Identifying delayed left ventricular lateral wall activation in patients with non-specific intraventricular conduction delay using coronary venous electroanatomical mapping

Abstract

BackgroundDelayed left ventricular (LV) lateral wall activation is considered the electrical substrate that characterises patients suitable for cardiac resynchronisation therapy (CRT). Although typically associated with left bundle branch block, delayed LV lateral wall activation may also be present in patients with non-specific intraventricular conduction delay (IVCD). We assessed LV lateral wall activation in a cohort of CRT candidates with IVCD using coronary venous electroanatomical mapping, and investigated whether baseline QRS characteristics on the ECG can identify delayed LV lateral wall activation in this group of patients.MethodsTwenty-three consecutive CRT candidates with IVCD underwent intra-procedural coronary venous electroanatomical mapping using EnSite NavX. Electrical activation time was measured in milliseconds from QRS onset and expressed as percentage of QRS duration. LV lateral wall activation was considered delayed if maximal activation time measured at the LV lateral wall (LVLW-AT) exceeded 75 % of the QRS duration. QRS morphology, duration, fragmentation, axis deviation, and left anterior/posterior fascicular block were assessed on baseline ECGs.ResultsDelayed LV lateral wall activation occurred in 12/23 patients (maximal LVLW-AT = 133 ± 20 ms [83 ± 5 % of QRS duration]). In these patients, the latest activated region was consistently located on the basal lateral wall. QRS duration, and prevalence of QRS fragmentation and left/right axis deviation, and left anterior/posterior fascicular block did not differ between patients with and without delayed LV lateral wall activation.ConclusionCoronary venous electroanatomical mapping can be used at the time of CRT implantation to determine the presence of delayed LV lateral wall activation in patients with IVCD. QRS characteristics on the ECG seem unable to identify delayed LV lateral wall activation in this subgroup of patients.

Why QRS Duration Should Be Replaced by Better Measures of Electrical Activation to Improve Patient Selection for Cardiac Resynchronization Therapy

“…Instead, the above described technique of coronary venous electro-anatomic mapping can be used at the time of CRT implantation for a more precise characterization of the electrical substrate at only minor prolongation of procedure time (∼20 min) [ 51 , 53 ]. However, ideally the decision whether or not to implant a CRT device is made in advance.…”

Repositioning and optimization of left ventricular lead position in nonresponders to cardiac resynchronization therapy is associated with improved ejection fraction, lower NT-proBNP values, and fewer heart failure symptoms

“…Median procedure and fluoroscopy time for the LV lead reposition procedure was 78 [51-108] minutes and 12 [4][5][6][7][8][9][10][11][12][13][14][15][16][17] minutes, respectively. There were no early complications to the LV lead reposition procedures, but there was 1 late local infection (n 5 1 [4%]), which resulted in extraction of the system and replacement with a right-sided CRT implant (with the LV lead in the same position).…”

Pacing-Correctable Mitral Regurgitation

“…The lack of correlation between anatomic lead location and QLV confirms that the solely anatomy-driven LV lead implantation strategy is suboptimal and it calls for more extensive use of multipolar LV lead with possibly independent pacing cathodes. 22,23 Indeed, in a recent study by van Stipdonk et al, 22 delayed LV lateral wall activation (defined as the area where the maximal activation time measured at the LV lateral wall was >75% of the total QRS duration) was found in approximately half of the patients. In these patients, the location of the latest activated region was more frequently confined to the basal lateral wall, but some individual differences have been observed.…”