Peralta A O, John R M, Venditti F J, Martin D T
Cardiac Electrophysiology Laboratory, Lahey Clinic Medical Center, Burlington, MA 01805, USA.
Pacing Clin Electrophysiol. 1997 Mar;20(3 Pt 1):610-8. doi: 10.1111/j.1540-8159.1997.tb03878.x.
Evaluation of the impact of undersensing on VF detection time and the relationship of undersensing to the programmed shock energy.
Failure to reconfirm an ongoing arrhythmia due to undersensing by a noncommitted ICD might prolong the time to therapy.
We measured initial detection times and redetection times at predischarge and at 2 and 6 months in 29 patients (22 men, mean age 60 years) with a noncommitted nonthoracotomy ICD. Telemetry data and output markers were used to analyze each induction.
Undersensing leading to failure to reconfirm was present in 44 (11.1%) of 398 episodes of sustained VF and prolonged significantly the median initial detection time from 2.3 seconds (25th and 75th percentiles: 2 and 2.6 s, respectively) to 5.45 seconds (4.3 and 7.35 s, P < 0.0001). One episode required external defibrillation after reconfirmation failure occurred during charging; the total detection time prior to shock was 46 seconds. In a subset of 87 episodes with failed first shocks, the initial detection time was 2.3 seconds (2.1 and 2.8 s) and the redetection time 3 seconds (2.5 and 4.77 s, P < 0.0001). The presence of undersensing prolonged the redetection from 2.6 seconds (2.35 and 3.1 s) to 5.4 seconds (4.53 and 7.35 s, P < 0.0001). Undersensing was more prevalent during the redetection period (P = 0.004) and in episodes of sustained VF in which the first shock energy was higher than 15 J (19.7% vs 5.8%, P < 0.0001).
In this automatic defibrillator system, undersensing occurs in 11% of the sustained VF inductions and prolongs detection time significantly. Redetection is longer than initial detection mostly due to the presence of undersensing, the frequency of which is proportional to the programmed energy. The clinical significance of this finding is unknown.
评估感知不足对室颤检测时间的影响以及感知不足与程控电击能量的关系。
非特异性植入式心律转复除颤器（ICD）因感知不足未能再次确认持续性心律失常可能会延长治疗时间。
我们测量了29例（22例男性，平均年龄60岁）非特异性非开胸ICD患者在放电前、2个月和6个月时的初始检测时间和重新检测时间。利用遥测数据和输出标记分析每次诱发情况。
在398次持续性室颤发作中，有44次（11.1%）存在感知不足导致未能再次确认，这显著延长了初始检测时间的中位数，从2.3秒（第25和第75百分位数分别为2秒和2.6秒）延长至5.45秒（4.3秒和7.35秒，P<0.0001）。有1次发作在充电期间再次确认失败后需要体外除颤；电击前的总检测时间为46秒。在首次电击失败的87次发作子集中，初始检测时间为2.3秒（2.1秒和2.8秒），重新检测时间为3秒（2.5秒和4.77秒，P<0.0001）。感知不足的存在将重新检测时间从2.6秒（2.35秒和3.1秒）延长至5.4秒（4.53秒和7.35秒，P<0.0001）。感知不足在重新检测期间更为普遍（P=0.004），并且在首次电击能量高于15J的持续性室颤发作中更常见（19.7%对5.8%，P<0.0001）。
在该自动除颤器系统中，11%的持续性室颤诱发存在感知不足，并显著延长检测时间。重新检测比初始检测时间更长，主要是因为存在感知不足，其频率与程控能量成正比。这一发现的临床意义尚不清楚。
