Is the Left Ventricular Lateral Wall the Best Lead Implantation Site for Cardiac Resynchronization Therapy?

Abstract

Short-term hemodynamic studies consistently report greater effects of cardiac resynchronization therapy (CRT) in patients stimulated from a LV lateral coronary sinus tributary (CST) compared to a septal site. The aim of the study was to compare the long-term efficacy of CRT when performed from different LV stimulation sites. From October 1999 to April 2002, 158 patients (mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful CRT, from the anterior (A) CST in 21 patients, the anterolateral (AL) CST in 37 patients, the lateral (L) CST in 57 patients, the posterolateral (PL) CST in 40 patients, and the middle cardiac vein (MCV) CST in 3 patients. NYHA functional class, 6-minute walk test, and echocardiographic measurements were examined at baseline, and at 3, 6, and 12 months. Comparisons were made among all pacing sites or between lateral and septal sites by grouping AL + L + PL CST as lateral site (134 patients, 85%) and A + MC CST as septal site (24 patients, 15%). In patients stimulated from lateral sites, LVEF increased from 0.30 to 0.39 (P < 0.0001), 6-minute walk test from 323 to 458 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 82% to 10% (P < 0.0001). In patients stimulated from septal sites, LVEF increased from 0.28 to 0.41 (P < 0.0001), 6-minute walk test from 314 to 494 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 75% to 23% (P < 0.0001). A significant improvement in cardiac function and increase in exercise capacity were observed over time regardless of the LV stimulation sites, either considered singly or grouped as lateral versus septal sites.

Long‐Term Outcomes of Cardiac Resynchronization Therapy Using Apical Versus Nonapical Left Ventricular Pacing

“…Other clinical studies, however, have not been consistent. Gasparini et al found no difference in NYHA class, 6‐minute walking distance, or LVEF between anterior and posterolateral LV lead positions 15. Similar survival was observed for anterior and posterolateral LV lead positions in other observational studies16 and in the COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) study 17.…”

“…We should also consider, however, that these techniques were not used in MADIT‐CRT2 or REVERSE 3. Although fluoroscopy may not permit precise localization of lead position, it has nevertheless been used in randomized controlled trials2, 3, 17 and is routinely used in clinical practice worldwide 15, 16…”

Efecto de la localización del electrodo ventricular izquierdo sobre los parámetros ecocardiográficos de asincronía en pacientes sometidos a terapia de resincronización cardíaca

“…en región lateral en relación con la región anterior 20 , no existe ningún estudio aleatorizado que haya comparado la eficacia de ambas localizaciones sobre el devenir clínico a medio plazo en pacientes sometidos a resincronización.…”

“…Sin embargo, a la vista de estos resultados y a pesar de ser técnicamente más complejo, parece prudente escoger una zona lateral para implantar el electrodo ventricular izquierdo siempre que sea factible 21 . Hay que reseñar, sin embargo, que desde el punto de vista técnico, esto puede no ser posible en más de un 30% de los casos debido a una desfavorable anatomía venosa, a la presencia de elevados umbrales de estimulación, a la inestabilidad del electrodo o a la presencia de estimulación frénica 20 . En este estudio no se han obtenido diferencias en cuanto a la asincronía interventricular, la cual se ha modificado escasamente tras la implantación del dispositivo.…”

Cardiac Resynchronisation Therapy in Heart Failure

“…Accordingly, CS pacing leads are typically placed in midlateral wall positions, frequently over a guideword directed into the selected tributary3.In a study by Gasparini et al the effects of differential pacing sites were evaluated in CRT treated patients, the results were not in favor of lateral wall pacing. Separated from the stimulation site, the clinical and echocardiographic parameters were significantly improved in the most of the patients (36). Thereby, the pacing of an alternate site when leading a lateral wall placement is not technically feasible.…”