Green Ulrika Birgersdotter, Garg Ashok, Al-Kandari Fawzia, Ungab GilAnthony, Tone Linda, Feld Gregory K
Cardiac Electrophysiology Program, Division of Cardiology, Department of Medicine, University of California, San Diego, CA 92103, USA.
J Interv Card Electrophysiol. 2003 Feb;8(1):71-5. doi: 10.1023/a:1022304417889.
Conventionally, the implantable cardioverter-defibrillator (ICD) is tested at implantation by measurement of defibrillation threshold (DFT), which involves repeated induction of ventricular fibrillation (VF). We report our data on successful ICD implantation without VF induction using a modified upper limit of vulnerability (ULV) testing method, compared to standard DFT testing.
Fourteen patients underwent ICD implantation using a modified ULV testing method by delivering a 15 J shock during the vulnerable period on the peak of the T wave, and if VF was not induced 15 J shocks were repeated at -20 and -40 msec before the peak of T wave. Failure to induce VF, indicating a ULV <15 joules (J), suggested a DFT < or =20 J based on previous studies demonstrating a close correlation (+/-5 J) between ULV and DFT. If VF was induced, a 20 J rescue shock was delivered. ICD therapy was then programmed on the basis of ULV testing. All patients underwent pre-discharge DFT testing to confirm adequate DFT.
Using a modified ULV testing method, ICD implantation was completed without induction of VF in 8 patients and only a single episode of VF in 6 patients. The mean number of VF episodes (0.42 +/- 0.5) induced with ULV testing was significantly lower (p <.001) than the number induced during DFT testing (3.9 +/- 0.8). Pre-discharge DFT testing did not alter ICD programming in any patient. During follow-up of 14.85 +/- 12.31 months, three patients had seven episodes of VT/VF, six of whom were converted with the programmed first-shock strength, while one required a second high-energy shock to convert. This patient had a pre-discharge DFT of 10 joules.
Successful ICD implantation can be safely performed with no or fewer episodes of VF induction using a modified ULV testing method.
传统上，植入式心脏复律除颤器（ICD）在植入时通过测量除颤阈值（DFT）进行测试，这需要反复诱发室颤（VF）。我们报告了使用改良的易损性上限（ULV）测试方法成功植入ICD且未诱发VF的数据，并与标准DFT测试进行了比较。
14例患者采用改良的ULV测试方法植入ICD，即在T波峰值的易损期给予15J电击，如果未诱发VF，则在T波峰值前-20和-40毫秒重复给予15J电击。未能诱发VF表明ULV<15焦耳（J），根据先前的研究表明ULV与DFT之间密切相关（±5J），提示DFT≤20J。如果诱发了VF，则给予20J的抢救电击。然后根据ULV测试对ICD治疗进行编程。所有患者均在出院前进行DFT测试以确认DFT是否足够。
使用改良的ULV测试方法，8例患者在未诱发VF的情况下完成了ICD植入，6例患者仅诱发了单次VF发作。ULV测试诱发的VF发作平均次数（0.42±0.5）明显低于DFT测试期间诱发的次数（3.9±0.8）（p<.001）。出院前DFT测试未改变任何患者的ICD编程。在14.85±12.31个月的随访期间，3例患者发生了7次室性心动过速/室颤发作，其中6次通过编程的首次电击强度得以转复，而1例需要第二次高能量电击才能转复。该患者出院前的DFT为10焦耳。
使用改良的ULV测试方法可以安全地成功植入ICD，且诱发VF的次数很少或不诱发VF。
