Cardiac output response and peripheral oxygen extraction during exercise among symptomatic hypertrophic cardiomyopathy patients with and without left ventricular outflow tract obstruction

Critoph, Christopher; Patel, Vimal; Mist, Bryan; Elliott, Perry

doi:10.1136/heartjnl-2013-304914

Cited by 20 publications

(14 citation statements)

References 26 publications

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“…Our studies in patients from a family carrying the R403Q mutation in myosin heavy chain (MHC) revealed a 43% reduction in forward CK flux at rest, indicating reduced metabolic reserve (Abraham et al, 2013). A recent study by Critoph et al revealed reduced cardiac reserve secondary to blunted increase in cardiac output, in HCM patients undergoing exercise stress testing (Critoph et al, 2014). NMR studies in mice with R403Q-MHC (Spindler et al, 1998) and R92-TNT (Javadpour et al, 2003; He et al, 2007) mutations verified impaired myocardial energetics during inotropic stimulation.…”

Section: Evidence Of Hcm As a Metabolic Diseasementioning

confidence: 99%

Hypertrophic cardiomyopathy: a heart in need of an energy bar?

Vakrou

Abraham

2014

Front. Physiol.

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Hypertrophic cardiomyopathy (HCM) has been recently recognized as the most common inherited cardiovascular disorder, affecting 1 in 500 adults worldwide. HCM is characterized by myocyte hypertrophy resulting in thickening of the ventricular wall, myocyte disarray, interstitial and/or replacement fibrosis, decreased ventricular cavity volume and diastolic dysfunction. HCM is also the most common cause of sudden death in the young. A large proportion of patients diagnosed with HCM have mutations in sarcomeric proteins. However, it is unclear how these mutations lead to the cardiac phenotype, which is variable even in patients carrying the same causal mutation. Abnormalities in calcium cycling, oxidative stress, mitochondrial dysfunction and energetic deficiency have been described constituting the basis of therapies in experimental models of HCM and HCM patients. This review focuses on evidence supporting the role of cellular metabolism and mitochondria in HCM.

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Section: Evidence Of Hcm As a Metabolic Diseasementioning

confidence: 99%

Hypertrophic cardiomyopathy: a heart in need of an energy bar?

Vakrou

Abraham

2014

Front. Physiol.

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“…Because diastolic dysfunction reduces the filling of the left ventricle, the heart cannot pump enough blood to satisfy the needs of the body when exercising, thus causing damage to the heart due to exercise intolerance and raised LVFP [ 25 , 26 ]. However, it is also possible that the cause of exercise intolerance might be secondary to the inability of the stroke volume to increase appropriately because of abnormal sarcomeric protein causing abnormal contractility and reduced inotropic reserve [ 26 , 27 ]. We observed that HCM patients had higher E/Em, VE/VCO2 slope and lower VO2max.…”

Section: Discussionmentioning

confidence: 99%

Left ventricular filling pressure assessed by exercise TDI was correlated with early HFNEF in patients with non-obstructive hypertrophic cardiomyopathy

Xu²,

Gao

et al. 2014

BMC Cardiovasc Disord

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BackgroundHypertrophic cardiomyopathy (HCM) patients are more susceptible to suffer from heart failure with normal ejection fraction (HFNEF). Therefore, it is critical to evaluate the relationship between left ventricular filling pressure (LVFP) and HFNEF, even if a large proportion of HCM patients have normal LVFP at rest. The objective was to assess the correlation between exercise tissue Doppler imaging (TDI) and early HFNEF in HCM patients by treadmill exercise echocardiography combined with cardiopulmonary exercise test (CPET).MethodTwenty-seven non-obstructive HCM patients and 31 age- and gender-matched healthy volunteers were enrolled in this study. All subjects underwent treadmill exercise echocardiography combined with CPET. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were analyzed before and after exercise.ResultFive HCM patients had normal LVFP at rest and increased after exercise. For this subgroup, the relationship between minute ventilation and carbon dioxide production (VE/VCO2 slope) and NT-proBNP levels were higher compared with controls and the subgroup with normal resting and stress LVFP, but was similar to the subgroup with elevated LVFP both at rest and after exercise.ConclusionElevated LVFP after exercise suggested the occurrence of early HFNEF in patients with non-obstructive HCM.

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“…Myocardial cells collected from patients subjected to surgical myectomy had a defective response to stretch in vitro irrespective of the mutated gene (Sequeira et al, 2013 ). During exercise, HCM patients failed to increase stroke volume in part due to this defect (Critoph et al, 2014 ). An MYL3 HCM mutation in a mouse study affected the frequency range at which the heart can operate efficiently due to alteration of the stretch-activation response (Vemuri et al, 1999 ).…”

Section: Mechanical Flaws In Hcm Patientsmentioning

confidence: 99%

Mechanical aberrations in hypetrophic cardiomyopathy: emerging concepts

et al. 2015

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Hypertrophic cardiomyopathy is the most common monogenic disorder in cardiology. Despite important advances in understanding disease pathogenesis, it is not clear how flaws in individual sarcomere components are responsible for the observed phenotype. The aim of this article is to provide a brief interpretative analysis of some currently proposed pathophysiological mechanisms of hypertrophic cardiomyopathy, with a special emphasis on alterations in the cardiac mechanical properties.

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Cardiac output response and peripheral oxygen extraction during exercise among symptomatic hypertrophic cardiomyopathy patients with and without left ventricular outflow tract obstruction

Abstract: Cardiac reserve is reduced in HCM because of failure of SV augmentation. LVOTO exacerbates this abnormal response, but haemodynamic responses vary significantly. Non-invasive exercise haemodynamic assessment may improve understanding of symptoms and help tailor therapy.

Cited by 20 publications

References 26 publications

Hypertrophic cardiomyopathy: a heart in need of an energy bar?

Hypertrophic cardiomyopathy: a heart in need of an energy bar?

Left ventricular filling pressure assessed by exercise TDI was correlated with early HFNEF in patients with non-obstructive hypertrophic cardiomyopathy

Mechanical aberrations in hypetrophic cardiomyopathy: emerging concepts

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