Continuous and online analysis of heart rate variability

Spectral analysis of heart rate variability provides a probe to assess the function of the sympathetic and parasympathetic nervous systems. Time-frequency analysis of heart rate variability is useful for investigating autonomic nervous function in patients with syncope or non-sustained ventricular tachycardia, or in anaesthesia, etc. In this paper, we developed an algorithm for continuous and online analysis of heart rate variability. The algorithm was simulated and evaluated in MATLAB, and implemented on the digital signal processor. The electrocardiogram signals from MIT/BIH arrhythmia database and one patient with syncope demonstrate the capability of the proposed method in the continuous and online analysis of heart rate variability.     

II导联RWPT标准鉴别宽QRS波的早搏

目的探讨应用Ⅱ导联R波峰时间（RWPT）法对宽QRS波早搏的鉴别诊断价值。方法对已确诊的192例宽QRS波早搏患者，计算应用Ⅱ导联RwPr法对宽QRS波诊断的准确率。结果192例宽QRS波早搏患者中，已确诊的室性早搏130例，室上性早搏伴室内差异传导62例。应用Ⅱ导联RWPT法再鉴别其激动是室性还是室上性伴室内差异传导，发现真阳性112例、假阳性8例、真阴性54例、假阴性18例；敏感度85．38％，特异度87．00％，阳性预测值93．33％，阴性预测值76．39％，准确度86．46％。结论应用Ⅱ导联RWPT法鉴别宽QRS波早搏有较高的敏感度、特异度。     

右室起搏电极参数随诊及其对心功能的影响

目的通过比较右室间隔部起搏和右室心尖部起搏电极参数和心功能的变化趋势，选择更为有利的起搏方式。方法选取心尖部起搏21例和间隔部起搏21例，术时、12个月、24个月随诊，分别作心脏彩色多普勒超声检查，记录左室舒张末期内径（LVEDD）、左室射血分数（LVEF）、起搏心电图测量Ⅱ导联QRS波时限、抽血查氨基末端脑钠肽前体（NT-proBNP）、起搏器程控仪记录阈值、阻抗、R波感知进行比较。结果间隔部组比心尖部组QRS时限和电极阻抗小，随起搏时间延长QRS时限、NT-proBNP、LVEDD增加、LVEF（％）下降，心尖部组表现较为明显。结论间隔部起搏QRS波较窄，LVEF（％）下降缓慢、LVEDD（mm）和NT-proBNP（pg／m1）升高缓慢，与心尖部起搏比较，心室同步性好、可延缓心功能减退，是右室起搏较好的选择部位。     

Coronary sinus lead delay index for optimization of coronary sinus lead placement

Aim

Optimization of coronary sinus (CS) lead position to the latest activated left ventricular (LV) area is important to increase cardiac resynchronization therapy (CRT) response. We aimed to detect the relationship between coronary sinus lead delay index (CSDI) and echocardiographic, electrocardiographic response to CRT treatment.

Methods

We prospectively included 137 consecutive patients with heart failure (HF) diagnosis, QRS ≥ 120 ms, left bundle branch block (LBBB), New York Heart Association score (NYHA) II–IV, LV ejection fraction (LVEF) <35% and scheduled for CRT (84 male, 53 female; mean age 65.1 ± 10.1 years). Echocardiographic CRT response was defined as ≥15% reduction in LV end‐systolic volume (LVESV). CS lead sensing delay was calculated as the time interval from the onset of surface QRS wave to the onset of depolarization wave recorded from the CS lead by using the CS pacing lead as a bipolar electrode. CSDI was calculated by dividing the CS lead sensing delay by the QRS duration.

Results

LVESV reduction was associated with baseline QRS width (r = .257, p = .002), QRS narrowing (r = .396, p < .001), CSDI (r = .357, p < .001), and NT‐proBNP (r = ?0.213, p = .022) in bivariate analysis. In logistic regression analysis, CSDI was found to be only independent parameter for predicting significant LVESV reduction (Beta = 0.318, p < .001). CSDI was also found to be significantly associated with LVEF increase (r = .244, p = .004) and QRS narrowing (r = .178, p = .046).

Conclusion

CSDI may be used as a marker to predict the favorable response to CRT. It may be useful to integrate CSDI to CRT implantation procedure in order to minimize nonresponders.

     

Left bundle branch–optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group

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室上性宽QRS波群心动过速的临床分析

目的对自发室上性宽QRS波群心动过速的临床特征、心电图特点进行分析,并用Brugada4步诊断法与室速进行鉴别诊断,评价其敏感性及特异性。方法选择入院时为心动过速的患者,符合窦性P波消失、心室率>100bpm且QRS波群时限≥0.12s,心脏电生理检查明确诊断后,采用单盲法回顾性分析12导联体表心电图的形态学特征,独立做出诊断后,计算Brugada4步诊断法的特异性和敏感性并评价其实用性,同时分析其临床特征及血液动力学改变。结果入选50例室上性宽QRS波群心动过速患者,46例诊断为室上速伴束支阻滞或心室内差异性传导,特异性92%,敏感性100%;心室率<180bpm组与心室率>180bpm组,两组的平均收缩压、平均舒张压及平均动脉压(平均动脉压=舒张压 1/3脉压)均有差别,心室率较快组血压较低,p值<0.05,差别有统计学意义。结论Brugada法对室上性宽QRS波群心动过速的鉴别诊断有重要意义,正确的诊断和及时的处理对患者至关重要。     

右室双部位起搏与双室同步起搏的急性血液动力学对比研究

比较右室双部位 (RV Bi)起搏和双室 (BiV)同步起搏对血液动力学的影响 ,并与右室心尖部 (RVA)、右室流出道 (RVOT)、左室基底部 (LVB)起搏相比较 ,明确双部位起搏是否优于单部位起搏。 15例患者中病窦综合征 8例、Ⅲ度房室阻滞 7例。分别行RVA、RVOT、LVB、RV Bi、BiV起搏 (VVI,6 0～ 90次 /分 ) ,测定心输出量 (CO)和心脏指数(CI)、肺毛细血管嵌顿压 (PCWP)和QRS波时限 (QRSd)。结果 :①与RVA起搏相比 ,RVOT、LVB、RV Bi、BiV起搏CI分别增加了 7.5 %、11.3%、15 .5 %和 17.2 % ,PCWP分别降低了 14.9%、10 .3%、2 1.7%和 2 0 .0 % (P均 <0 .0 1)。②RV Bi、BiV起搏较RVOT、LVB起搏的CO、CI增高而PCWP降低 (P均 <0 .0 5 )。③RV Bi与BiV起搏、RVOT与LVB起搏之间CO、CI和PCWP无显著差异。④RVOT、RV Bi、BiV起搏的QRSd(分别为 12 8± 11,111± 16 ,10 3± 13ms)较RVA起搏 (146± 18ms)时显著缩短 (P≤ 0 .0 0 1) ,而LVB起搏 (142± 15ms)与RVOT、RVA起搏时无显著差异。结论 :RV Bi起搏和BiV同步起搏的急性血液动力学效果无明显差异 ,但双部位起搏的效果明显优于单部位起搏 ;双部位起搏的QRSd也比单部位起搏明显缩短