The D-E slope, E-F slope and maximal diastolic endocardial velocity were used as echographic diastolic indices. Thirty subjects, aged 9-16 years, were divided into four groups: group 1, 10 normals; group 2, 10 patients with LCD; group 3, the same 10 as in group 2, who recovered with CoQ, 3.0-3.4 mg/kg/day for 7 days; group 4, 10 asymptomatic children with MVP. The heart rate, both at rest and during handgrip (HG), showed little intergroup difference. Only in group 2, were the ejection fraction and all the diastolic indices greater than in the other groups, but these became subnormal with HG. In the other groups, these indices increased with HG to a similar extent, although resting values were smaller than in group 2.
In Conclusion:
(1) in normal hearts and in hearts with LCD, diastolic performance mimicked systolic performance both in resting and loading conditions; (2) CoQ improved not only the load-induced systolic but also the diastolic dysfunctions in a similar time-course, and (3) mechanical stiffness of the cardiac tissue may not be a cause of load-induced diastolic dysfunction, because the dysfunction was quickly resolved with CoQ therapy. CoQ may be a key substance which affects a common bioenergetic process in contraction and relaxation, to keep these functions normal.