Comparison of the Effects of Right Atrial, Right Ventricular Apex and Atrioventricular Sequential Pacing on Myocardial Oxygen Consumption and Cardiac Efficiency: A Laboratory Investigation*

Baller, D.; Wolpers, H. G.; Zipfel, J.; Bretschneider, H. J.; Hellige, G.

doi:10.1111/j.1540-8159.1988.tb05998.x

Cited by 90 publications

(37 citation statements)

References 32 publications

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“…This explains that observed efficiency of metabolic to mechanical energy conversion is lower during RV pacing than during atrial pacing (Baller et al, 1988).…”

Section: Electro-mechanicsmentioning

confidence: 66%

Cardiac resynchronization: Insight from experimental and computational models

Kerckhoffs

Lumens

Vernooy

et al. 2008

Progress in Biophysics and Molecular Biology

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Cardiac resynchronization therapy (CRT) is a promising therapy for heart failure patients with a conduction disturbance, such as left bundle branch block. The aim of CRT is to resynchronize contraction between and within ventricles. However, about 30% of patients do not respond to this therapy. Therefore, a better understanding is needed for the relation between electrical and mechanical activation. In this paper, we focus on to what extent animal experiments and mathematical models can help in order to understand the pathophysiology of asynchrony to further improve CRT.

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“…This explains that observed efficiency of metabolic to mechanical energy conversion is lower during RV pacing than during atrial pacing (Baller et al, 1988).…”

Section: Electro-mechanicsmentioning

confidence: 66%

Cardiac resynchronization: Insight from experimental and computational models

Kerckhoffs

Lumens

Vernooy

et al. 2008

Progress in Biophysics and Molecular Biology

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“…One patient study found that cardiac resynchronization improves efficiency as compared with left bundle-branch block, 9 whereas other studies showed that RV pacing decreased efficiency as compared with atrial pacing. 10,11 It was the aim of this study to compare the long-term (4 months) effects of pacing at the RV apex, RV septum, LV septum, and LV apex in canine hearts by measuring the sequence of electric activation as well as the distribution of myocardial strains, blood flow, pump function, and myocardial efficiency. In addition, it was investigated how singlesite LV pacing compares with biventricular (BiV) pacing.…”

Section: Clinical Perspective On P 579mentioning

confidence: 99%

mentioning

confidence: 99%

Left Ventricular Septal and Left Ventricular Apical Pacing Chronically Maintain Cardiac Contractile Coordination, Pump Function and Efficiency

Mills

Cornelussen

Mulligan

et al. 2009

Circ: Arrhythmia and Electrophysiology

105

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Background-Conventional right ventricular (RV) apex pacing can lead to adverse clinical outcome associated with asynchronous activation and reduced left ventricular (LV) pump function. We investigated to what extent alternate RV (septum) and LV (septum, apex) pacing sites improve LV electric activation, mechanics, hemodynamic performance, and efficiency over 4 months of pacing. Methods and Results-After AV nodal ablation, mongrel dogs were randomized to receive 16 weeks of VDD pacing at the RV apex, RV septum, LV apex, or LV septum (transventricular septal approach). Electric activation maps (combined epicardial contact and endocardial noncontact) showed that RV apical and RV septal pacing induced significantly greater electric desynchronization than LV apical and LV septal pacing. RV apex and RV septal pacing also significantly increased mechanical dyssynchrony, discoordination (MRI tagging) and blood flow redistribution (microspheres) and reduced LV contractility, relaxation, and myocardial efficiency (stroke work/myocardial oxygen consumption). In contrast, LV apical and LV septal pacing did not significantly alter these parameters as compared with the values during intrinsic conduction. At 16 weeks, acute intrasubject comparison showed that single-site LV apical and LV septal pacing generally resulted in similar or better contractility, relaxation, and efficiency as compared with acute biventricular pacing. Conclusions-Acute and chronic LV apical and LV septal pacing maintain regional cardiac mechanics, contractility, relaxation, and efficiency near native levels, whereas RV apical or RV septal pacing diminish these variables. Acute LV apical and LV septal pacing tend to maintain or improve contractility and efficiency compared with biventricular pacing. (Circ Arrhythmia Electrophysiol. 2009;2:571-579.)Key Words: pacing Ⅲ hemodynamics Ⅲ mapping Ⅲ mechanics Ⅲ oxygen C ompared with normal ventricular activation, conventional right ventricular (RV) apex pacing is associated with asynchronous left ventricular (LV) activation, abnormal contraction, and reduced pump function (for review, see reference 1). 1 These adverse effects have been associated with an increased risk of developing heart failure (for review, see reference 1). 1 Also contributing to this adverse outcome is a reduction in myocardial efficiency during ventricular pacing, which increases total myocardial oxygen demand. Consequently, paced hearts can be expected to be more susceptible to ischemia when coronary reserve is limited, 2 as during coronary artery disease and/or overload of the heart. Clinical Perspective on p 579Several studies have sought alternative pacing sites to improve hemodynamic performance. Because pacing leads are usually implanted transvenously, alternate sites within the RV have been studied most intensively, but results of the various studies are mixed. 3,4 Experimental and clinical studies indicate that LV pacing sites often render better hemodynamic performance than RV pacing sites. [5][6][7] In a previous acute canine stu...

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“…29 This reciprocated stretching of regions within the LV wall causes a less effective and energetically efficient contraction. 30 The hemodynamic consequences of the asynchronous LV contraction are reductions in contractility and relaxation. These changes occur immediately on initiating RVA pacing in humans and animals 11,31 and induction of LBBB in animals.…”

Section: Effects Of Asynchrony On LV Mechanics and Structurementioning

confidence: 99%

Ventricular Pump Function and Pacing

Sweeney

Prinzen

2008

Circ: Arrhythmia and Electrophysiology

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O ptimal cardiac pump function depends on ordered mechanical events that are orchestrated by electrical timing. This electromechanical coupling occurs at multiple anatomic levels: within atria, between atria and ventricles, between ventricles, and especially within the left ventricle (LV). Such disruptions to proper electrical timing result in disordered mechanical events (desynchronization, or "dyssynchrony"), can occur spontaneously or be induced in isolation or in various combinations at any level, and degrade cardiac pump function. These disruptions to normal mechanical ordering occur because of fixed or functional conduction blocks and can be generated by myocardial disease or can be induced by cardiac pacing. The adverse effects of disruption of proper electromechanical coupling at all levels with particular attention to the effects of ventricular conduction delay due to conventional (usually right ventricular apical, RVA) pacing and left bundle-branch block (LBBB) are discussed later. Subsequently, remedies for prevention or treatment are discussed along the same lines. Consequences of Uncoupling atVarious Levels Uncoupling at the Atrial LevelThe right atrium and left atrium are activated nearly simultaneously (within 50 to 80 ms) during sinus rhythm. Preferential sites of interatrial conduction exist at the posteriorsuperior interatrial septum (Bachmann's bundle region), fossa ovalis, and coronary sinus ostium. 1,2 Significant interatrial conduction delays (up to 200 ms or greater) can occur in myopathic atria. Similar conduction delays can be also be induced, or exacerbated, by right atrial pacing. Delayed left atrial contraction can disrupt optimal left-sided atrioventricular (AV) coupling. Severe atrial decoupling and delayed left atrial contraction reverses the left-sided AV contraction sequence, resulting in atrial transport block. 3 This causes increased left atrial pressures, retrograde flow in the pulmonary veins, and counterphysiological neurohormonal responses termed "pseudopacemaker syndrome." 4 -6 Uncoupling at Atrioventricular LevelOptimal AV coupling contributes to ventricular pump function. The normal AV interval results in atrial contraction just before the pre-ejection (isovolumic) period of ventricular contraction that maximizes LV filling (LV end-diastolic pressure, or preload) and cardiac output by the Starling mechanism. This optimal timing relationship maximizes diastolic filling time, reduces diastolic mitral regurgitation (MR), and maintains mean left atrium pressure at low levels. Delayed AV coupling due to conduction delay in the AV node displaces atrial contraction earlier in diastole, which may occur immediately after or even within the preceding ventricular contraction. Atrial contraction before completion of venous return reduces preload and contractile force. A late diastolic LVϾleft atrium pressure gradient may occur, causing diastolic MR and partial closure of the mitral valve, which shortens diastolic filling time. Delayed AV coupling may be worsened or induced by atrial...

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Comparison of the Effects of Right Atrial, Right Ventricular Apex and Atrioventricular Sequential Pacing on Myocardial Oxygen Consumption and Cardiac Efficiency: A Laboratory Investigation*

Cited by 90 publications

References 32 publications

Cardiac resynchronization: Insight from experimental and computational models

Cardiac resynchronization: Insight from experimental and computational models

Left Ventricular Septal and Left Ventricular Apical Pacing Chronically Maintain Cardiac Contractile Coordination, Pump Function and Efficiency

Ventricular Pump Function and Pacing

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