Clinical Research
Cardiac Resynchronization
Noninvasive Electrocardiographic Mapping to Improve Patient Selection for Cardiac Resynchronization Therapy: Beyond QRS Duration and Left Bundle Branch Block Morphology

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Objectives

This study sought to investigate whether noninvasive electrocardiographic activation mapping is a useful method for predicting response to cardiac resynchronization therapy (CRT).

Background

One third of the patients appear not to respond to CRT when they are selected according to QRS duration.

Methods

We performed electrocardiographic activation mapping in 33 consecutive CRT candidates (QRS duration ≥120 ms). In 18 patients, the 12-lead electrocardiographic morphology was left bundle branch block (LBBB), and in 15, it was nonspecific intraventricular conduction disturbance (NICD). Three indexes of electrical dyssynchrony were derived from intrinsic maps: right and left ventricular total activation times and ventricular electrical uncoupling (VEU) (difference between the left ventricular [LV] and right ventricular mean activation times). We assessed the ability of these parameters to predict response, measured using a clinical composite score, after 6 months of CRT.

Results

Electrocardiographic maps revealed homogeneous patterns of activation and consistently greater VEU and LV total activation time (LVTAT) in patients with LBBB compared with heterogeneous activation sequences and shorter VEU and LVTAT in NICD patients (VEU: 75 ± 12 ms vs. 40 ± 22 ms; p < 0.001; LVTAT: 115 ± 21 ms vs. 91 ± 34 ms; p = 0.03). LBBB and NICD patients had similar right ventricular total activation times (62 ± 30 ms vs. 58 ± 26 ms; p = 0.7). The area under the receiver-operating characteristic curve indicated that VEU (area under the curve [AUC]: 0.88) was significantly superior to QRS duration (AUC: 0.73) and LVTAT (AUC: 0.72) for predicting CRT response (p < 0.05). With a 50-ms cutoff value, VEU identified CRT responders with 90% sensitivity and 82% specificity whether LBBB was present or not.

Conclusions

Ventricular electrical uncoupling measured by electrocardiographic mapping predicted clinical CRT response better than QRS duration or the presence of LBBB.

Key Words

cardiac resynchronization therapy
electrocardiography
electrical dyssynchrony
heart failure
ventricular mapping

Abbreviations and Acronyms

AUC
area under the curve
CRT
cardiac resynchronization therapy
ECG
electrocardiography
ECM
electrocardiographic mapping
LBBB
left bundle branch block
LV
left ventricular
LVTAT
left ventricular total activation time
NICD
nonspecific intraventricular conduction disturbance
NYHA
New York Heart Association
ROC
receiver-operating characteristic
RV
right ventricular
RVTAT
right ventricular total activation time
VEU
ventricular electrical uncoupling
VEUSR
ventricular electrical uncoupling square-root transformed

Cited by (0)

Dr. Ploux has received financial support from the “Fédération Française de Cardiologie.” Dr. Lumens has received a grant in the framework of the Dr. E. Dekker program of the Dutch Heart Foundation (NHS-2012T010). This work was supported by the French Government : l'Agence National de la Recherche au titre du programme Investissements d'Avenir (ANR-10-IAHU-04). Drs. Strom and Ramanathan are paid employees and stockholders of CardioInsight Technologies, Inc. Dr. Shah and Dr. Wilkoff are consultants for CardioInsight Technologies, Inc. Dr. Hocini, Dr. Jaïs, and Dr. Haïssaguerre are stockholders of CardioInsight Technologies, Inc. Dr. Wilkoff is on the advisory boards of and has received honoraria from Medtronic, St. Jude Medical, and Spectranetics. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.