Ursaru Andreea Maria, Costache Irina Iuliana, Petris Antoniu Octavian, Haba Mihai Stefan Cristian, Mitu Ovidiu, Crisan Adrian, Tesloianu Nicolae Dan
Department of Cardiology, Emergency Clinical Hospital "Sf. Spiridon", 700111 Iași, Romania.
1st Medical Department, "Grigore. T. Popa" University of Medicine and Pharmacy, 700111 Iași, Romania.
Rev Cardiovasc Med. 2022 Apr 2;23(4):124. doi: 10.31083/j.rcm2304124. eCollection 2022 Apr.
Prevention of sudden cardiac death (SCD) early after acute myocardial infarction (AMI) is still a challenge, without clear recommendations in spite of the high incidence of life-threatening ventricular arrhythmias, as implantable cardiac defibrillator (ICD) placement is not indicated in the first 40 days after an AMI; this timing is aleatory and it is owed to fact that the two pivotal studies for evaluation of ICDs in primary prevention, MADIT and MADIT II, excluded the patients within three, respectively four weeks after AMI.
We conducted a retrospective, single-center study that included 77 patients with AMI. All patients were monitored by continuous ECG in the first week after the event. Transthoracic echocardiography was performed at discharge and 40 days after the event. Patients with ejection fraction of 35% or less as assessed by 2D echocardiography 40 days after the MI, which received an ICD for the primary prevention of SCD, were included in the study. The subjects were followed for a median of 38 months, by means of device interrogation and echocardiography.
We divided our patients into two groups: in the first group, with left ventricular ejection fraction (LVEF) under 30% after MI, all patients remained in the reduced ejection fraction heart failure category, with an increase from an initial mean of 18.93 4.99% to a mean of 22.18 4.53% after a period of 40 days; we obtained a positive and statistically significant correlation ( 0.001 and r - 0.547), and all patients presented indication of ICD implant 40 day after MI. In the second group with LVEF between 30% and 35% after MI, the mean LVEF increased from an initial mean of 31.73 1.33% to a mean of 32.33 1.49% after a period of 40 days. A statistically significant correlation ( - 0.02 and r - 0.78) was obtained, although 3 patients presented a LVEF over 35% at 40 days post-MI. Most of the ICD therapies (14.54%) appeared in patients with LVEF 30% and these patients also presented a higher percentage of NSVT at initial ECG monitoring (54% vs. 50%) and NSVT at ICD interrogation (80% vs. 66.7%); statistical significance was not reached - 0.05. The majority of the ICD therapies (11.9% from 13.4%) appeared in patients with NSVT at initial ECG monitoring; also, these presented an increased number of NSVT at ICD interrogation (77.6% vs. 6%) when compared to patients without VT detection at the initial ECG monitoring. Still, statistical significance was not reached - 0.15.
The patients could benefit from ICD implant earlier than stated in the actual guidelines, since there are insufficient data in the literature for the waiting time of 40 days. Correlated with the increased risk of SCD in the first months post myocardial infarction, the present study proves the benefit of early ICD implantation considering that all our patients with a low ejection fraction immediately after infarction remained in the same category and the great majority (96.1%) required the implantation of an ICD after 40 days. Thus, we could avoid exposing our patients at risk of SCD for an unnecessary prolonged period, and choose early ICD implantation.
急性心肌梗死（AMI）后早期预防心源性猝死（SCD）仍是一项挑战，尽管危及生命的室性心律失常发生率很高，但尚无明确的推荐意见，因为在AMI后的前40天内不建议植入植入式心脏除颤器（ICD）；这个时间是随机的，这是由于评估ICD一级预防的两项关键研究MADIT和MADIT II排除了AMI后3周和4周内的患者。
我们进行了一项回顾性单中心研究，纳入77例AMI患者。所有患者在事件发生后的第一周进行连续心电图监测。出院时及事件发生后40天进行经胸超声心动图检查。将心肌梗死后40天通过二维超声心动图评估射血分数为35%或更低且接受ICD进行SCD一级预防的患者纳入研究。通过设备问询和超声心动图对受试者进行了中位时间为38个月的随访。
我们将患者分为两组：在第一组中，心肌梗死后左心室射血分数（LVEF）低于30%，所有患者仍处于射血分数降低的心力衰竭类别，从初始平均18.93±4.99%增加到40天后的平均22.18±4.53%；我们获得了显著的正相关（P<0.001，r = 0.547），并且所有患者在心肌梗死后40天均有植入ICD的指征。在第二组中，心肌梗死后LVEF在30%至35%之间，40天后平均LVEF从初始平均31.73±1.33%增加到平均32.33±1.49%。获得了统计学显著相关性（P = 0.02，r = 0.78），尽管3例患者在心肌梗死后40天时LVEF超过35%。大多数ICD治疗（14.54%）出现在LVEF≤30%的患者中，这些患者在初始心电图监测时非持续性室性心动过速（NSVT）的百分比也更高（54%对50%），在ICD问询时NSVT的百分比也更高（80%对66.7%）；未达到统计学显著性（P>0.05）。大多数ICD治疗（13.4%中的11.9%）出现在初始心电图监测时有NSVT的患者中；同样，与初始心电图监测时未检测到室性心动过速（VT）的患者相比，这些患者在ICD问询时NSVT的数量增加（77.6%对6%）。然而，仍未达到统计学显著性（P>0.15）。
患者可能比现行指南所述更早地从ICD植入中获益，因为文献中关于40天等待时间的数据不足。鉴于心肌梗死后头几个月SCD风险增加，本研究证明了早期植入ICD的益处，因为我们所有梗死后立即射血分数低的患者仍处于同一类别，并且绝大多数（96.1%）在40天后需要植入ICD。因此，我们可以避免让患者在不必要的长时间内面临SCD风险，并选择早期植入ICD。
