Electrocardiographic considerations in right ventricular infarction.

Right ventricular infarction frequently occurs in the setting of infarction of the inferior wall of the left ventricle. Although there are several protective mechanisms that may limit the size of the infarction, right ventricular damage can result in right ventricular failure and cardiogenic shock. ECG manifestations of right ventricular infarction can facilitate the early recognition of this syndrome. The standard 12-lead ECG may provide some evidence of infarction of the right ventricle. ST-segment elevation in right precordial leads, however, is far more reliable in establishing a diagnosis. These leads should be recorded immediately if the standard 12-lead ECG reveals an acute inferior wall MI. Continuous ST-segment monitoring may be useful in the early detection of ongoing right ventricular ischemia. ECG markers can aid in the prompt institution of appropriate treatment. It is clear that early recognition of right ventricular infarction can have important diagnostic and therapeutic implications.     

Role of 2-dimensional speckle tracking echocardiography in diagnosis of right ventricular involvement in patients with inferior wall myocardial infarction undergoing primary percutaneous coronary intervention

The International Journal of Cardiovascular Imaging - Diagnosis of right ventricular (RV) infarction in the setting of acute inferior wall myocardial infarction (IWMI) has important prognostic...     

Precordial Steering Wheel: A Fortunate Accident

Background: Myocardial ischemia has been associated with motor vehicle collisions (MVCs). However, we were unable to find reported cases of ST-segment elevation myocardial infarction (STEMI) leading to ventricular tachyarhythmia and subsequent MVC. In such patients, decisions regarding antiplatelet and antithrombotic therapy need to balance the risk of ongoing myocardial ischemia and hemorrhage. Objectives: To describe a case of STEMI and ventricular fibrillation (VF) associated with a head-on MVC, and to describe the management decisions involved in the care of such a patient. Case report: A 47-year-old man presented to the Emergency Department after a single-car head-on collision with a wall at high speed. He had a facial degloving injury as well as right-sided flail chest. An electrocardiogram demonstrated ST-segment elevation in the inferior and anterior leads. Due to the patient's significant traumatic injuries, he underwent a rapid trauma evaluation and was transferred for emergent cardiac catheterization, which demonstrated evidence of plaque rupture in the right coronary artery (RCA). Flow distal to the lesion was preserved, so stent implantation was initially deferred out of concern for hemorrhage secondary to the aggressive antiplatelet and antithrombotic regimen requisite with stent implantation. The patient then went into VF in the cardiac catheterization laboratory, and repeat angiography demonstrated an occluded RCA, and the patient underwent successful stent implantation. Conclusion: The management of STEMI in the setting of trauma is complex. Pharmacologic agents used in STEMI increase the risk of bleeding, and management must balance the risk of prolonged ischemia with the risk of hemorrhage.     

Lead aVL on electrocardiogram: emerging as important lead in early diagnosis of myocardial infarction?

Although a diagnosis of acute myocardial infarction (AMI) that mandates emergency reperfusion therapy requires ST-segment elevation greater than 1 mm in at least 2 contiguous leads, some of the early electrocardiogram (ECG) changes of AMI can be subtle. Any ST-segment depression or T-wave inversion in lead aVL may be implicated in left anterior descending artery lesion or early reciprocal changes of inferior wall myocardial infarction, particularly when the clinical context suggests ischemia. Early recognition of reciprocal changes and serial ECG help initiate early appropriate intervention. Heightened awareness of ST segment and T-wave changes in lead aVL is of paramount importance to quickly identifying life-threatening condition.     

常规十二导联诊断急性下壁心肌梗塞的效果观察

目的：以单纯性下壁心肌梗塞为对照,探讨右室心肌梗塞合并急性下壁心肌梗塞的12导联心电图特征.材料与方法：2010年1月至2013年8月间诊治的22例右室心肌梗塞合并急性下壁心肌梗塞患者列入研究组,同期48例单纯下壁心肌梗塞患者列入对照组,回顾性观察两组患者常规12导联心电图特征,并进行比较分析.结果：ST段抬高幅度比较,研究组Ⅲ＞ⅡI的检出率为90.1％,对照组仅4.2％,研究组明显高于对照组,数据经统计学比较具有极显著差异（P＜0.01）,检验特异性为90.1％;ST段在V2导联中压低幅度和aVF导联中抬高幅度的比值比较,研究组≤0.5的患者比例为81.8％,明显高于对照组的比例4.2％,数据经统计学比较具有极显著差异（P＜0.01）,检验特异性为90％.结论：利用常规12导联心电图诊断急性下壁心肌梗塞是否合并有右室心肌梗塞具有较高的特异性和敏感性,当ST段抬高幅度出现Ⅲ＞ Ⅱ时,或ST段在V2导联中压低幅度和aVF导联中抬高幅度的比值≤0.5时,均提示较大可能性的右室心肌梗塞发生.     

Right ventricular infarction

Right ventricular infarction is present in up to 80% of autopsy specimens following fatal myocardial infarction. The clinical features suggestive of right ventricular infarction such as raised systemic venous pressure, clear lung fields, hypotension and atrio-ventricular nodal disturbances usually occur in association with inferior myocardial infarction, with an incidence of 30–50%. Kussmaul‘s sign of a paradoxical rise in the jugular venous pressure wave on inspiration is both sensitive and specific for right ventricular infarction. A 1mm rise in the V4R ST segment on ECG has a positive predictive value for right ventricular infarction of over 70%, increasing to 90% with the addition of ST elevation in leads VSR and V6R. ECG changes are often transient. Acute management of right ventricular infarction includes fluid loading and inotropic support with dobutamine as necessary, with avoidance of vasodilators and diuretics. Mortality from acute myocardial infarchon is increased by right ventricular infarction, but may be lessened by thrombolytic therapy in eligible patients.     

Augmented Vector Right ST-Segment Elevation: Pearls and Pitfalls

ST-segment elevation myocardial infarction (STEMI) is characterized by ST-segment elevation in at least 2 contiguous leads, chest discomfort, and the release of biomarkers requiring emergent revascularization. In 2013, the American College of Cardiology Foundation/American Heart Association revised STEMI guidelines to include augmented vector right (aVR) ST-segment elevation to be treated as a STEMI equivalent. However, aVR ST-segment elevation with multilead ST depression can occur in presentations other than occlusive myocardial infarctions. The purpose of this clinical feature is to provide a brief review of aVR ST-segment elevation, explore approaches to clinical decision making, and provide tools to support nurse practitioners caring for patients with cardiac issues.     

Discriminating between right coronary artery and circumflex artery occlusion by using a noninvasive 18-lead electrocardiogram.

BACKGROUND: Differentiating occlusion of the circumflex branch of the left coronary artery (also called the circumflex artery) from occlusion of the right coronary artery is often difficult because either may be associated with a pattern of acute inferior myocardial infarction on the electrocardiogram. OBJECTIVES: To determine if an inexpensive 18-lead electrocardiogram can provide useful information in differentiating sites of coronary occlusion. METHODS: Continuous 18-lead electrocardiograms, including standard 12-lead, right ventricular, and posterior leads, were recorded in 38 and 50 subjects undergoing percutaneous coronary interventions in the right coronary artery and the circumflex artery, respectively. RESULTS: ST-segment elevation in the posterior leads was twice as frequent during occlusion of the circumflex artery as during right coronary occlusion (P < .001). ST-segment elevation in the right ventricular leads and inferior leads occurred more often during occlusion of the right coronary artery than during occlusion of the circumflex artery. ST-segment depression in lead aVL is highly suggestive of right coronary occlusion, whereas ST-segment elevation in posterior leads without depression of the ST segment in lead aVL is highly sensitive and specific for occlusion of the circumflex artery. CONCLUSIONS: ST-segment changes in the 18-lead electrocardiogram can be used to differentiate between occlusions of the circumflex artery and occlusions of the right coronary artery. Knowing which vessel is occluded before percutaneous coronary intervention can help in planning the procedure and recognizing when patients are at high risk for disturbances in conduction at the atrioventricular node.     

Prehospital Nitroglycerin Safety in Inferior ST Elevation Myocardial Infarction

Patients with inferior ST elevation myocardial infarction (STEMI), associated with right ventricular infarction, are thought to be at higher risk of developing hypotension when administered nitroglycerin (NTG). However, current basic life support (BLS) protocols do not differentiate location of STEMI prior to NTG administration. We sought to determine if NTG administration is more likely to be associated with hypotension (systolic blood pressure < 90 mmHg) in inferior STEMI compared to non-inferior STEMI. We conducted a retrospective chart review of prehospital patients with chest pain of suspected cardiac origin and computer-interpreted prehospital ECGs indicating “ACUTE MI.” We included all local STEMI cases identified as part of our STEMI registry. Univariate analysis was used to compare differences in proportions of hypotension and drop in systolic blood pressure ≥ 30 mmHg after nitroglycerin administration between patients with inferior wall STEMI and those with STEMI in another region (non-inferior). Multiple variable logistic regression analysis was also used to assess the study outcomes while controlling for various factors. Over a 29-month period, we identified 1,466 STEMI cases. Of those, 821 (56.0%) received NTG. We excluded 16 cases because of missing data. Hypotension occurred post NTG in 38/466 inferior STEMIs and 30/339 non-inferior STEMIs, 8.2% vs. 8.9%, p = 0.73. A drop in systolic blood pressure ≥ 30 mmHg post NTG occurred in 23.4% of inferior STEMIs and 23.9% of non-inferior STEMIs, p = 0.87. Interrater agreement for chart review of the primary outcome was excellent (κ = 0.94). NTG administration to patients with chest pain and inferior STEMI on their computer-interpreted electrocardiogram is not associated with a higher rate of hypotension compared to patients with STEMI in other territories. Computer interpretation of inferior STEMI cannot be used as the sole predictor for patients who may be at higher risk for hypotension following NTG administration.     

急性下壁心肌梗死胸前导联ST段改变的临床意义

目的分析急性下壁心肌梗死伴胸前导联ST段压低的临床意义。方法选择38例急性下壁心肌梗死患者常规心电图及24h动态心电图进行对照分析。结果急性下壁心肌梗死伴胸前导联ST段压低多于不伴胸前导联ST段压低(P<0.01);下壁伴正后壁心肌梗死伴胸前导联ST段压低多于不伴胸前导联ST段压低(P<0.01);下壁伴右心室心肌梗死与胸前导联ST段压低无明显关联(P<0.01);急性下壁心肌梗死伴胸前导联ST段压低者严重室性心律失常与房室传导阻滞的发生率较不伴胸前导联ST段压低者高(P<0.01)。结论急性下壁心肌梗死伴胸前导联ST段压低往往提示梗死范围大或同时存在心肌缺血、冠脉病变广泛、心功能损害较严重,并且严重室性心律失常与房室传导阻滞的发生率明显增高,心肌酶峰值明显增高临床预后较差。     

急性下壁心肌梗死胸前导联ST段压低的临床意义

目的分析急性下壁心肌梗死伴胸前导联ST段压低的临床意义。方法选择84例急性下壁心肌梗死患者常规心电图及24h动态心电图进行对照分析。结果急性下壁心肌梗死伴胸前导联ST段压低多于不伴胸前导联ST段压低（P〈0．01）;下壁伴正后壁心肌梗死伴胸前导联ST段压低多于不伴胸前导联ST段压低（P〈0．01）;下壁伴右心室心肌梗死与胸前导联ST段压低无明显关联（P〈0．01）;急性下壁心肌梗死伴胸前导联ST段压低者严重室性心律失常与房室传导阻滞的发生率较不伴胸前导联ST段压低者高（P〈0．01）。结论急性下壁心肌梗死伴胸前导联ST段压低往往提示梗死范围大或同时存在心肌缺血、冠脉病变广泛、心功能损害较严重,并且严重室性心律失常与房室传导阻滞的发生率明显增高,心肌酶峰值明显增高临床预后较差。     

Survival after left ventricular free wall rupture following acute myocardial infarction by conservative treatment

Left ventricular free wall rupture (LVFWR) is a rare and fatal mechanical complication following an acute myocardial infarction (AMI). Cases of survival after LVFWR due to ST-segment elevation myocardial infarction (STEMI) treated with a conservative treatment strategy are extremely rare. In this case, a 55-year-old male patient with several cardiovascular risk factors presented to the emergency department with symptoms of ongoing chest pain and syncope. The patient's electrocardiogram was in sinus rhythm with ST-elevation on I, aVL, and V4–6 leads. His myoglobin and troponin I levels were elevated. Due to the unstable hemodynamic state of the patient, bedside echocardiography was performed. The echocardiography indicated LVFWR after AMI. Pericardiocentesis was used to restore a satisfactory hemodynamic state in the patient. Following the initial treatment, the patient opted for a conservative treatment strategy and was uneventfully discharged after 19 days.     

Evaluation of right atrial function by two-dimensional speckle-tracking echocardiography in patients with right ventricular myocardial infarction

Right ventricular myocardial infarction (RVMI) damages the systolic and diastolic functions of the RV, so the right atrium interacts with the RV with an acutely altered function. The aim of our study was to compare right atrial function as evaluated by 2D speckle-tracking echocardiography (2DSTE) between patients with inferior wall myocardial infarction (INFMI) and patients affected by both inferior myocardial infarction and right ventricular myocardial infarction (INFMI?+?RVMI). Our study recruited 70 consecutive patients with INFMI (43 patients without RVMI and 27 patients with RVMI). Right atrial function was evaluated by 2DSTE. Early diastolic strain, systolic strain rate, absolute value of early diastolic strain rate, expansion index, and diastolic emptying index of the right atrium were reduced in the patients with INFMI?+?RVMI compared to the patients with INFMI. The area under the curve for early diastolic strain for INFMI diagnosis was 0.682 (p value?=?0.011, 95?% CI 0.550–0.815). Right atrial early diastolic longitudinal strain <27.5?% had 59.3?% sensitivity and 79.1?% specificity for the discrimination of INFMI?+?RVMI from INFMI. Our results demonstrated that right atrial reservoir and conduit functions were impaired in the patients with INFMI?+?RVMI compared with the patients with INFMI.     

Body surface mapping vs 12-lead electrocardiography to detect ST-elevation myocardial infarction

A prospective, multicenter trial was conducted in patients with nontraumatic chest pain in 4 hospitals to determine whether an 80-lead body surface map electrocardiogram system (80-lead BSM ECG) improves detection of ST-segment elevation in acute myocardial infarction (STEMI) compared with a standard 12-lead electrocardiogram (ECG) in an emergency department (ED) setting. A trained ED or cardiology staff member (technician or nurse) recorded a 12-lead ECG and 80-lead BSM ECG from each subject at initial presentation. Serial biomarkers (total creatine kinase [CK], CK-MB, and/or troponin) were obtained according to individual hospital practice. Of the 647 patients evaluated, 589 had available biomarkers results. Eighty-lead BSM ECG improved detection of biomarker-confirmed STEMI compared with the 12-lead ECG for CK-MB–defined STEMI (100% vs 72.7%, P = .031; n = 364) or troponin-defined STEMI (92.9% vs 60.7%, P = .022; n = 225). Specificity for STEMI was high (range, 94.9%-97.1%) with no significant difference between 80-lead BSM ECG and 12-lead ECG. Right ventricular involvement complicating inferior STEMI was detected by 80-lead BSM ECG in 2 (22%) of 9 patients with CK-MB–defined MI and in 2 (22%) of 9 patients with troponin-defined MI. The infarct location missed most commonly on 12-lead ECG but detected by 80-lead BSM ECG was inferoposterior MI. We conclude that BSM using 80-lead BSM ECG is more sensitive for detection of STEMI than 12-lead ECG, while retaining similar specificity.     

A case of de Winter syndrome presenting with chest tightness

de Winter syndrome, also termed anterior ST-segment elevation myocardial infarction (STEMI) equivalent, is estimated to be present in approximately 2% of patients with acute myocardial infarction, but is often under-recognized by clinicians. Therefore, de Winter syndrome is associated with increased morbidity and mortality. We report a 51-year-old man with typical chest tightness and a characteristic electrocardiographic pattern without classic ST-segment elevation, but with acute nearly total occlusion of the left anterior descending coronary artery. Although the patient presented as a non-STEMI case, the definite diagnosis of de Winter syndrome was made on the basis of clinical and electrocardiographic findings. The patient’s symptom of chest tightness was relieved immediately after acute percutaneous coronary intervention and the left ventricular ejection fraction had not deteriorated at 1 month of follow-up.     

急性心肌梗死溶栓再通后心力衰竭的危险因素

目的：探讨急性心肌梗死溶栓再通后住院期间发生心力衰竭的危险因素。方法选取我院住院的急性ST 段抬高型心肌梗死(STEMI)溶栓再通后的患者130例,根据住院期间是否发生心力衰竭,分为心力衰竭组31例和非心力衰竭组99例。比较两组患者一般临床特征、危险因素、血压、白细胞计数(WBC)、肌钙蛋白(cTnI)、生化指标、心肌梗死面积(MIA)、左心室射血分数(LVEF)、B 型脑钠肽(BNP)等相关指标,分析 STEMI 患者溶栓再通后住院期间发生心力衰竭的因素。结果2组间年龄、糖尿病史、发病到血管再通时间、收缩压、前壁心肌梗死及广泛前壁心肌梗死比例、MIA、血糖、cTnI、WBC、γ-谷氨酰转肽酶(GGT)、LVEF、BNP 比较,差异具有统计学意义(P <0.05)。发病到血管再通时间延长(OR =4.402,95% CI =1.565~12.382)、收缩压升高(OR =1.095,95% CI =1.019~1.175)、高血糖(OR =2.132,95% CI =1.127~4.033)、高 cTnI(OR =1.352,95% CI =1.031~1.773)、GGT 升高(OR =1.182,95% CI =1.204~1.365)、高 MIA(OR =1.656,95% CI =1.162~2.360)是 STEMI 溶栓再通患者住院期间发生心力衰竭的危险因素。结论发病到血管再通时间延长、收缩压升高、高血糖、高 cTnI、GGT 升高及高MIA 是 STEMI 溶栓再通患者住院期间发生心力衰竭的危险因素。     

Difficulties in diagnosis of infarction of the right ventricular myocardium

About half of the patients with symptoms of inferior acute myocardial infarction (MI) of the left ventricle (LV) are found to have proximal occlusion of the dominant right coronary artery presented on ECG by ischemia or infarction of the right ventricular wall. Hypotension, high pressure in the jugular veins and, in some cases, shock with clear lung fields--typical clinical picture of right ventricular MI. The diagnosis begins with ECG picture of LV lower wall ischemia (rise of ST wave in leads II, III and aVF) with possible emergence of a pathological wave Q and right ventricular ischemia (rise of ST wave in leads V3R-V6R and its depression in leads V2-V4). Echo-CG and balanced radioventriculography were used for verification of the diagnosis, precise localization of the myocardial lesion. Therapy of patients with right ventricular MI consists in maintenance of adequite preload of the right ventricle, inotropic support and control over atrioventricular conduction.     

Primary Angioplasty in Patient with St-Segment Elevation Myocardial Infarction in the Setting of Intentional Carbon Monoxide Poisoning

Background

ST-segment elevation myocardial infarction (STEMI) due to coronary artery occlusion in the setting of acute carbon monoxide (CO) poisoning is a very rare presentation.

Objective

Our aim was to report on the use of primary angioplasty in a patient with STEMI in the setting of CO poisoning.

Case Report

A 36-year-old man with retrosternal chest pain was admitted after exposure to CO. The initial electrocardiogram (ECG) showed ST depression in I, aVL, and V3−V4 with slight ST elevation in II, III, aVF leads. Toxic carboxyhemoglobin level of 22% and troponin I of 2.19 μg/L were confirmed. After oxygen therapy the chest pain diminished, but after about 15 h it returned. The repeat ECG revealed normalization of previous ST depression with persistent ST elevation in II, III, aVF leads. The troponin I concentration was 5.94 μg/L. An echocardiogram demonstrated an apex hypokinesia involving the adjacent segments of the anterior and lateral wall. On the coronary angiogram, an acute occlusion of the distal left anterior descending coronary artery was confirmed. Primary percutaneous coronary intervention (PCI) of the infarct-related artery was performed. After PCI, the patient was symptom free and had partial ST-segment elevation resolution. The patient was discharged home after 7 days, with persistent ST-T changes and mild hypokinesia of the apex suggesting myocardial injury.

Conclusions

Patients with toxic CO exposure who have symptoms of STEMI should be carefully evaluated with serial ECG, cardiac necrosis marker measurements, and an echocardiogram. When there is evidence of myocardial injury, a wider use of coronary angiography can identify patients who could benefit from PCI.     

Ventricular septal rupture with right ventricular wall dissection after inferior ventricular infarction: A case report and literature review

Right ventricular (RV) wall dissection following ventricular septal rupture related to inferior myocardial infarction (MI) is an extremely rare complication with a high mortality rate. We report the case of a 61-year-old man who was admitted to our hospital because of syncope and intermittent chest pain with a precordial murmur. Transthoracic echocardiography showed a rupture at the basal infero-posterior septum and RV free-wall dissection forming an echolucent cavity that extended beyond the septum and subsequently re-entered into RV chamber. The patient's overall cardiac and renal functions deteriorated and he died 24 days after the diagnosis. We present a literature review of the published cases of complex dissecting tracts through the septum and RV wall in ischemic context.     

Tako-tsubo-like left ventricular dysfunction with ST-segment elevation after central spinal cord injury: a case report

The etiology of a novel cardiac syndrome called "tako-tsubo" cardiomyopathy, otherwise known as "acute onset and reversible left ventricular apical wall motion abnormality (ballooning)," is very similar to that of acute myocardial infarction; however, it may also be associated with emotional or physical stress. We report a case of tako-tsubo-like left ventricular dysfunction with ST-segment elevation after trauma. A 69-year-old man was transferred to our hospital after a fall in which he injured his back. He was diagnosed with a central spinal cord injury and was admitted to our Intensive Care Unit. He complained of a sudden chest pain 12 h after the injury. ST-segment elevation was observed on the electrocardiographic monitor, and subsequent 12-lead electrocardiogram demonstrated ST-segment elevation in leads V(2) through V(5). We considered acute myocardial infarction or cardiac contusion to be the cause of this event; therefore, an emergency coronary angiography was performed. However, the angiography revealed no significant coronary artery stenosis. Furthermore, left ventriculography demonstrated severe hypokinesis of the left ventricular apical region, consistent with tako-tsubo-like left ventricular dysfunction. The patient's cardiac function improved gradually, and he was discharged from our hospital on the 18(th) day after admission. Physicians should recognize the syndrome of tako-tsubo-like left ventricular dysfunction, which may result from traumatic stress or chest injury.