Hideyuki Hara1, Shinichi Niwano2, Hiroshi Ito3, Masahiro Karakawa4, Junya Ako2. 1. Cardiology, Numazu City Hospital, Shizuoka, Japan; Department of Cardiovascular Medicine, Kitasato University School of Medicine, Kanagawa, Japan. Electronic address: hideyuki@med.kitasato-u.ac.jp. 2. Department of Cardiovascular Medicine, Kitasato University School of Medicine, Kanagawa, Japan. 3. Cardiology, Numazu City Hospital, Shizuoka, Japan. 4. Cardiology, Saiseikai Izuo Hospital, Osaka, Japan.
Abstract
BACKGROUND: The QRS duration does not always reflect the left ventricular (LV) activation delay in patients with ventricular conduction disturbances. The R-wave offset in left chest leads may more closely reflect the LV activation delay than the QRS offset. METHODS: We evaluated 138 cases with left bundle branch block (LBBB, n=11), right BBB (RBBB, n=38), non-specific intraventricular conduction disturbance (n=11), narrow QRS (<120ms, n=56) and right ventricular pacing (n=22). Cases with right axis deviation (120 to 270 degrees) were excluded. The intervals from the QRS onset to the V-waves in coronary sinus bipolar electrograms (QCS) were measured, and the longest interval was defined as the QCSmax. In the 12-lead electrocardiogram, the interval from the QRS onset to the R-wave offset (QR) was measured and then averaged in leads I-aVL, II-III-aVF, V1-V2, V3-V4 and V5-V6. RESULTS: Significant correlations (p<0.05) were found between QCSmax and QR in I-aVL (r=0.83), II-III-aVF (r=0.51) and V5-V6 (r=0.86) in cases with a normal axis (0 to 90 degrees, n=64); and I-aVL (r=0.90), II-III-aVF (r=0.31) and V5-V6 (r=0.69) in cases with left axis deviation (-45 to -89 degrees, n=52). Overall, the QRS duration was also correlated with QCSmax (r=0.72, p<0.001); however, this correlation was weaker than the correlation between QCSmax and QR in I-aVL (r=0.89, p<0.001) due to disparities in RBBB (p<0.001). CONCLUSIONS: The interval from the QRS onset to R-wave offset in the left chest leads reflects the degree of LV activation delay regardless of differences in QRS duration and morphology.
BACKGROUND: The QRS duration does not always reflect the left ventricular (LV) activation delay in patients with ventricular conduction disturbances. The R-wave offset in left chest leads may more closely reflect the LV activation delay than the QRS offset. METHODS: We evaluated 138 cases with left bundle branch block (LBBB, n=11), right BBB (RBBB, n=38), non-specific intraventricular conduction disturbance (n=11), narrow QRS (<120ms, n=56) and right ventricular pacing (n=22). Cases with right axis deviation (120 to 270 degrees) were excluded. The intervals from the QRS onset to the V-waves in coronary sinus bipolar electrograms (QCS) were measured, and the longest interval was defined as the QCSmax. In the 12-lead electrocardiogram, the interval from the QRS onset to the R-wave offset (QR) was measured and then averaged in leads I-aVL, II-III-aVF, V1-V2, V3-V4 and V5-V6. RESULTS: Significant correlations (p<0.05) were found between QCSmax and QR in I-aVL (r=0.83), II-III-aVF (r=0.51) and V5-V6 (r=0.86) in cases with a normal axis (0 to 90 degrees, n=64); and I-aVL (r=0.90), II-III-aVF (r=0.31) and V5-V6 (r=0.69) in cases with left axis deviation (-45 to -89 degrees, n=52). Overall, the QRS duration was also correlated with QCSmax (r=0.72, p<0.001); however, this correlation was weaker than the correlation between QCSmax and QR in I-aVL (r=0.89, p<0.001) due to disparities in RBBB (p<0.001). CONCLUSIONS: The interval from the QRS onset to R-wave offset in the left chest leads reflects the degree of LV activation delay regardless of differences in QRS duration and morphology.
Authors: Eric N Jimenez-Vazquez; Michael Arad; Álvaro Macías; Maria L Vera-Pedrosa; Francisco Miguel Cruz; Lilian K Gutierrez; Ashley J Cuttita; André Monteiro da Rocha; Todd J Herron; Daniela Ponce-Balbuena; Guadalupe Guerrero-Serna; Ofer Binah; Daniel E Michele; José Jalife Journal: Elife Date: 2022-06-28 Impact factor: 8.713