Myocardial infarction with unusual presentation of otalgia: a case report

A rare case of a patient with unusual symptoms of earache and sore throat for cardiac ischemia is presented. A diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) was made based on initial elevation of troponin and an abnormal electrocardiograph (ECG). Percutaneous coronary intervention (PCI) performed with stent placement in the occluded coronary vessel was followed by a decrease in troponin level and complete resolution of the ear and throat pain and patient recovery from cardiac ischemia.     

Acute coronary syndrome and myocardial infarct--new definitions

Until recently a general consensus existed for the clinical entity diagnosed as myocardial infarction using the world health organisation (WHO) definition. According to the WHO definition myocardial infarction was defined by a combination of two of three typical characteristics: typical symptoms, rise of cardiac enzymes (CK, CK-MB), and a typical ECG pattern involving the development of Q waves. New insights into the development of acute myocardial infarction, the superiority of the biochemical characteristics of cardiac troponin assays over CK and CK-MB measurements in blood, and new therapeutic concepts made a new definition of myocardial infarction, e.g. of the acute myocardial infarction, necessary. Timing of the diagnosis of myocardial necrosis is of outmost importance relative to the time of observation (acute, evolving, healing, healed MI), as is the classification of the extent of myocardial damage (microscopic, small, medium or large). The term "acute coronary syndrome" (ACS) has been established as a working diagnosis for choosing the appropriate therapeutic strategy. In patients with ACS and ST elevation ischemia (STEMI ACS, true posterior ischemia inclusive) as well as in patients with presumably new LBBB, immediate reperfusion therapy should be performed (primary PTCA or thrombolytic therapy), whereas in patients with ECG changes other than ST elevation or new LBBB (NSTEMIACS) additional antiplatlet therapy on top of aspirin and heparin is indicated. In contrast to the acute phase of infarction when troponin in blood often is not detectable yet, the diagnosis of definitive myocardial infarction is based primarily on troponin elevation. Hard criteria for established infarction are the development of pathologic Q waves or healing or healed myocardial necrosis in pathology; troponin may be normal then, depending of time relapsed.     

老年急性ST段抬高型心肌梗死患者经皮冠状动脉介入治疗术后运动恐惧现状及影响因素分析

目的：调查老年急性ST段抬高型心肌梗死患者经皮冠状动脉介入治疗（PCI）术后运动恐惧的现状,并分析运动恐惧的影响因素。方法：以心脏监护室157例急性ST段抬高型心肌梗死PCI术后老年患者作为研究对象,采用运动恐惧量表、自我感受负担量表、简易应对方式量表进行问卷调查。结果：老年急性ST段抬高型心肌梗死PCI术后患者运动恐惧评分为（39.52±8.62）分,52.5%的患者存在运动恐惧,运动恐惧主要受性别、教育水平、家庭月收入、消极应对、自我感受负担的影响;自我感受负担总分在消极应对和运动恐惧总分之间起部分中介作用。结论：老年急性ST段抬高型心肌梗死患者PCI术后患者运动恐惧发生率高,医护人员应关注其影响因素,通过降低患者自我感受负担,鼓励患者采取积极的应对方式,进行心脏康复训练,预防运动恐惧的发生。     

Diagnosis of acute coronary syndrome

The term "acute coronary syndrome" encompasses a range of thrombotic coronary artery diseases, including unstable angina and both ST-segment elevation and non-ST-segment elevation myocardial infarction. Diagnosis requires an electrocardiogram and a careful review for signs and symptoms of cardiac ischemia. In acute coronary syndrome, common electrocardiographic abnormalities include T-wave tenting or inversion, ST-segment elevation or depression (including J-point elevation in multiple leads), and pathologic Q waves. Risk stratification allows appropriate referral of patients to a chest pain center or emergency department, where cardiac enzyme levels can be assessed. Most high-risk patients should be hospitalized. Intermediate-risk patients should undergo a structured evaluation, often in a chest pain unit. Many low-risk patients can be discharged with appropriate follow-up. Troponin T or I generally is the most sensitive determinant of acute coronary syndrome, although the MB isoenzyme of creatine kinase also is used. Early markers of acute ischemia include myoglobin and creatine kinase-MB subforms (or isoforms), when available. In the future, advanced diagnostic modalities, such as myocardial perfusion imaging, may have a role in reducing unnecessary hospitalizations.     

可控性心肌缺血动物模型的制作

目的：建立小型猪可控性心肌缺血的动物模型。方法：健康成年小型猪10只，开胸安置自制水囊缩窄器．建立钝缘支可控性缺血的动物模型。术后行缺血心电图试验、冠脉造影、微球技术检测缺血区心肌水囊加压前后CCBF以及靶血管支配区心肌HE染色观察。结果：制作成功的8其小型猪在水囊加压后均可出现明显的缺血性心电图表现．同时钝缘支下游显影延迟、稀疏．钝缘支近乎完全闭塞，水囊压力撤除后心电图迅速恢复正常，钝缘支远端灌注恢复到水囊加压前状态。水囊加压前后靶血管支配区域CCBF明娩减少（P〈0．05）。HE染色无心肌梗死表现。结论：采用该自制水囊缩窄器可以成功制作可控性心肌缺血动物模型。     

Absence of severe exercise-induced ischemia does not identify low-risk patients with three-vessel coronary artery disease.

The purpose of this study was to determine the prognosis of medically treated patients with three-vessel coronary artery disease and normal left ventricular function who do not have severe ischemia on exercise radionuclide angiography. The absence of severe ischemia was defined prospectively (in accordance with previously published criteria) as the presence of at least one of the following: (1) workload more than 600 kg-m/min, (2) ST-segment depression of less than 1 mm, or (3) unchanged or increased left ventricular ejection fraction during exercise. Of 42 patients (33% in functional class III or IV) followed up for a median duration of 53 months (range, 1 to 84 months), 22 had initial cardiac events during follow-up, including 6 cardiac deaths, 5 nonfatal myocardial infarctions, and 11 late (a median of 29 months after the exercise study) coronary revascularization procedures. At 4 years of follow-up, the overall survival was 83%. Survival free of cardiac death or myocardial infarction was 77%, and survival free of all cardiac events was 59%. Even in the absence of severe exercise-induced ischemia, medically treated patients with three-vessel coronary artery disease and normal left ventricular function still have a poor long-term outcome.     

Sildenafil-associated coronary thrombosis in a patient with angiographically normal coronary arteries: a case report with review of literature

Sildenafil is widely used as a primary pharmacological treatment of erectile dysfunction in men with and without underlying cardiovascular disease. Although initial reports of adverse cardiac events were reported soon after Food and Drug Administration approval of this agent, a large body of data suggests that sildenafil does not significantly increase the risk of nonfatal myocardial infarction, stroke, or cardiovascular deaths in patients with preexisting ischemic heart disease. We report the case of a 66-year-old man who developed thrombotic occlusion of the left anterior descending artery and presented with acute myocardial infarction after the use of sildenafil. The patient had presented with chest pain syndrome and borderline elevation of serum troponin I levels 1 week before sildenafil use, and a coronary angiogram had demonstrated normal coronary arteries. This case emphasizes the potential of precipitating coronary thrombosis in patients with unstable plaque after sildenafil use, even in patients with angiographically normal coronary arteries.     

Prognostic value of serum concentration of heart-type fatty acid-binding protein relative to cardiac troponin T on admission in the early hours of acute coronary syndrome

BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is proposed as an early biomarker for acute myocardial infarction (AMI), but its prognostic value is unclear in acute coronary syndrome (ACS). We evaluated the prognostic value of the H-FABP concentration relative to cardiac troponin T (cTnT) in the early hours of ACS. METHODS: Serum concentrations of H-FABP and cTnT were measured on admission in 328 consecutive patients hospitalized for ACS within 6 h after the onset of chest pain [AMI, 241 (73.5%) patients; ST-segment elevation myocardial infarction, 154 (47.0%) patients; and emergent coronary angiography within 24 h after admission, 287 (87.5%) patients]. Cardiac events, which were defined as cardiac death or subsequent nonfatal AMI, were monitored for 6 months after admission. RESULTS: During the 6-month follow-up period, there were 25 cardiac events, including 15 cardiac deaths and 10 subsequent nonfatal AMIs. Stepwise multivariate analyses including clinical, electrocardiographic, and biochemical variables revealed that increased H-FABP (above the median of 9.8 microg/L), but not increased cTnT (above the median of 0.02 microg/L), was independently associated with cardiac events in all patients [relative risk (RR) = 8.96; P = 0.0004], the subgroup of patients with ST-segment elevation myocardial infarction (RR = 11.3; P = 0.02), and the subgroup of patients with unstable angina and non-ST-segment elevation myocardial infarction (RR = 8.31; P = 0.007). The area under the ROC curve was higher for H-FABP than for cTnT (0.711 vs 0.578; P = 0.08), suggesting that H-FABP concentrations have a greater predictive capacity for cardiac events than cTnT. CONCLUSION: Serum H-FABP is a potential independent predictor of cardiac events within 6 months of patient admission and may provide prognostic information superior to cTnT in the early hours of ACS.     

Value of a single troponin T at the time of presentation as compared to serial CK-MB determinations in patients with suspected myocardial ischemia

BACKGROUND: Prior studies with cardiac markers have focused predominantly on subjects presenting to the emergency department with chest pain or unstable angina, and have relied on serial markers for the diagnosis of acute myocardial infarction. We evaluated the diagnostic utility of a single cardiac troponin T (cTnT) determination at the time of presentation as compared to serial creatine kinase (CK) MB determinations in a broad spectrum of patients with suspected myocardial ischemia. METHODS: A total of 267 consecutive patients presenting to the emergency department with suspected myocardial ischemia had a single, blinded cTnT determination drawn at the time of presentation to the emergency department in addition to routine serial electrocardiographic and CK-MB determinations. RESULTS: The specificity (93.7% vs. 87.1%; p<0.05) and positive predictive value (80.0% vs. 69.4%; p<0.05) of a single cTnT determination were superior to that of serial CK-MB determinations without compromising sensitivity. Forty-six percent of patients with confirmed myocardial infarction and an abnormal cTnT at presentation had a normal initial CK-MB determination. Conversely, 20% of patients without acute coronary syndromes had an abnormal CK-MB determination in the setting of a normal cTnT. The initial cTnT was abnormal in all patients with confirmed myocardial infarction and a symptom duration of at least 3.5 h. CONCLUSIONS: In a heterogeneous population of patients with suspected myocardial ischemia, the initial cTnT determination drawn at the time of presentation is a powerful diagnostic tool that, when used in context with symptom duration, allows for more rapid and accurate triage of patients than serial CK-MB determinations.     

Vasospasm-lnduced Myocardial Infarction With Sumatriptan

Sumatriptan, a 5-hydroxytryptamine¹ (5-HT₁) receptor agonist is an effective abortive agent for migraine headaches. A common side effect in 3% to 7.9% of patients is chest pain. Although most cases of chest pain are not thought to be of cardiac origin, its mechanism is not entirely understood. Rare examples of electrocardiogram changes consistent with transient ischemia have been reported. Isolated instances of angina, arrhythmia, myocardial infarction, and death have been temporally associated with sumatriptan administration. In most cases, it is unclear whether underlying cardiovascular disease existed or contributed to this adverse event. We report the history of a 56-year-old female patient with migraine who experienced myocardial infarction shortly after using sumatriptan, despite having had a normal cardiovascular evaluation. As she had a normal cardiac catheterization after the event, we find it probable that sumatriptan induced coronary vasospasm and myocardial infarction.     

The initial electrocardiogram in patients seen by a mobile coronary care unit

The advent of thrombolytic therapy for patients with suspected acute myocardial infarction has highlighted the importance of the initial electrocardiogram (ECG) in decision making. Thus we analysed the initial ECGs of 94 consecutive cases with suspected myocardial infarction who were seen within six hours after the onset of chest pain by a mobile coronary care unit. The study included 91 patients (three patients admitted twice) (61 male), aged 27-83 years (mean 60.5). Median time from onset of chest pain to arrival of the mobile coronary care unit was 75 minutes (range 15-345), and mean mobile coronary care unit response time was 12.3 +/- 7 (SD) minutes (range 5-45). The majority of cases (65 of 94, 69.1 per cent) were seen within two hours of the onset of symptoms. A final diagnosis of myocardial infarction was made in 48 of 94 (51.1 per cent) cases; 38 had unstable angina and eight other diagnoses. Of the 48 with myocardial infarction the initial ECG showed ST segment elevation in 37, ST depression and or T wave inversion in six, Q waves only in three and left bundle branch block in two. No patient with an initially normal ECG had a myocardial infarction. Thrombolytic therapy was given out of hospital to 33 of 38 patients with ST segment elevation. In seven patients with ST elevation (median delay time to intensive care 60 minutes), rapid resolution of ST segment elevation occurred following thrombolytic therapy and there was no significant elevation of cardiac enzymes, suggesting that the infarct had been aborted.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute Coronary Syndromes: Diagnosis and Management, Part I

The term acute coronary syndrome (ACS) refers to any group of clinical symptoms compatible with acute myocardial ischemia and includes unstable angina (UA), non—ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). These high-risk manifestations of coronary atherosclerosis are important causes of the use of emergency medical care and hospitalization in the United States. A quick but thorough assessment of the patient''s history and findings on physical examination, electrocardiography, radiologic studies, and cardiac biomarker tests permit accurate diagnosis and aid in early risk stratification, which is essential for guiding treatment. High-risk patients with UA/NSTEMI are often treated with an early invasive strategy involving cardiac catheterization and prompt revascularization of viable myocardium at risk. Clinical outcomes can be optimized by revascularization coupled with aggressive medical therapy that includes anti-ischemic, antiplatelet, anticoagulant, and lipid-lowering drugs. Evidence-based guidelines provide recommendations for the management of ACS; however, therapeutic approaches to the management of ACS continue to evolve at a rapid pace driven by a multitude of large-scale randomized controlled trials. Thus, clinicians are frequently faced with the problem of determining which drug or therapeutic strategy will achieve the best results. This article summarizes the evidence and provides the clinician with the latest information about the pathophysiology, clinical presentation, and risk stratification of ACS and the management of UA/NSTEMI.ACC = American College of Cardiology; ACE = angiotensin-converting enzyme; ACS = acute coronary syndrome; ADP = adenosine diphosphate; AHA = American Heart Association; BNP = B-type natriuretic peptide; CABG = coronary artery bypass grafting; CAD = coronary artery disease; CHF = congestive heart failure; CI = confidence interval; CK-MB = muscle and brain fraction of creatine kinase; CRP = C-reactive protein; CURE = Clopidogrel in Unstable Angina to Prevent Recurrent Events; ECG = electrocardiography; ED = emergency department; GP = glycoprotein; HR = hazard ratio; IV = intravenous; LDL = low-density lipoprotein; LMWH = low—molecular-weight heparin; LV = left ventricular; MI = myocardial infarction; NSTEMI = non—ST-segment elevation MI; PCI = percutaneous coronary intervention; STEMI = ST-segment elevation MI; TIMI = Thrombolysis in Myocardial Infarction; UA = unstable angina; UFH = unfractionated heparinThe term acute coronary syndrome (ACS) refers to any group of clinical symptoms compatible with acute myocardial ischemia and covers the spectrum of clinical conditions ranging from unstable angina (UA) to non—ST-segment elevation myocardial infarction (NSTEMI) to ST-segment elevation myocardial infarction (STEMI). Unstable angina and NSTEMI are closely related conditions: their pathophysiologic origins and clinical presentations are similar, but they differ in severity. A diagnosis of NSTEMI can be made when the ischemia is sufficiently severe to cause myocardial damage that results in the release of a biomarker of myocardial necrosis into the circulation (cardiac-specific troponins T or I, or muscle and brain fraction of creatine kinase [CK-MB]). In contrast, the patient is considered to have experienced UA if no such biomarker can be detected in the bloodstream hours after the initial onset of ischemic chest pain. Unstable angina exhibits 1 or more of 3 principal presentations: (1) rest angina (usually lasting >20 minutes), (2) new-onset (<2 months previously) severe angina, and (3) a crescendo pattern of occurrence (increasing in intensity, duration, frequency, or any combination of these factors). Each year in the United States, approximately 1.36 million hospitalizations are required for ACS (listed either as a primary or a secondary discharge diagnosis), of which 0.81 million are for myocardial infarction (MI) and the remainder are for UA. Roughly two-thirds of patients with MI have NSTEMI; the rest have STEMI.¹     

Delayed-contrast enhancement cardioresonance in transient left ventricular apical ballooning

Transient left ventricular apical ballooning (TAB) is a condition that mimics acute coronary syndrome typically without coronary angiographic stenosis. Patients present with typical chest pain, ECG changes suggesting ischemia, and a slight elevation of myocardial injury markers such as Creatine kinase and Troponines. Ballooning during ventricular systole of the cardiac apex is a characteristic feature of this entity. It is transient and it usually resolves after a few days together with normalization of ECG changes. Initially, apical dyskinesis can be diagnosed by any cardiac imaging technique that allows myocardial wall motion assessment. Recent advances in cardiovascular magnetic resonance imaging (CMR) have made this technique to become the gold-standard method to assess myocardial infarction. CMR provides an excellent and reproducible assessment of segmental wall motion abnormalities and, more importantly, it allows an accurate depiction of myocardial necrotic area by means of delayed contrast-enhancement method. Therefore, it may be particularly useful in the assessment of TAB by demonstrating segmental dysfunction in the absence of myocardial irreversible damage. We report three cases of TAB in which contrast- enhanced CMR emerged as an excellent diagnostic tool.     

Biochemical markers in acute coronary syndrome

Owing to their higher risk for cardiac death or ischemic complications, patients with acute coronary syndrome (ACS) must be identified from other causes of chest pain. Patients with acute coronary syndrome are divided into categories based on their electrocardiogram; those with new ST-segment elevation and those who present with ST-segment depression. The subgroups of patients with ST-segment elevation are candidates for immediate reperfusion, while fibrinolysis appears harmful for those with non-ST elevation myocardial infarction. There is increasing evidence to encourage appropriate risk stratification before deciding on a management strategy (invasive or conservative) for each patient. The TIMI, GRACE or PURSUIT risk models are recommended as useful for decisions regarding therapeutic options. Cardiac biomarkers are useful additions to these clinical tools to correctly risk stratify ACS patients. Cardiac troponin is the biomarker of choice to detect myocardial necrosis and is central to the universal definition of myocardial infarction. The introduction of troponin assays with a lower limit of detection will allow for earlier diagnosis of patients who present with chest pain. Analytical and clinical validations of these new assays are currently in progress. The question is whether the lower detection limit of the troponin assays will be able to indicate myocardial ischemia in the absence of myocardial necrosis. Previous to the development of ultrasensitive cardiac troponin assays free fatty acids unbound to albumin and ischemia modified albumin were proposed as biochemical markers of ischemia. Advances in our knowledge of the pathogenesis of acute coronary thrombosis have stimulated the development of new biomarkers. Markers of left ventricular performance (N-terminal pro-brain natriuretic peptide) and inflammation (e.g. C-reactive protein) are generally recognized as risk indicators. Studies suggest that using a number of biomarkers clinicians can risk stratify patients over a broad range of short and long term cardiac events. Nevertheless, it is still under debate as to which biomarker combination is best preferred for risk prediction. This review will focus on recent practice guidelines for the management of patients with ACS as well as current advances in cardiac biomarkers, their integration into clinical care and their diagnostic, prognostic and therapeutic utility.     

Acute ST Elevation Myocardial Infarction Due to Allergic Reaction,Kounis Syndrome

Kounis syndrome is defined by the occurrence of an acute coronary syndrome (ACS) in the setting of an allergic, hypersensitivity or anaphylactic condition. Degranulation of mast cells and platelet activation leading to the release of multiple inflammatory mediators are thought to make the arterial circulation susceptible to acute cardiac events. It is an often underdiagnosed entity in the emergency setting, due to lack of awareness among emergency providers. Identifying Kounis syndrome is critical, since managing ACS differs from that of a classical acute myocardial infarction. We present the case of a 72-year old male patient with a history of stable coronary disease who presented to the emergency department with a diffuse pruritic rash and chest pain. Electrocardiogram showed ST elevation myocardial infarction. Urgent coronary angiography revealed total occlusion of the mid left anterior descending coronary artery which was treated with a drug eluting stent with an excellent outcome. The pruritic rash responded to treatment with intravenous corticosteroids and antihistamines; No allergens were identified. The patient’s symptoms resolved and he had an uneventful hospitalization.The diagnosis of Kounis syndrome can complicate the management of acute allergic reactions. Special precautions should be taken by emergency physicians with regards to the administration of beta blockers, morphine and vasodilators, which may be detrimental in this setting.     

Unbound free fatty acids and heart-type fatty acid-binding protein: diagnostic assays and clinical applications

BACKGROUND: A biomarker that reliably detects myocardial ischemia in the absence of necrosis would be useful for initial identification of unstable angina patients and for differentiating patients with chest pain of an etiology other than coronary ischemia, and could provide clinical utility complementary to that of cardiac troponins, the established markers of necrosis. Unbound free fatty acids (FFA(u)) and their intracellular binding protein, heart-type fatty acid-binding protein (H-FABP), have been suggested to have clinical utility as indicators of cardiac ischemia and necrosis, respectively. METHODS: We examined results of clinical assessments of FFA(u) and H-FABP as biomarkers of cardiac ischemia and necrosis. Data published on FFA(u) and H-FABP over the past 30 years were used as the basis for this review. RESULTS: Although little clinical work has been done on FFA(u) since the initial reports, recent studies documented an association between increased serum FFAs and ventricular dysrhythmias and death in patients with acute myocardial infarction (AMI). Recent data suggest that serum FFA(u) concentrations increase well before markers of cardiac necrosis and are sensitive indicators of ischemia in AMI. H-FABP is abundant in cardiac muscle and is presumed to be involved in myocardial lipid homeostasis. Similar to myoglobin, plasma H-FABP increases within 3 h after AMI and returns to reference values within 12-24 h. CONCLUSIONS: FFA(u) may have a potential role in identifying patients with cardiac ischemia. H-FABP is useful for detecting cardiac injury in acute coronary syndromes and predicting recurrent cardiac events in acute coronary syndromes and in congestive heart failure patients. Assays are available for both markers that could facilitate further clinical investigations to assess their possible roles as markers of cardiac ischemia and/or necrosis.     

Expanding the role of percutaneous coronary intervention in patients resuscitated from cardiac arrest

Special attention to post–cardiac arrest management is important to long-term survival and favorable neurological outcome in patients resuscitated from cardiac arrest. The use of emergent percutaneous coronary intervention in resuscitated patients presenting with ST-segment elevation myocardial infarction has long been considered an appropriate approach for coronary revascularization. Recent evidence suggests that other subsets of patients, namely, post–cardiac arrest patients without ST-segment elevation myocardial infarction, may benefit from immediate percutaneous coronary intervention following resuscitation. These findings could eventually have important implications for the care of resuscitated patients, including transportation of resuscitated patients to appropriate cardiac interventional facilities, access to treatment modalities such as therapeutic hypothermia, and coordinated care with cardiac catheterization laboratories.     

心肌肌钙蛋白Ⅰ和肌钙蛋白T对急性缺血性心脏病预后相关性分析

目的探讨心肌肌钙蛋白I(cTnI)和肌钙蛋白T(cTnT)对急性缺血性心脏病转归的影响。方法对就诊的急性缺血性心脏病患者定性测定入院时及距胸痛发作间隔10h的cTnI和定量测定相同时点的cTnT。同时随访患者发病后1、3、6、12个月的疾病转归,以心绞痛、心肌梗死、心力衰竭、心源性猝死为终点评价指标。结果cTnI或cTnT异常患者与正常者相比较,不稳定型心绞痛、心肌梗死、心力衰竭、心源性猝死的发生率具有显著性差异(P<0.01)。cTnI或cTnT异常与终点事件(不稳定型心绞痛、心肌梗死、心力衰竭、心源性心源性猝死)发生率呈正相关。结论cTnI或cTnT对急性心肌梗死,尤其是微小心肌坏死诊断具有高度的敏感性和特异性,并与急性缺血性心脏病的预后密切相关。     

冠心病患者动态心电图监测的研究

目的：研究动态心电图对冠心病患监测的价值。方法：对276例冠心病患进行24—72h的动态心电图监测并与常规心电图结果进行对比分析。结果：动态心电图对冠心病患的心律失常检出率达100％，无症状心肌缺血检出率为26．80％，明显高于常规心电图的检出率(61％及5．80％)。结论：动态心电图能及时发现冠心病患的各种心率失常和无症状心肌缺血，对于预防和防止急性心梗和心源性猝死较常规心电图更可靠。