Left ventricular septal and left ventricular apical pacing chronically maintain cardiac contractile coordination, pump function and efficiency.

Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands.
Circulation Arrhythmia and Electrophysiology (Impact Factor: 5.95). 10/2009; 2(5):571-9. DOI: 10.1161/CIRCEP.109.882910
Source: PubMed

ABSTRACT 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.
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.
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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiac resynchronization therapy (CRT) emerged 2 decades ago as a useful form of device therapy for heart failure associated with abnormal ventricular conduction, indicated by a wide QRS complex. In this Review, we present insights into how to achieve the greatest benefits with this pacemaker therapy. Outcomes from CRT can be improved by appropriate patient selection, careful positioning of right and left ventricular pacing electrodes, and optimal timing of electrode stimulation. Left bundle branch block (LBBB), which can be detected on an electrocardiogram, is the predominant substrate for CRT, and patients with this conduction abnormality yield the most benefit. However, other features, such as QRS morphology, mechanical dyssynchrony, myocardial scarring, and the aetiology of heart failure, might also determine the benefit of CRT. No single left ventricular pacing site suits all patients, but a late-activated site, during either the intrinsic LBBB rhythm or right ventricular pacing, should be selected. Positioning the lead inside a scarred region substantially impairs outcomes. Optimization of stimulation intervals improves cardiac pump function in the short term, but CRT procedures must become easier and more reliable, perhaps with the use of electrocardiographic measures, to improve long-term outcomes.
    Nature Reviews Cardiology 05/2014; · 10.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Device therapy in children has undergone several changes over the last few years due to developments in technology as well new approaches to preservation of ventricular function in paediatric pacing, novel data on pacing lead survival, inclusion of cardiac resynchronisation therapy and accumulating experience with the implantable cardioverter-defibrillator. Despite these developments device therapy in children is still associated with significant complications mainly due to patient size, growth and underlying structural heart disease. The amount of available data on therapy outcomes is much smaller than in their adult counterparts and prospective randomized studies are completely missing. Thus device therapy has to be cautiously tailored to individual patient needs having in mind the specific situation of expected decades of treatment. Avoidance of complications and potential harm precluding successful therapy continuation in the future should be one of the main principles.
    Herzschrittmachertherapie & Elektrophysiologie 07/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Right ventricular (RV) pacing may induce left ventricular (LV) dysfunction: neonates and infants with isolated congenital complete/advanced atrioventricular block (CCAVB) are at high risk of developing RV pacing-induced LV dyssynchrony, remodelling, and dysfunction. We prospectively investigated whether LV pacing results in normal LV function and good clinical status in the short/medium term.
    Europace 08/2014; · 3.05 Impact Factor

Full-text (2 Sources)

Available from
May 16, 2014