Sinha Santosh Kumar, Bhagat Kush, Asif Mohammad, Singh Karandeep, Sachan Mohit, Mishra Vikas, Afdaali Nasar, Jha Mukesh Jitendra, Kumar Ashutosh, Singh Shravan, Sinha Rupesh, Khanra Dibbendhu, Thakur Ramesh, Varma Chandra Mohan, Krishna Vinay, Pandey Umeshwar
Department of Cardiology, LPS Institute of Cardiology, G.S.V.M. Medical College, Kanpur, Uttar Pradesh 208002, India.
Cardiol Res. 2016 Aug;7(4):140-145. doi: 10.14740/cr495w. Epub 2016 Sep 5.
Left ventricular (LV) dyssynchrony frequently occurs in patients with heart failure (HF). QRS ≥ 120 ms is a surrogate marker of electrical dyssynchrony, which occurs in only 30% of HF patients. In contrary, in those with normal QRS (nQRS) duration, LV dyssynchrony has been reported in 20-50%. This study was carried out to investigate the role of fragmented QRS (fQRS) on the surface electrocardiography (ECG) as a marker of electrical dyssynchrony to predict the presence of significant intraventricular dyssynchrony (IVD) by subsequent echocardiographic assessment.
A total of 226 consecutive patients with non-ischemic cardiomyopathy were assessed for fQRS on surface ECG as defined by presence of an additional R wave (R prime), notching in nadir of the S wave, notching of R wave, or the presence of more than one R prime (fragmentation) in two contiguous leads corresponding to a major myocardial segment. Tissue Doppler imaging (TDI) was performed in the apical views (four-chamber, two-chamber and long-axis) to analyze all 12 segments at both basal and middle levels. Time-to-peak myocardial sustained systolic (Ts) velocities were calculated. Significant systolic IVD was defined as Ts-SD > 32.6 ms as known as "Yu index".
Of the total patients, 112 had fQRS (49.5%), while 114 had nQRS (50.5%) with male dominance (M/F = 71:29). Majority of patients were in NYHA class II (n = 122, 54%) followed by class III (n = 83; 37%), and class IV (n = 21; 9%). There were no significant differences among both groups for baseline parameters except higher QRS duration (102.42 ± 14.05 vs. 91.10 ± 13.75 ms; P = 0.001), higher Yu index (35.64 ± 12.79 vs. 20.45 ± 11.17; P = 0.01) and number of patients with positive Yu index (78.6% vs. 21.1%; P = 0.04) in group with fQRS compared with group with nQRS. fQRS complexes had 84.61% sensitivity and 80.32% specificity with positive predictive value of 78.6% and negative predictive value of 85.9% to detect IVD. On detailed segmental analysis for fQRS distribution, inferior segment had maximum (37%), followed by anterior (23%), lateral (19%), inferior and lateral (11%), anterior and inferior (8%), and anterior and lateral (2%). Among 104 patients with significant dyssynchrony, 88 patients (84.6%) had fQRS in the dyssynchronic segment.
Fragmentation of QRS complex is an important predictor of electro-mechanical dyssynchrony. It is also helpful in localizing the dyssynchronous segment. In future, larger studies may be carried out to investigate the role of fQRS as a predictor of response to cardiac resynchronization therapy (CRT) in this subgroup of HF patients with narrow QRS.
心力衰竭（HF）患者常出现左心室（LV）不同步。QRS≥120 ms是电不同步的替代标志物，仅30%的HF患者出现该情况。相反，在QRS正常（nQRS）的患者中，据报道LV不同步发生率为20%-50%。本研究旨在探讨体表心电图（ECG）上碎裂QRS（fQRS）作为电不同步标志物的作用，通过后续超声心动图评估预测显著的室内不同步（IVD）的存在。
连续纳入226例非缺血性心肌病患者，评估其体表ECG上的fQRS，fQRS定义为在对应主要心肌节段的两个相邻导联中出现额外的R波（R'）、S波最低点切迹、R波切迹或多个R'（碎裂）。采用心尖视图（四腔心、两腔心和长轴）进行组织多普勒成像（TDI），分析基底和中间水平的所有12个节段。计算心肌持续收缩期峰值时间（Ts）速度。显著收缩期IVD定义为Ts-SD>32.6 ms，即“Yu指数”。
在所有患者中，112例有fQRS（49.5%），114例有nQRS（50.5%），男性占优势（男/女=71:29）。大多数患者为纽约心脏协会（NYHA）II级（n = 122，54%），其次是III级（n = 83；37%）和IV级（n = 21；9%）。两组间基线参数无显著差异，但fQRS组的QRS时限更长（102.42±14.05 vs. 91.10±13.75 ms；P = 0.001）、Yu指数更高（35.64±12.79 vs. 20.45±11.17；P = 0.01）以及Yu指数阳性患者数更多（78.6% vs. 21.1%；P = 0.04）。fQRS复合波检测IVD的敏感性为84.61%，特异性为80.32%，阳性预测值为78.6%，阴性预测值为85.9%。对fQRS分布进行详细节段分析，下壁节段最多（37%），其次是前壁（23%）、侧壁（19%）、下壁和侧壁（11%）、前壁和下壁（8%）以及前壁和侧壁（2%）。在104例有显著不同步的患者中，88例（84.6%）在不同步节段有fQRS。
QRS复合波碎裂是机电不同步的重要预测指标。它也有助于定位不同步节段。未来，可能需要开展更大规模的研究，以探讨fQRS作为该窄QRS HF患者亚组心脏再同步治疗（CRT）反应预测指标的作用。
