| Autor: |
Pastore G; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy. gian.past@libero.it., Maines M; Department of Cardiology, Rovereto General Hospital, Rovereto, Italy., Marcantoni L; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Lanza D; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Zanon F; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Noventa F; Department of Molecular Medicine, University of Padua, Padova, Italy., Corbucci G; Boston Scientific Italy, Milan, Italy., Rigatelli G; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Baracca E; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Zuin M; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Picariello C; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Carraro M; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Conte L; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Roncon L; Department of Cardiology, Rovigo General Hospital, 140, Viale Tre Martiri, 45100, Rovigo, Italy., Barold SS; Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA. |
| Abstrakt: |
Non-left bundle branch block (non-LBBB) remains an uncertain indication for cardiac resynchronization therapy (CRT). Non-LBBB includes right bundle branch block (RBBB) and non-specific LV conduction delay (NSCD), two different electrocardiogram (ECG) patterns which are not generally considered to be associated with LV conduction delay as judged by the invasive assessment of the Q-LV interval. We evaluated whether a novel ECG interval (QR-max index) correlated with the degree of LV conduction delay regardless of the type of non-LBBB ECG pattern, and could, therefore, predict CRT response. In 173 non-LBBB patients on CRT (92 NSCD, 81 RBBB), the QR-max index was measured as the maximum interval from QRS onset to R-wave offset in the limb leads. The correlation between QR-max index and Q-LV interval and the impact of the QR-max index on time to first heart failure hospitalization during 3-year follow-up were assessed. Q-LV correlated better with the QR-max index than with QRSd, particularly in the RBBB group (r = 0.91; p < 0.001 vs. r = 0.19; p < 0.089), while the correlations were r = 0.79 (p < 0.01) and r = 0.68 (p < 0.01), respectively, in the NSCD group. In both groups, the QR-max index was significantly more able than QRSd to identify CRT responders (AUC 0.825 vs. 0.576; p = 0.0008 in RBBB; AUC 0.738 vs. 0.701; p = 0.459 in NSCD). A QR-max index exceeding a cutoff value of 120 ms was associated with CRT response, with predictive values of 86.8 and 81.4% in RBBB and NSCD, respectively. The QR-max index reflects the degree of LV electrical delay regardless of QRS duration in RBBB and NSCD patients and is a useful indicator of suitability for CRT in non-LBBB patients. |
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