Effects of electric stimulations applied during absolute refractory period on cardiac function of rabbits with heart failure

Haizhu, Zhang; Cui, Changcong; Hu, Dayi

doi:10.1007/s11596-010-0204-3

Cited by 3 publications

(3 citation statements)

References 19 publications

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“…However, the effects of NES on global contractility, as measured by LV dP/dt max, were positive during NES (23.3 ± 12%, 26.0 ± 9.3%, and 31.3 ± 12.5% for anterior, posterior, and both respectively). Acute improvements in global functional measures have also been demonstrated in dogs with LV dysfunction (through serial coronary micro-embolizations) using the biphasic waveform after 10 min to 6 h of stimulation [24, 25] and more recently in rabbits with heart failure due to myocardial infarction [26]. …”

Section: Electrical Stimulation On the Heartmentioning

confidence: 99%

Electrical modalities beyond pacing for the treatment of heart failure

et al. 2010

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In this review, we report on electrical modalities, which do not fit the definition of pacemaker, but increase cardiac performance either by direct application to the heart (e.g., post-extrasystolic potentiation or non-excitatory stimulation) or indirectly through activation of the nervous system (e.g., vagal or sympathetic activation). The physiological background of the possible mechanisms of these electrical modalities and their potential application to treat heart failure are discussed.

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Section: Electrical Stimulation On the Heartmentioning

confidence: 99%

Electrical modalities beyond pacing for the treatment of heart failure

et al. 2010

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“…These new technologies are developed as a treatment for refractory systolic heart failure of, through electrical stimulation of small, undetectable or sub-threshold electrical impulses to increase and/or synchronize myocardial contractility. Numerous studies have demonstrated the usefulness of CCM to evoke cardiac inotropic effect [24,25,26]. The ability of CCM to improve cardiac function is believed mainly due to enhanced local contraction force and electrical stimulation in different parts of the myocardium may have different efficacies on cardiac function.…”

Section: Discussionmentioning

confidence: 99%

“…The ability of CCM to improve cardiac function is believed mainly due to enhanced local contraction force and electrical stimulation in different parts of the myocardium may have different efficacies on cardiac function. It is not yet clear and is even still confusing as to what parts of the myocardium stimuli should be applied to achieve the best effects [25,26]. In this study, we compared left ventricle anterior wall stimulation (LVP-CCM) as a mono-ventricular CCM with bi-ventricular CCM.…”

Section: Discussionmentioning

confidence: 99%

Biventricular Pacing Cardiac Contractility Modulation Improves Cardiac Contractile Function via Upregulating SERCA2 and miR-133 in a Rabbit Model of Congestive Heart Failure

Ning

Qi²,

Li³

et al. 2014

Cell Physiol Biochem

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Objective: To compare the effects of biventricular electrical pacing and conventional single-ventricular pacing for cardiac contractility modulation (CCM) on cardiac contractile function and to delineate the underlying molecular mechanisms. Methods: Forty rabbits were divided into four groups before surgery: healthy control, HF sham, HF left ventricular pacing CCM (LVP-CCM), and HF biventricular pacing CCM (BVP-CCM) groups with n=10 for each group. A rabbit model of chronic heart failure was established by ligating ascending aortic root of rabbits. Then electrical stimulations during the absolute refractory period were delivered to the anterior wall of left ventricle in the LVP-CCM group and on the anterior wall of both left and right ventricles in the BVP-CCM group lasting six hours per day for seven days. Changes in ventricular structure, cardiac function and electrocardiogram were monitored before and after CCM stimulation. Results: Compared with the sham-operated group, heart weight, heart weight index, LV end-systolic diameter (LVESD), LV end-diastolic diameter (LVEDD) in the LVP-CCM and BVP-CCM groups were significantly decreased (p<0.05), while LV ejection fraction (LVEF) and fractional shortening fraction (FS) were increased (p<0.05). Notably all these changes were consistently found to be greater in BVP-CCM than in LVP-CCM. Moreover, plasma BNP levels were highest in the HF sham-control group, followed by the LVP-CCM group, and lowest in the BVP-CCM group (p<0.05). Furthermore, sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2a) protein levels were upregulated by 1.7 and 2.4 fold, along with simultaneous upregulation of a cardiac-enriched microRNA miR-133 levels by 2.6 and 3.3 fold, in LVP-CCM and BVP-CCM, respectively, compared to sham. Conclusions: Biventricular pacing CCM is superior to conventional monoventricular pacing CCM, producing greater improvement cardiac contractile function. Greater upregulation of SERCA2 and miR-133 may account, at least partially, for the improvement by BVP-CCM.

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The acute inotropic effects of cardiac contractility modulation (CCM) are associated with action potential duration shortening and mediated by β1-adrenoceptor signalling

Winter

Brack

2011

Journal of Molecular and Cellular Cardiology

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Despite promising results in clinical trials conducted to date, little is known about how cardiac contractile modulation (CCM) mediated inotropic enhancement occurs and how CCM affects the electrophysiological characteristics of the heart. The aims of the present study were to 1) investigate how the stimulation parameters of the CCM signal and the location of stimulus delivery influence the contractile response, 2) characterise the effect of CCM on ventricular electrophysiology, and 3) investigate the potential physiological mechanisms underlying these acute inotropic and electrophysiological effects. Experiments were conducted in isolated rabbit hearts with simultaneous measurement of ventricular contractility and monophasic action potential duration (MAPD). Biphasic square wave pulses were applied to the left ventricle, timed to coincide with the absolute refractory period. CCM mediated responses were assessed over a range of signal amplitudes (2–30 mA), durations (2–15 ms) and delays from the activation of the locally recorded monophasic action potential (0–30 ms). Responses were assessed during perfusion with the β1-adrenoceptor antagonist metoprolol (1.8 μM) and HMR 1556 (500 nM), an inhibitor of the slow delayed rectifying potassium current. Norepinephrine content was collected and assessed by ELISA from samples of coronary effluent collected during CCM. CCM induced a significant increase in left ventricular pressure (LVP) in a manner dependent upon the amplitude and duration of the CCM signal but independent of the delay of the stimulus within the action potential plateau and was associated with an increase in norepinephrine in coronary effluent (Mean: 46 ± 9 pg/ml). CCM promoted a shortening of MAPD-90% close to the site of stimulation (− 19 ± 3%) but had no effect on those recorded at distant sites (0 ± 1%). The increase in LVP (4.7 ± 1.8 vs. 0.7 ± 0.9%, P < 0.01) and shortening of local MAPD-90% (− 15 ± 3 vs. 1 ± 1%, P < 0.01) was abolished with metoprolol. Perfusion with HMR 1556 caused a significant inhibition of local MAPD shortening (− 27 ± 2 vs. − 21 ± 3 ms, P < 0.05). CCM is associated with a shortening of ventricular MAPD in a manner dependent upon β-adrenoceptor stimulation resulting from catecholamine release, a finding which may be of clinical significance in regard to the development of malignant ventricular arrhythmias. This article is part of a Special Issue entitled Possible Editorial.

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Effects of electric stimulations applied during absolute refractory period on cardiac function of rabbits with heart failure

Cited by 3 publications

References 19 publications

Electrical modalities beyond pacing for the treatment of heart failure

Electrical modalities beyond pacing for the treatment of heart failure

Biventricular Pacing Cardiac Contractility Modulation Improves Cardiac Contractile Function via Upregulating SERCA2 and miR-133 in a Rabbit Model of Congestive Heart Failure

The acute inotropic effects of cardiac contractility modulation (CCM) are associated with action potential duration shortening and mediated by β1-adrenoceptor signalling

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