Left ventricular endocardial or triventricular pacing to optimize cardiac resynchronization therapy in a chronic canine model of ischemic heart failure

Abstract

Cardiac resynchronization therapy (CRT) is a proven treatment for heart failure but ~30% of patients appear to not benefit from the therapy. Left ventricular (LV) endocardial and multisite epicardial [triventricular (TriV)] pacing have been proposed as alternatives to traditional LV transvenous epicardial pacing, but no study has directly compared the hemodynamic effects of these approaches. Left bundle branch block ablation and repeated microembolizations were performed in dogs to induce electrical dysynchrony and to reduce LV ejection fraction to <35%. LVdP/dt(max) and other hemodynamic indexes were measured with a conductance catheter during LV epicardial, LV endocardial, biventricular (BiV) epicardial, BiV endocardial, and TriV pacing performed at three atrioventricular delays. LV endocardial pacing was obtained with a clinically available pacing system. The optimal site was defined as the site that increased dP/dt(max) by the largest percentage. Implantation of the endocardial lead was feasible in all canines (n = 8) without increased mitral regurgitation seen with transesophageal echocardiography and with full access to the different LV endocardial pacing sites. BiV endocardial pacing increased dP/dt(max) more than BiV epicardial and TriV pacing on average (P < 0.01) and at the optimal site (P < 0.01). There were no significant differences between BiV epicardial and TriV pacing. BiV endocardial pacing was superior to BiV epicardial and to TriV pacing in terms of acute hemodynamic response. Further investigation is needed to confirm the chronic benefit of this approach in humans.

Development of a Technique for Left Ventricular Endocardial Pacing via Puncture of the Interventricular Septum

“…25 LV endocardial pacing may be superior to epicardial pacing at improving hemodynamic response to CRT. 21,[26][27][28][29][30][31][32][33] In part, this could result from better targeting of lead position because an endocardial approach is not constrained by venous anatomy or phrenic nerve stimulation. The lead tip can be steered to the site of latest electric or mechanical activation or site of maximum acute hemodynamic improvement, provided there is no endocardial scarring.…”

Strategies to improve cardiac resynchronization therapy

“…Experiments using a canine model of LBBB did not show significantly better acute haemodynamic response to triventricular pacing than to biventricular pacing. 92,113 By increasing the number of LV pacing electrodes up to seven, LV activation time was substantially reduced. However, compared with single-site LV pacing, the LVdP/ dt max increased only if the haemodynamic benefit with single-site pacing was small ( Figure 5).…”

“…In animal studies, endocardial pacing resulted in better resynchronization of ventricular activation and larger acute haemodynamic effects than with epicardial pacing. 5, 113,114 The increased electrical resynchronization is caused by a shorter activation path length and faster impulse conduction in the endocardial than in the epicardial layers. An additional advantage of the endocardial approach might be that the choice of sites for pacing is larger because of no limitation by the coronary venous anatomy.…”

Tissue Properties of the Fossa Ovalis as They Relate to Transseptal Punctures: A Translational Approach

“…As mentioned above, there are various procedures that require a TSP including left‐sided cardiac ablation, percutaneous mitral valve repair, mitral balloon valvulotomy, left atrial appendage closure, and certain ventricular assist device placements . These procedures along with some newer and future procedures, including left ventricular endocardial pacing and percutaneous mitral and aortic valve implantation, could potentially bring about a greater prevalence of TSPs and thus higher incidences of potential complications . As cardiology procedures have progressed, the range of sizes for transseptal devices has increased.…”