急性心肌梗塞伴室性心律失常的处理 刘少稳 上 海 市 第 一 人 民 医 院 上海交通大学附属第一人民医院 心内科 1864年建院.

Presentation on theme: "急性心肌梗塞伴室性心律失常的处理 刘少稳 上 海 市 第 一 人 民 医 院 上海交通大学附属第一人民医院 心内科 1864年建院."— Presentation transcript:

1 急性心肌梗塞伴室性心律失常的处理 刘少稳 上 海 市 第 一 人 民 医 院 上海交通大学附属第一人民医院 心内科 1864年建院

2 简 介 VF或持续性VT在STEMI/NSTEMI时的发病率可高达20%
简 介 VF或持续性VT在STEMI/NSTEMI时的发病率可高达20% 急性心肌梗塞时室性心律失常多伴随有严重心肌缺血、泵功能衰竭、电解质（血钾）异常、植物神经功能不平衡、低氧血症和酸碱失衡等 发生心律失常时是否需要治疗主要决定于其对血流动力学的影响程度 心脏猝死的风险主要和心脏病的严重程度有关；VT/VF是心脏猝死的最主要直接原因

3 急性心肌梗塞伴室性心律失常的分类 室性期前收缩 加速性室性自主节律(慢室速) 短阵、非持续性室速 持续性单形性室速 多形性室速 室颤
束支传导阻滞 室内传导阻滞

4 1. 室性早搏 室早在AMI早期常见，各种复杂程度的室早(多形性、连发、R-on-T）预测VT/VF的敏感性、特异性都不强，预防性治疗室早已放弃 抗心肌缺血（-阻滞剂）、补钾、补镁优于抗心律失常 图为急性下壁心梗频发室早二联律。 R-on-T 现象

5 2.加速性室性自主节律(慢室速) 连续3个室早，快于室性逸搏心律(30-40bpm)，<120 bpm。浦氏纤维自律性加强
10％-40％的患者，特别多见于早期再灌注，多数不恶化成VT/VF 原则上不治疗，除非血液动力学不稳定，应用阿托品或心房起搏

6 3. 非持续性室速 连续三个室早，但持续时间<30秒，频率>100次/分 单形性为主
急性缺血12h内Holter检出率可达60%以上 预后意义取决于：梗死面积、心功能状态和NSVT的出现时间

7 NSTE-ACS患者中急性期NSVT的意义
非持续性VT（4到7个心搏）增加1年SCD的风险 --急性心肌梗塞时连续7天Holter监测 SCD, 2.9%; adjusted hazard ratio, 2.3; P<0.001 非持续性VT（>8个心搏）增加1年SCD的风险 SCD, 4.3%; adjusted hazard ratio, 2.8; P=0.001 This effect was independent of baseline characteristics and ejection fraction. 发生在48小时内的NSVT与1年时心脏猝死的发生率无关 Scirica BM, et al. Circulation. 2010;122: Ventricular arrhythmia is a common complication of acute MI, occurring in almost all patients, even before monitoring is possible. It is related to the formation of re-entry circuits at the confluence of the necrotic and viable myocardium. Premature ventricular contractions (PVCs) occur in approximately 90% of patients. The incidence of ventricular fibrillation is approximately 2% to 4%. Although lidocaine has been demonstrated to reduce the rate of primary ventricular fibrillation in patients with MI to some extent, there is no survival benefit and there may be excess mortality. Therefore, it is not recommended that patients receive prophylactic therapy. 33b Amiodarone may be used in patients with MI and frequent PVCs, nonsustained ventricular tachycardia post-MI, or post–defibrillation for ventricular fibrillation. The recommended dosing is a bolus of 150 mg and then administration of 1 mg/min for 6 hours, followed by 0.5 mg/min. When starting this medication for ventricular fibrillation or pulseless ventricular tachycardia (VT), the bolus should be increased to 300 mg (the 150-mg bolus can be repeated in 10 minutes). Ventricular arrhythmias not responsive to amiodarone may be treated with lidocaine (1-mg/kg bolus to a maximum of 100 mg, followed by a 1- to 4-mg/min drip) 44 or procainamide. Polymorphic VT is a rare complication of acute MI and can be treated with amiodarone, lidocaine, or procainamide, or a combination, as described for monomorphic VT. It is usually associated with recurrent ischemia. The importance of ventricular fibrillation in the setting of MI has been re-evaluated in the context of the interaction between severe systolic dysfunction and the potential for sudden cardiac death. Implantable defibrillators have been shown to reduce mortality in patients with an ejection fraction (EF) lower than 30%, regardless of the presence of ventricular dysrhythmia. 45 Supraventricular arrhythmias occur in less than 10% of patients with acute MI. Because patients who develop these arrhythmias tend to have more severe ventricular dysfunction, they have a worse outcome. Although isolated right atrial infarction or small inferior infarcts leading to atrial arrhythmias are not associated with higher mortality rates, the appearance of atrial arrhythmias usually heralds the onset of heart failure in the setting of acute MI. Bradyarrhythmias, including AV block and sinus bradycardia, occur most frequently with inferior MI. Complete AV block occurs in approximately 20% of patients with acute right ventricular infarction. Infranodal conduction disturbances with wide complex ventricular escape rhythms occur most frequently in large anterior MIs and portend a very poor prognosis. Temporary transvenous pacing is indicated in patients who present with asystole, Mobitz type II second-degree AV block, or complete AV block. Consideration for transvenous pacing should be given to patients with bifascicular or trifascicular block in the setting of acute MI. 46 Pacing is not indicated for patient in sinus bradycardia or AV dissociation with a slow sinus rate and a more rapid ventricular escape rhythm as long as the patient is maintaining adequate hemodynamics. If mild symptoms exist, the initial treatment for these rhythm disturbances is IV atropine, 0.5 to 1.0 mg. This may be repeated every 5 minutes, to a maximum dose of 2 mg. 33. Cardiogenic shock complicating acute coronary syndromes. Lancet. 356: 2000; 44. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 346: 2002; 45. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 346: 2002; 46. Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction. J Electrocardiol. 38: 2005;

8 4. 持续性单形性室速 持续30秒，频率>100次/分 （150次/分的VT，血液动力学常相对稳定）
常由折返引起，发生率3-4%左右 常伴心衰、心源性休克、AF，标志大面积心肌梗死 伴持续性室速者，住院死亡率18%以上 持续性室速合并室颤者，住院死亡率40%以上 活存30天，出院一年内死亡率7%以上 无持续性室速者，出院一年内死亡率3%左右 由折返引起，梗死区活存心肌，或疤痕内残留心肌构成折返 ，AMI中发生率3-4%左右 伴心衰，心源性休克、AF，标志大面积梗死 伴SVT者，住院死亡率18%以上 SVT+VF者，住院死亡率40%以上 活存30天，出院一年内死亡率7%以上 无SVT者，出院一年内死亡率3%以上左右

9 AMI患者中持续性室速的意义 急性心肌梗死发病72小时内的持续性单形性VT常伴有较大面积梗死心肌和与之相关的复杂心脏电生理变化
与AF/PVT相比，持续性单形性VT患者： 1）CK-MB升高明显；2）宽QRS（130 ms）的发生率高 (33% vs 8%, P<0.002)；3）血流动力学更不稳定 (Killip分级>I: 58% vs 23%, P<0.04)；4）心肌缺血事件的发生率高(68% vs 16%, P<0.05) Hatzinikolaou-Kotsakou E, et al. J Electrocardiology. 2007;40:72-77 Ventricular arrhythmia is a common complication of acute MI, occurring in almost all patients, even before monitoring is possible. It is related to the formation of re-entry circuits at the confluence of the necrotic and viable myocardium. Premature ventricular contractions (PVCs) occur in approximately 90% of patients. The incidence of ventricular fibrillation is approximately 2% to 4%. Although lidocaine has been demonstrated to reduce the rate of primary ventricular fibrillation in patients with MI to some extent, there is no survival benefit and there may be excess mortality. Therefore, it is not recommended that patients receive prophylactic therapy. 33b Amiodarone may be used in patients with MI and frequent PVCs, nonsustained ventricular tachycardia post-MI, or post–defibrillation for ventricular fibrillation. The recommended dosing is a bolus of 150 mg and then administration of 1 mg/min for 6 hours, followed by 0.5 mg/min. When starting this medication for ventricular fibrillation or pulseless ventricular tachycardia (VT), the bolus should be increased to 300 mg (the 150-mg bolus can be repeated in 10 minutes). Ventricular arrhythmias not responsive to amiodarone may be treated with lidocaine (1-mg/kg bolus to a maximum of 100 mg, followed by a 1- to 4-mg/min drip) 44 or procainamide. Polymorphic VT is a rare complication of acute MI and can be treated with amiodarone, lidocaine, or procainamide, or a combination, as described for monomorphic VT. It is usually associated with recurrent ischemia. The importance of ventricular fibrillation in the setting of MI has been re-evaluated in the context of the interaction between severe systolic dysfunction and the potential for sudden cardiac death. Implantable defibrillators have been shown to reduce mortality in patients with an ejection fraction (EF) lower than 30%, regardless of the presence of ventricular dysrhythmia. 45 Supraventricular arrhythmias occur in less than 10% of patients with acute MI. Because patients who develop these arrhythmias tend to have more severe ventricular dysfunction, they have a worse outcome. Although isolated right atrial infarction or small inferior infarcts leading to atrial arrhythmias are not associated with higher mortality rates, the appearance of atrial arrhythmias usually heralds the onset of heart failure in the setting of acute MI. Bradyarrhythmias, including AV block and sinus bradycardia, occur most frequently with inferior MI. Complete AV block occurs in approximately 20% of patients with acute right ventricular infarction. Infranodal conduction disturbances with wide complex ventricular escape rhythms occur most frequently in large anterior MIs and portend a very poor prognosis. Temporary transvenous pacing is indicated in patients who present with asystole, Mobitz type II second-degree AV block, or complete AV block. Consideration for transvenous pacing should be given to patients with bifascicular or trifascicular block in the setting of acute MI. 46 Pacing is not indicated for patient in sinus bradycardia or AV dissociation with a slow sinus rate and a more rapid ventricular escape rhythm as long as the patient is maintaining adequate hemodynamics. If mild symptoms exist, the initial treatment for these rhythm disturbances is IV atropine, 0.5 to 1.0 mg. This may be repeated every 5 minutes, to a maximum dose of 2 mg. 33. Cardiogenic shock complicating acute coronary syndromes. Lancet. 356: 2000; 44. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 346: 2002; 45. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 346: 2002; 46. Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction. J Electrocardiol. 38: 2005;

10 5. 多形性室速 急性心肌缺血所致，见于AMI起病数小时内 QT间期不延长，偶尔也可延长 持续时间可长可短，易恶化成VF
有效治疗心肌缺血、血运重建(溶栓，PTCA)

11 6. 室颤 心梗后心室颤动的发生率约为3-5％ 相关的危险因素主要有近期吸烟史、左束支传导阻滞及低钾血症
增加住院死亡率，终止AF仍以紧急电除颤为主 β-阻滞剂可能减少心肌梗死后室颤的发作 心电监护上图象可见短阵室速并有频发RonT现象并进一步诱发室颤，但患者血钾2.6mmol/L。电复律后纠正电解质紊乱后未再发室颤。 发生VF后立即采用电除颤，死亡率反低于预防性用药者。AMI后血K +、血Mg 2+分别维持在4.5、2.0mM/L以上，优于预防性抗心律失常药物应用 多项研究表明，心梗后心室颤动的发生率约为5％，其中一半以上的患者发生室颤以前没有任何预兆性心律失常，然而作者认为心梗后室颤的发生率应更高，因为许多心肌梗死的患者还没来得及送至医院就已经发生猝死，而这种猝死的原因多是室颤。与增加心梗后室颤发生率相关的因素主要有近期吸烟史、左束支传导阻滞及低钾血症。前壁心梗合并室颤患者的远期预后要劣于后壁心梗合并室颤的患者。治疗上仍以电除颤为主，β-阻滞剂可能减少心肌梗死后室颤的发作。 原发性VF在十几年以前发生率占AMI住院病人的10%，现已下降 原发性VF 60%发生在起病后4 h内，12 h内占80% 继发性VF常是左心衰或休克的后果，常发生在AMI 48h后 GUSTO-1研究，在溶栓时代后AMI，S-VT发生率3.5%，VF4.1%，VT+VF 2.1% AMI伴SVT住院死亡率18.6%，VT+VF者44% VT或VT+VF存活30天者，出院一年死亡率7%，无VT、VT/VF者为3% 在建立CCU早期，广泛应用利多卡因，认为它降低了MI早期死亡率 现在认为早期应用利多卡因者，没有降低死亡率，治疗预警性心律失常与降低VF发生率无关，因此放弃了预防 AMI后VF的发生率已下降(采用了补K +、Mg 2+、早期用-阻滞剂，重建血运等) 发生VF后立即采用电除颤，死亡率反低于预防性用药者AMI后血K +、血Mg 2+分别维持在4.5、2.0mM/L以上，优于预防性抗心律失常药物应用

12 ACS室性心律失常的处理原则 抗缺血治疗、再灌注治疗等AMI标准治疗
补钾、补镁，使血K+维持在4.14.5 mM/L，血Mg2+维持在2.0 mM/L以上。 早期应用-阻滞剂，可降低VF； 发生VF和血流动力学不稳定的VT应紧急行心脏电复律，之后预防性应用可达龙和-阻滞剂 预防性应用利多卡因可减少VF的发生率，但增加死亡率，可能原因包括心动过缓、停搏的发生率增加 可以看出心肌梗死后室性心律失常在临床十分常见，有些心律失常对预后无不良影响，而有些可导致严重的临床后果，因此心血管医生在临床实践中应仔细区分，识别可能导致严重后果的心律失常，并予以积极处理。 须对心律失常预后作出判断，区别是属于再灌注心率失常还是缺血性心律失常，两者的预后和临床处理不同。 选择AMI合并室性心律失常治疗药物时不能盲目照搬指南，要注重临床治疗个体化。AMI合并心力衰竭及室性心律失常时，多数存在电解质异常（细胞内缺钾、缺镁），当抗缺血及抗心律失常治疗无效时，应注重补充钾盐及镁盐（即使血清钾、镁正常）。

13 急性心肌梗塞伴室性心律失常的处理原则 *I.v. sotalol or other -blockers should not be given if EF is low.

14 急性心肌梗塞伴室性心律失常的处理原则 *I.v. sotalol or other -blockers should not be given if EF is low.

15 电复律 适用于血流动力学不稳定的快速心律失常 1）持续性VT，>150次/分，血流动力学不稳定，同 步100焦耳
3）VF ，200360焦耳，非同步 注意事项：患者意识、电极板的放置、血流动力学不稳 定、同步或非同步

16 室速风暴（无休止性室速） 反复发作需进行电复律治疗的室速，可以是单形性或多形性 常伴有交感神经兴奋
明确有无其他诱因（电解质紊乱、药物、心肌缺血等、低血压、低氧血症） 紧急再灌注治疗，可尝试IABP 静脉应用β受体阻滞剂是最有效的治疗方式，可同时静脉应用胺碘酮，必要时镇静 The syndrome of very frequent episodes of VT requiring cardioversion has been termed “VT storm”。 While a definition of greater than 2 episodes in 24 h has been used。 Hemodynamically stable VT lasting hours has been termed “incessant.” The first step in VT storm is to identify and correct inciting factors, commonly including drugs, electrolyte disturbances, and acute myocardial ischemia。 Intravenous beta blockade should be considered for a polymorphic VT storm as it is the single most effective therapy. In acute ischemia, intravenous amiodarone seems more effective than other antiarrhythmic drugs。 Intra-aortic balloon counterpulsation can be tried. Pacing may be useful especially if the tachycardia onset is pause dependent.

17 束支传导阻滞 见于1015％AMI患者，可导 致高度房室传导阻滞、充血 性心力衰竭、心源性休克、室性心律失常及猝死
新发的束支传导阻滞多提示梗死相关血管完全闭塞，是行PCI、完成再灌注治疗的指证（LBBB） 院内死亡率在新发RBBB患者中最高(18.8%)，其次是新发LBBB(13.2%)，陈旧LBBB (10.1%)和RBBB (6.4%)。在35名急性左主干闭塞患者中，26%在入院ECG中有RBBB(多数伴LAH)。 以上是对急性心梗后常见心律失常的描述，可以看出心肌梗死后心律失常在临床十分常见，有些心律失常对预后无不良影响，而有些可导致严重的临床后果，因此心血管医生在临床实践中应仔细区分，识别可能导致严重后果的心律失常，并予以积极处理。 Dissmann R, et al. Prognostic impact of LBBB in the early stable phase after AMI. International J cardiology. 2008;130: Widimsky P, et al. Primary angioplasty in AMI with RBBB. Euro H J. 2012;33:86-95

18 室内传导阻滞 约35％可发生左前分支传导阻滞 约12％可发生左后分支传导阻滞 从解剖上看，左后分支宽大，新发生左后分支阻滞多提示
 约35％可发生左前分支传导阻滞 约12％可发生左后分支传导阻滞 从解剖上看，左后分支宽大，新发生左后分支阻滞多提示 梗死面积大，死亡率高；而左前分支合并右束支传导阻 滞时，也提示梗死面积大，预后不佳。

19 心源性休克患者室性心律失常的处理 及时纠正心肌缺血、低血压、离子紊乱等心律失常发生的诱因 及时终止血流动力学不稳定的室性心动过速
----电复律 药物—可达龙，静脉应用注意低血压；不要应用-阻滞剂 pLVAD（percutaneous left ventricular assist device）：TandenHeart，Impella，ECMO IABP（Intra-Aortic Balloon Pump）-- suppressing ventricular arrhythmias in cardiogenic shock 可能机制：改善冠脉灌注、降低心脏后负荷 Ventricular arrhythmia is a common complication of acute MI, occurring in almost all patients, even before monitoring is possible. It is related to the formation of re-entry circuits at the confluence of the necrotic and viable myocardium. Premature ventricular contractions (PVCs) occur in approximately 90% of patients. The incidence of ventricular fibrillation is approximately 2% to 4%. Although lidocaine has been demonstrated to reduce the rate of primary ventricular fibrillation in patients with MI to some extent, there is no survival benefit and there may be excess mortality. Therefore, it is not recommended that patients receive prophylactic therapy. 33b Amiodarone may be used in patients with MI and frequent PVCs, nonsustained ventricular tachycardia post-MI, or post–defibrillation for ventricular fibrillation. The recommended dosing is a bolus of 150 mg and then administration of 1 mg/min for 6 hours, followed by 0.5 mg/min. When starting this medication for ventricular fibrillation or pulseless ventricular tachycardia (VT), the bolus should be increased to 300 mg (the 150-mg bolus can be repeated in 10 minutes). Ventricular arrhythmias not responsive to amiodarone may be treated with lidocaine (1-mg/kg bolus to a maximum of 100 mg, followed by a 1- to 4-mg/min drip) 44 or procainamide. Polymorphic VT is a rare complication of acute MI and can be treated with amiodarone, lidocaine, or procainamide, or a combination, as described for monomorphic VT. It is usually associated with recurrent ischemia. The importance of ventricular fibrillation in the setting of MI has been re-evaluated in the context of the interaction between severe systolic dysfunction and the potential for sudden cardiac death. Implantable defibrillators have been shown to reduce mortality in patients with an ejection fraction (EF) lower than 30%, regardless of the presence of ventricular dysrhythmia. 45 Supraventricular arrhythmias occur in less than 10% of patients with acute MI. Because patients who develop these arrhythmias tend to have more severe ventricular dysfunction, they have a worse outcome. Although isolated right atrial infarction or small inferior infarcts leading to atrial arrhythmias are not associated with higher mortality rates, the appearance of atrial arrhythmias usually heralds the onset of heart failure in the setting of acute MI. Bradyarrhythmias, including AV block and sinus bradycardia, occur most frequently with inferior MI. Complete AV block occurs in approximately 20% of patients with acute right ventricular infarction. Infranodal conduction disturbances with wide complex ventricular escape rhythms occur most frequently in large anterior MIs and portend a very poor prognosis. Temporary transvenous pacing is indicated in patients who present with asystole, Mobitz type II second-degree AV block, or complete AV block. Consideration for transvenous pacing should be given to patients with bifascicular or trifascicular block in the setting of acute MI. 46 Pacing is not indicated for patient in sinus bradycardia or AV dissociation with a slow sinus rate and a more rapid ventricular escape rhythm as long as the patient is maintaining adequate hemodynamics. If mild symptoms exist, the initial treatment for these rhythm disturbances is IV atropine, 0.5 to 1.0 mg. This may be repeated every 5 minutes, to a maximum dose of 2 mg. 33. Cardiogenic shock complicating acute coronary syndromes. Lancet. 356: 2000; 44. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 346: 2002; 45. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 346: 2002; 46. Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction. J Electrocardiol. 38: 2005;

20 非抗心律失常药物对急性心肌梗塞室性心律失常的影响
在急性心梗患者中，早期(<48h)发生VF/VT者，30天的死亡率增高(22% vs 5%, P < 0.001)。基础状态下已应用ACEI/ARB者，早期VF/VT的发生率低(odds ratio 0.65, P = 0.008)；即使发生早期VF/VT，其30天的死亡率也低 (17.7% vs 24.2%, P = 0.04). Askari AT, et al. Insights from GUSTO V. Am Heart J. 2009;158: 在急性冠脉综合征患者中，早期、大量应用他汀（60 mg st，40 mg/day atorvastatin vs 10 mg）可明显降低室早和NSVT He XZ, et al. Cardiology Journal. 2010;17: Ventricular arrhythmia is a common complication of acute MI, occurring in almost all patients, even before monitoring is possible. It is related to the formation of re-entry circuits at the confluence of the necrotic and viable myocardium. Premature ventricular contractions (PVCs) occur in approximately 90% of patients. The incidence of ventricular fibrillation is approximately 2% to 4%. Although lidocaine has been demonstrated to reduce the rate of primary ventricular fibrillation in patients with MI to some extent, there is no survival benefit and there may be excess mortality. Therefore, it is not recommended that patients receive prophylactic therapy. 33b Amiodarone may be used in patients with MI and frequent PVCs, nonsustained ventricular tachycardia post-MI, or post–defibrillation for ventricular fibrillation. The recommended dosing is a bolus of 150 mg and then administration of 1 mg/min for 6 hours, followed by 0.5 mg/min. When starting this medication for ventricular fibrillation or pulseless ventricular tachycardia (VT), the bolus should be increased to 300 mg (the 150-mg bolus can be repeated in 10 minutes). Ventricular arrhythmias not responsive to amiodarone may be treated with lidocaine (1-mg/kg bolus to a maximum of 100 mg, followed by a 1- to 4-mg/min drip) 44 or procainamide. Polymorphic VT is a rare complication of acute MI and can be treated with amiodarone, lidocaine, or procainamide, or a combination, as described for monomorphic VT. It is usually associated with recurrent ischemia. The importance of ventricular fibrillation in the setting of MI has been re-evaluated in the context of the interaction between severe systolic dysfunction and the potential for sudden cardiac death. Implantable defibrillators have been shown to reduce mortality in patients with an ejection fraction (EF) lower than 30%, regardless of the presence of ventricular dysrhythmia. 45 Supraventricular arrhythmias occur in less than 10% of patients with acute MI. Because patients who develop these arrhythmias tend to have more severe ventricular dysfunction, they have a worse outcome. Although isolated right atrial infarction or small inferior infarcts leading to atrial arrhythmias are not associated with higher mortality rates, the appearance of atrial arrhythmias usually heralds the onset of heart failure in the setting of acute MI. Bradyarrhythmias, including AV block and sinus bradycardia, occur most frequently with inferior MI. Complete AV block occurs in approximately 20% of patients with acute right ventricular infarction. Infranodal conduction disturbances with wide complex ventricular escape rhythms occur most frequently in large anterior MIs and portend a very poor prognosis. Temporary transvenous pacing is indicated in patients who present with asystole, Mobitz type II second-degree AV block, or complete AV block. Consideration for transvenous pacing should be given to patients with bifascicular or trifascicular block in the setting of acute MI. 46 Pacing is not indicated for patient in sinus bradycardia or AV dissociation with a slow sinus rate and a more rapid ventricular escape rhythm as long as the patient is maintaining adequate hemodynamics. If mild symptoms exist, the initial treatment for these rhythm disturbances is IV atropine, 0.5 to 1.0 mg. This may be repeated every 5 minutes, to a maximum dose of 2 mg. 33. Cardiogenic shock complicating acute coronary syndromes. Lancet. 356: 2000; 44. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 346: 2002; 45. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 346: 2002; 46. Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction. J Electrocardiol. 38: 2005;

21 急性心肌梗塞伴室性心律失常的处理 判定心律失常类型、评价其对预后的影响 1）再灌注心律失常还是缺血性心律失常？ 2）血流动力学是否稳定？
3）持续性或阵发性？心功能状态？ 4）有无电解质紊乱？ 治疗：CCU（心电、血流动力学和生命体征监护）、 电复律、合理应用抗心律失常药物、血运重建 Ventricular arrhythmia is a common complication of acute MI, occurring in almost all patients, even before monitoring is possible. It is related to the formation of re-entry circuits at the confluence of the necrotic and viable myocardium. Premature ventricular contractions (PVCs) occur in approximately 90% of patients. The incidence of ventricular fibrillation is approximately 2% to 4%. Although lidocaine has been demonstrated to reduce the rate of primary ventricular fibrillation in patients with MI to some extent, there is no survival benefit and there may be excess mortality. Therefore, it is not recommended that patients receive prophylactic therapy. 33b Amiodarone may be used in patients with MI and frequent PVCs, nonsustained ventricular tachycardia post-MI, or post–defibrillation for ventricular fibrillation. The recommended dosing is a bolus of 150 mg and then administration of 1 mg/min for 6 hours, followed by 0.5 mg/min. When starting this medication for ventricular fibrillation or pulseless ventricular tachycardia (VT), the bolus should be increased to 300 mg (the 150-mg bolus can be repeated in 10 minutes). Ventricular arrhythmias not responsive to amiodarone may be treated with lidocaine (1-mg/kg bolus to a maximum of 100 mg, followed by a 1- to 4-mg/min drip) 44 or procainamide. Polymorphic VT is a rare complication of acute MI and can be treated with amiodarone, lidocaine, or procainamide, or a combination, as described for monomorphic VT. It is usually associated with recurrent ischemia. The importance of ventricular fibrillation in the setting of MI has been re-evaluated in the context of the interaction between severe systolic dysfunction and the potential for sudden cardiac death. Implantable defibrillators have been shown to reduce mortality in patients with an ejection fraction (EF) lower than 30%, regardless of the presence of ventricular dysrhythmia. 45 Supraventricular arrhythmias occur in less than 10% of patients with acute MI. Because patients who develop these arrhythmias tend to have more severe ventricular dysfunction, they have a worse outcome. Although isolated right atrial infarction or small inferior infarcts leading to atrial arrhythmias are not associated with higher mortality rates, the appearance of atrial arrhythmias usually heralds the onset of heart failure in the setting of acute MI. Bradyarrhythmias, including AV block and sinus bradycardia, occur most frequently with inferior MI. Complete AV block occurs in approximately 20% of patients with acute right ventricular infarction. Infranodal conduction disturbances with wide complex ventricular escape rhythms occur most frequently in large anterior MIs and portend a very poor prognosis. Temporary transvenous pacing is indicated in patients who present with asystole, Mobitz type II second-degree AV block, or complete AV block. Consideration for transvenous pacing should be given to patients with bifascicular or trifascicular block in the setting of acute MI. 46 Pacing is not indicated for patient in sinus bradycardia or AV dissociation with a slow sinus rate and a more rapid ventricular escape rhythm as long as the patient is maintaining adequate hemodynamics. If mild symptoms exist, the initial treatment for these rhythm disturbances is IV atropine, 0.5 to 1.0 mg. This may be repeated every 5 minutes, to a maximum dose of 2 mg. 33. Cardiogenic shock complicating acute coronary syndromes. Lancet. 356: 2000; 44. Amiodarone as compared with lidocaine for shock-resistant ventricular fibrillation. N Engl J Med. 346: 2002; 45. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med. 346: 2002; 46. Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction. J Electrocardiol. 38: 2005;