Open AccessGlobal and Regional Ventricular Repolarization Study by Body Surface Potential Mapping in Patients with Left Bundle‐Branch Block and Heart Failure Undergoing Cardiac Resynchronization Therapy
Author(s) -
Douglas Roberto A. G.,
Samesima Nelson,
Filho Martino M.,
Pedrosa Anísio A.,
Nishioka Silvana A. D.,
Pastore Carlos A.
Publication year - 2012
Publication title -
annals of noninvasive electrocardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.494
H-Index - 48
eISSN - 1542-474X
pISSN - 1082-720X
DOI - 10.1111/j.1542-474x.2012.00500.x
Subject(s) - medicine , cardiac resynchronization therapy , cardiology , repolarization , qt interval , ejection fraction , heart failure , left bundle branch block , right bundle branch block , sinus rhythm , electrocardiography , ventricular repolarization , atrial fibrillation , electrophysiology
Background: The controversial effects promoted by cardiac resynchronization therapy (CRT) on the ventricular repolarization (VR) have motivated VR evaluation by body surface potential mapping (BSPM) in CRT patients. Methods: Fifty‐two CRT patients, mean age 58.8 ± 12.3 years, 31 male, LVEF 27.5 ± 9.2, NYHA III‐IV heart failure with QRS181.5 ± 14.2 ms, underwent 87‐lead BSPM in sinus rhythm (BASELINE) and biventricular pacing (BIV). Measurements of mean and corrected QT intervals and dispersion, mean and corrected T peak end intervals and their dispersion, and JT intervals characterized global and regional (RV, Intermediate, and LV regions) ventricular repolarization response. Results: Global QTm (P < 0.001) and QTc m (P < 0.05) were decreased in BIV; QTm was similar across regions in both modes (P = ns); QTc m values were lower in RV/LV than in Intermediate region in BASELINE and BIV (P < 0.001); only RV/Septum showed a significant difference (P < 0.01) in the BIV mode. QTD values both of BASELINE (P < 0.01) and BIV (P < 0.001) were greater in the Intermediate than in the LV region. CRT effect significantly reduced global/regional QTm and QTc m values. QTD was globally decreased in RV/LV (Intermediate: P = ns). BIV mode significantly reduced global T peak end mean and corrected intervals and their dispersion. JT values were not significant. Conclusions: Ventricular repolarization parameters QTm, QTc m , and QTD global/regional values, as assessed by BSPM, were reduced in patients under CRT with severe HF and LBBB. Greater recovery impairment in the Intermediate region was detected by the smaller variation of its dispersion.