Optimal CRT Implantation—Where and How To Place the Left-Ventricular Lead?

Abstract

Purpose of Review Cardiac resynchronization therapy (CRT) represents a well-established and effective non-pharmaceutical heart failure (HF) treatment in selected patients. Still, a significant number of patients remain CRT non-responders. An optimal placement of the left ventricular (LV) lead appears crucial for the intended hemodynamic and hence clinical improvement. A well-localized target area and tools that help to achieve successful lead implantation seem to be of utmost importance to reach an optimal CRT effect. Recent Findings Recent studies suggest previous multimodal imaging (CT/cMRI/ECG torso) to guide intraprocedural LV lead placement. Relevant benefit compared to empirical lead optimization is still a matter of debate. Technical improvements in leads and algorithms (e.g., multipoint pacing (MPP), adaptive algorithms) promise higher procedural success. Recently emerging alternatives for ventricular synchronization such as conduction system pacing (CSP), LV endocardial pacing, or leadless pacing challenge classical biventricular pacing. Summary This article reviews current strategies for a successful planning, implementation, and validation of the optimal CRT implantation. Pre-implant imaging modalities offer promising assistance for complex cases; empirical lead positioning and intraoperative testing remain the cornerstone in most cases and ensure a successful CRT effect.

Variations of coronary sinus tributaries among patients undergoing cardiac resynchronisation therapy

“…For years, the statement that nearly onethird of CRT patients do not respond to resynchronization therapy has become general knowledge. It is discussed and partially accepted without questioning the reasons [2]. Besides optimal programming of the CRT device, the anatomical structure of the coronary system plays the most crucial role.…”

“…Finally, the attainable vessels were counted for possible LV lead placement. For accessible vessels for the CRT, the size of 5.1 F (1.7 mm) and angle is less than 60° [2] are considered. The size over 1.7 mm was found in 23/26 PVLV and 10/15 LMV in nonischemic-HF and 28/29 and 16/21 in ischemic-HF.…”

Non-invasive estimation of QLV from the standard 12-lead ECG in patients with left bundle branch block

“…Positioning of the LV electrode has long been a main concern for response and is still reported to be associated with outcome ( Kutyifa et al, 2018 ). Further it is suggested that having an overview of the myocardial substrate in terms of fibrosis and scarring ( Butter et al, 2021 ), as well as myocardial activation and coronary venous anatomy before the procedure would be beneficial. This makes it possible to plan the procedure and to aim for placing the LV lead in a coronary sinus branch over a viable myocardial region with late electrical activation.…”

Troubleshooting the difficult left ventricular lead placement in cardiac resynchronization therapy: current status and future perspectives

“…Some of the considerations to be aware of in this process are the following: is it possible to use a quadripolar lead to be placed into a stable position, not prone to dislodgement, and is the lead in an anatomically favorable position to pace the nonapical posterolateral part of the left ventricle? [16,17] To ensure these issues, it is selfevident that a complete overview of the CS anatomy and ability to reach all the possible targets with the delivery tools are imperative.If the implantation technique does not include these options, the operator is often forced to choose a lead to negotiate the given anatomy of the proximal part of the target vein, e.g. use a LV lead with a very wide curve or with an active fixation mechanism in a large diameter and/or noncurved vein, as it is not possible to be certain that the tip of a smaller curved passive fixation lead is fully wedged into a small side branch and thus securely placed (see figure 6).…”