Myocardial Contractility: Historical and Contemporary Considerations

Muir, William W.; Hamlin, Robert L.

doi:10.3389/fphys.2020.00222

Cited by 23 publications

(19 citation statements)

References 160 publications

(211 reference statements)

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“…In the heart, ischemia/reperfusion (I/R) stress markedly decreases the contractile activity (Duncker et al, 1998), especially in the aging hearts (Fares & Howlett, 2010). The myocardium is in high demand for energy to maintain the cardiac contractions (Muir & Hamlin, 2020). Mitochondria are the main energy producer in cardiomyocytes for contractile function by mitochondria oxidative phosphorylation (OXPHOS) (Bers, 2002).…”

Section: Introductionmentioning

confidence: 99%

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Zhang

Fedorova

et al. 2021

Aging Cell

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Section: Introductionmentioning

confidence: 99%

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Zhang

Fedorova

et al. 2021

Aging Cell

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“…Cardiac function relies not only on the ability of the sarcomere to contract and relax, but also on the preservation of the shape and structure of the organ 1 . The mechanical properties of the myocardial tissue determine how sarcomeres shorten and develop force independently of the preexisting loading conditions 2 , 3 .…”

Section: Introductionmentioning

confidence: 99%

Assessment of myocardial viscoelasticity with Brillouin spectroscopy in myocardial infarction and aortic stenosis models

Villalba-Orero

Riobóo

Gontán

et al. 2021

Sci Rep

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Heart diseases are associated with changes in the biomechanical properties of the myocardial wall. However, there is no modality available to assess myocardial stiffness directly. Brillouin microspectroscopy (mBS) is a consolidated mechanical characterization technique, applied to the study of the viscoelastic and elastic behavior of biological samples and may be a valuable tool for assessing the viscoelastic properties of the cardiac tissue. In this work, viscosity and elasticity were assessed using mBS in heart samples obtained from healthy and unhealthy mice (n = 6 per group). Speckle-tracking echocardiography (STE) was performed to evaluate heart deformation. We found that mBS was able to detect changes in stiffness in the ventricles in healthy myocardium. The right ventricle showed reduced stiffness, in agreement with its increased compliance. mBS measurements correlated strongly with STE data, highlighting the association between displacement and stiffness in myocardial regions. This correlation was lost in pathological conditions studied. The scar region in the infarcted heart presented changes in stiffness when compared to the rest of the heart, and the hypertrophied left ventricle showed increased stiffness following aortic stenosis, compared to the right ventricle. We demonstrate that mBS can be applied to determine myocardial stiffness, that measurements correlate with functional parameters and that they change with disease.

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“… 4 10 15 24 The reason for this is still unclear, but contractility itself is not likely to be affected by LV-only stimulation. 25 The increase in LV dP/dt max with LV pre-excitation may relate to stimulation of a larger ventricular mass in the LV electrode region. 26 The distal electrode resulted in higher LV dP/dt max than the proximal electrode.…”

Section: Discussionmentioning

confidence: 99%

Determinants of LV dP/dt_maxand QRS duration with different fusion strategies in cardiac resynchronisation therapy

et al. 2021

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BackgroundWe designed this study to assess the acute effects of different fusion strategies and left ventricular (LV) pre-excitation/post-excitation on LV dP/dtmax and QRS duration (QRSd).MethodsWe measured LV dP/dtmax and QRSd in 19 patients having cardiac resynchronisation therapy (CRT). Two groups of biventricular pacing were compared: pacing the left ventricle (LV) with FUSION with intrinsic right ventricle (RV) activation (FUSION), and pacing the LV and RV with NO FUSION with intrinsic RV activation. In the NO FUSION group, the RV was paced before the expected QRS onset. A quadripolar LV lead enabled distal, proximal and multipoint pacing (MPP). The LV was stimulated relative in time to either RV pace or QRS-onset in four pre-excitation/post-excitation classes (PCs). We analysed the interactions of two groups (FUSION/NO FUSION) with three different electrode configurations, each paced with four different degrees of LV pre-excitation (PC1–4) in a statistical model.ResultsLV dP/dtmax was higher with NO FUSION than with FUSION (769±46 mm Hg/s vs 746±46 mm Hg/s, p<0.01), while there was no difference in QRSd (NO FUSION 156±2 ms and FUSION 155±2 ms). LV dP/dtmax and QRSd increased with LV pre-excitation compared with pacing timed to QRS/RV pace-onset regardless of electrode configuration. Overall, pacing LV close to QRS-onset (FUSION) with MPP shortened QRSd the most, while LV dP/dtmax increased the most with LV pre-excitation.ConclusionWe show how a beneficial change in QRSd dissociates from the haemodynamic change in LV dP/dtmax with different biventricular pacing strategies. In this study, LV pre-excitation was the main determinant of LV dP/dtmax, while QRSd shortens with optimal resynchronisation.

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Myocardial Contractility: Historical and Contemporary Considerations

Cited by 23 publications

References 160 publications

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Assessment of myocardial viscoelasticity with Brillouin spectroscopy in myocardial infarction and aortic stenosis models

Determinants of LV dP/dt_maxand QRS duration with different fusion strategies in cardiac resynchronisation therapy

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Myocardial Contractility: Historical and Contemporary Considerations

Cited by 23 publications

References 160 publications

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Assessment of myocardial viscoelasticity with Brillouin spectroscopy in myocardial infarction and aortic stenosis models

Determinants of LV dP/dtmaxand QRS duration with different fusion strategies in cardiac resynchronisation therapy

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Determinants of LV dP/dt_maxand QRS duration with different fusion strategies in cardiac resynchronisation therapy