Left ventricular leads used in cardiac resynchronization therapy for heart failure patients

Abstract

Cardiac resynchronization therapy (CRT) has been introduced as a treatment for selected heart failure patients, specifically those with symptomatic heart failure, left ventricular (LV) dysfunction, and intraventricular conduction delays. CRT is delivered by use of an implanted device and leads positioned in the right atrium, right ventricle, and left ventricle. In the early stages of CRT development, researchers affixed epicardial electrodes to the left ventricle by means of subxiphoid, thoracoscopic, or major surgical procedure. Currently there are a number of transvenous LV leads available that have undergone substantial evaluation. Reports indicate that such leads can be positioned safely by cannulating the coronary sinus and inserting the lead into the venous system. The leads are reported to have acceptable pacing/sensing thresholds and complication rates. Because of individual variations in the cardiac and venous anatomy, as well as sharp angulations in the venous system, maneuverability is an important consideration in lead selection.

A New Endocardial “Over‐the‐Wire” or Stylet‐Driven Left Ventricular Lead:

“…The implant success rate of the Corox OTW lead was 89% is consistent with other observations 4,14 . The ability to switch between OTW and stylet‐driven techniques during implantation offers procedural flexibility to the physician.…”

“…A key challenge in cardiac resynchronization therapy (CRT) is the implantation of the left ventricular (LV) lead, primarily inserted via the coronary sinus (CS) 1,2 . When, defined as LV lead placement in a CS tributary on the LV wall regardless of location, LV implant success rate rarely exceeds 90% 1–12 . This rate is even lower if defined as the ability to place the LV lead at the optimal, targeted site.…”

“…By comparison, the implantation of right ventricular and atrial leads is associated with nearly 100% implant success rate and much shorter procedure and fluoroscopy times. Furthermore, LV leads dislodge more frequently than right ventricular leads and are associated with a two‐ to three‐fold higher mean long‐term pacing threshold, 2–11 reducing the pacing safety margin, pacemaker battery drain and, in some patients, increasing the risk of phrenic nerve stimulation.…”

Three-dimensional visualisation of coronary sinus ostium from the inside right atrium perspective

“…Another qualification of Thebesian valve based on 2D CT imaging was proposed by Mlynarski et al [6] Visualisation of the coronary venous system was underestimated for years mostly due to its lack of clinical usefulness. However, because of some electrophysiology procedures like cardiac resynchronisation therapy, percutaneous mitral annuloplasty, or ablation, its visualisation has become very important due to the necessity of CS cannulation [7][8][9]. While 20 years ago most of the papers about the visualisation of the coronary veins reported post mortem examinations, today electrophysiologists require in vivo imaging [10].…”