Sarrazin Jean-François, Kuehne Michael, Wells Darryl, Chalfoun Nagib, Crawford Thomas, Boonyapisit Warangkna, Good Eric, Chugh Aman, Oral Hakan, Jongnarangsin Krit, Pelosi Frank, Morady Fred, Bogun Frank
Department of Cardiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
Heart Rhythm. 2008 Dec;5(12):1709-14. doi: 10.1016/j.hrthm.2008.08.034. Epub 2008 Sep 3.
Pace mapping is used to identify critical areas for postinfarction ventricular tachycardia (VT). Unexcitable scar during pacing with standard output can identify borders of the reentry circuit. Unexcitable scar is not thought to contain surviving muscle fibers critical to the circuit. Due to current-to-load mismatch or a deep seated isthmus, higher power might be required in order to obtain capture.
The purpose of this study was to evaluate the value of high-output pacing in patients with postinfarction VT.
In a consecutive series of 18 patients (15 men, age 62 +/- 9, EF 0.29 +/- 0.15) with postinfarction VT, a voltage map was obtained and bipolar pace mapping was performed in areas with low voltage (<1.5 mV) at an output of 10 mA and 2 ms pulse width (PW). High-output capture was defined as capture that failed at these settings but succeeded at higher pacing output. The pacing output was increased to 20 mA at 2 ms, and the PW was increased to 10 ms as required to achieve capture.
Seventy-seven VTs were induced. Thirty-nine isthmus sites were identified. Focal areas with high-output capture were observed in 12/18 patients (output: 20 mA; mean PW: 7.3 +/- 3.5 ms). In 9/18 patients, this area was critical for the reentry circuit of 10 clinical VTs (23% of isthmus sites). In one third of patients, isthmus sites were identified only by high-output pacing.
High-output pacing can be helpful in identifying critical areas of postinfarction VT that otherwise may be missed.
起搏标测用于识别心肌梗死后室性心动过速（VT）的关键区域。使用标准输出进行起搏时，不可兴奋瘢痕可识别折返环的边界。人们认为不可兴奋瘢痕不包含对折返环至关重要的存活肌纤维。由于电流与负载不匹配或峡部较深，可能需要更高的能量才能实现夺获。
本研究旨在评估高输出起搏在心肌梗死后室性心动过速患者中的价值。
对连续18例（15例男性，年龄62±9岁，左心室射血分数0.29±0.15）心肌梗死后室性心动过速患者进行研究，获取电压图，并在低电压（<1.5 mV）区域以10 mA输出和2 ms脉宽（PW）进行双极起搏标测。高输出夺获定义为在这些设置下未能夺获但在更高起搏输出时成功夺获。起搏输出增加至20 mA，脉宽根据需要增加至10 ms以实现夺获。
诱发了77次室性心动过速。确定了39个峡部部位。12/18例患者观察到高输出夺获的局灶区域（输出：20 mA；平均脉宽：7.3±3.5 ms）。9/18例患者中，该区域对10次临床室性心动过速的折返环至关重要（占峡部部位的23%）。在三分之一的患者中，仅通过高输出起搏确定峡部部位。
高输出起搏有助于识别心肌梗死后室性心动过速的关键区域，否则这些区域可能会被遗漏。
