Progression of heart failure in right univentricular pacing compared to biventricular pacing

Modalities of ventricular pacing for cardiac resynchronization therapy in patients with heart failure: a meta-analysis and systematic review

INTRODUCTION

This meta-analysis evaluated 14 studies which compared clinical and functional outcomes after different cardiac resynchronization therapy (CRT) modalities.

MATERIAL AND METHODS

Relevant studies were selected from the Medline, PubMed, Cochrane, and Google Scholar databases until June 27^th, 2016. We analyzed and compared the clinical outcomes (peak O₂ consumption and LVEF) and functional outcomes (6-min walk distance and quality of life (SF-36)) of HF patients who received different CRT modalities with outcomes in patients who received conventional univentricular therapy.

RESULTS

There was no significant difference in post-treatment 6-min walking distance between the biventricular (BiV) and left/right univentricular (LUV/RUV) groups (standardized difference in means = 0.049, 95% CI: -0.119 to 0.217, p = 0.566), or between the BiV and triventricular (TriV) groups (standardized difference in means = 0.035, 95% CI: -0.270 to 0.340, p = 0.822). Peak O₂ consumption was comparable between BiV and LUV/RUV groups (standardized difference in means = 0.306, 95% CI: -0.002 to 0.614, p = 0.052). Patients in the TriV group had a significant improvement in LVEF compared to the BiV group (standardized difference in means = 0.647, 95% CI: 0.313 to 0.982, p < 0.001).

CONCLUSIONS

TriV CRT is an attractive alternative to univentricular or BiV pacing for heart failure patients. It is necessary to conduct further large randomized trials to validate our present data.

Evaluation of the effects of transvenous pacing site on left ventricular function and synchrony in healthy anesthetized dogs

OBJECTIVE-To compare the acute effects of cardiac pacing from various transvenous pacing sites on left ventricular (LV) function and synchrony in clinically normal dogs. ANIMALS-10 healthy adult mixed-breed dogs. PROCEDURES-Dogs were anesthetized, and dual-chamber transvenous biventricular pacing systems were implanted. Dogs were paced in single-chamber mode from the right atrial appendage (RAA) alone and in dual-chamber mode from the right ventricular apex (RVA), from the left ventricular free wall (LVFW), and simultaneously from the RVA and LVFW (BiV). Standard ECG and echocardiographic measurements, cardiac output measured with the lithium dilution method (LiDCO), and tissue Doppler-derived measurements of LV synchrony were obtained during each of the pacing configurations. RESULTS-Placement of the biventricular pacing systems was possible in 8 of the 10 dogs. The QRS duration was significantly different among all pacing sites, and the order of increasing duration was RAA, BiV, LVFW, and RVA. Pacing sites did not differ with respect to fractional shortening; however, pacing from the RVA resulted in a significantly lower ejection fraction than pacing from all other sites. During RVA and LVFW pacing, LiDCO was significantly lower than that at other sites; there was no significant difference between RAA and BiV pacing with respect to LiDCO. Although the degree of dyssynchrony was significantly lower during pacing from the RAA versus other ventricular pacing sites, it was not significantly different among sites. CONCLUSIONS AND CLINICAL RELEVANCE-Ventricular activation by RAA pacing provided the best LV function and synchrony. Pacing from the RVA worsened LV function, and although pacing from the LVFW improved it, BiV pacing may provide additional improvement.

[Heart failure in 2006]

This article are summarizes the most relevant articles in the field of heart failure including epidemiology, diagnostic and therapeutic issues. Therapy includes drugs, cardiac resinchronization therapy, automatic implantable defibrillator, heart transplantation and cell therapy. Stem cell therapy is feasible and short term data indicates it is safe. However there are unresolved concerns on arrhythmias, restenosis and efficacy. At this point experts recommend that medium-sized randomized controlled trials, using surrogate endpoints, should be carried out to establish the efficacy and safety of this form of treatment.