Jastrzebski Marek
First Department of Cardiology and Hypertension, University Hospital, Cracow, Poland.
Pacing Clin Electrophysiol. 2011 Dec;34(12):1682-6. doi: 10.1111/j.1540-8159.2011.03219.x. Epub 2011 Sep 28.
Left ventricular (LV)-only pacing has a significant effect on delay in depolarization of parts of the ventricles that are likely oversensed in the right atrial channel. The study aimed to assess the impact of ventricular activation sequence on QRS oversensing and far-field endless-loop pacemaker tachycardia (ELT) in patients who received cardiac resynchronization therapy (CRT) devices.
The study examined 102 patients with CRT devices. Oversensing artifacts in the atrial channel were inspected on intracardiac electrograms, and their timing with respect to the beginning of QRS was determined during DDD-right ventricular (RV), DDD-LV, DDD-biventricular (BiV), and AAI pacing modes. The occurrence of ELT during DDD-LV pacing with a postventricular atrial refractory period (PVARP) of 250 ms was also assessed.
The timing of oversensing artifacts (in relation to the beginning of surface QRS) was dependent on ventricular activation sequence, occurring promptly following intrinsic activation via the right bundle branch (47.1 ± 26.4 ms), later during RV pacing (108.7 ± 22.5 ms) or BiV pacing (109.4 ± 23.1 ms), and significantly later, corresponding to the final part of the QRS, during LV pacing (209.6 ± 40.0 ms, range: 140-340 ms, P < 0.001). Oversensing was significantly more frequent during LV than during RV pacing (35.3% vs 22.5%, P < 0.001). Far-field ELT was observed in six patients.
Oversensing artifacts in the atrial channel are likely caused by depolarization of the basal part of the right ventricle. The novel mechanism of QRS oversensing outside PVARP, caused by a reversed ventricular activation sequence during LV-only pacing, may be important in some CRT patients.
仅左心室（LV）起搏对右心房通道中可能被过度感知的部分心室去极化延迟有显著影响。本研究旨在评估接受心脏再同步治疗（CRT）装置的患者心室激动顺序对QRS波过度感知和远场无休止环起搏器心动过速（ELT）的影响。
本研究检查了102例植入CRT装置的患者。在心脏内电图上检查心房通道中的过度感知伪迹，并在DDD-右心室（RV）、DDD-LV、DDD-双心室（BiV）和AAI起搏模式下确定其相对于QRS波起始的时间。还评估了在心室后心房不应期（PVARP）为250 ms的DDD-LV起搏期间ELT的发生情况。
过度感知伪迹的时间（相对于体表QRS波起始）取决于心室激动顺序，在通过右束支进行固有激动后立即出现（47.1±26.4 ms），在RV起搏期间较晚出现（108.7±22.5 ms）或BiV起搏期间（109.4±23.1 ms），而在LV起搏期间显著更晚，对应于QRS波的最后部分（209.6±40.0 ms，范围：140 - 340 ms，P < 0.001）。LV起搏期间过度感知明显比RV起搏期间更频繁（35.3%对22.5%，P < 0.001）。在6例患者中观察到远场ELT。
心房通道中的过度感知伪迹可能由右心室基底部的去极化引起。在仅LV起搏期间，心室激动顺序逆转导致PVARP外QRS波过度感知的新机制在一些CRT患者中可能很重要。
