Inconsistencies in cardiac arrest reporting

Data relating to survival from in-hospital cardiac arrest are used to audit staff performance and to help to determine whether new resuscitation techniques are effective. Individual studies into outcome from cardiac arrest have defined inclusion and exclusion criteria, but no such national criteria have been published to enable constant auditing of cardiac arrests. The aim of this survey was to investigate the consistency with which in-hospital cardiac arrests are recorded throughout the United Kingdom. Such data are, almost universally, collected by Resuscitation Officers (RO). A questionnaire was sent to ROs across the UK asking them to state how they would interpret and categorise hypothetical, but nonetheless typical, clinical situations involving a cardiac arrest team being called. These included an event where the patient had regained consciousness prior to the arrival of the cardiac team and also an event where rigor mortis was already present and the resuscitation promptly abandoned upon the arrival of the cardiac arrest team. The percentage survival to discharge of adult cardiac arrests for each hospital was also requested. This identified whether inclusion or exclusion of certain clinical events may have influenced cardiac arrest survival figures for that hospital. It is clear from this study that in-hospital clinical events when a cardiac arrest team is called are audited with a great deal of inconsistency. Some events, such as a patient who has rigor mortis, are excluded as a false or inappropriate call in some hospitals and included as an unsuccessful resuscitation in others. There is a need for guidance on the inclusion and exclusion criteria for auditing of cardiac arrests so that meaningful data can be obtained from across the UK and useful conclusions drawn. The situation at present will result in data being audited that are of limited use. In the era of evidence-based medicine, it seems vital to obtain accurate cardiac arrest survival figures in order to have any hope of improving them.     

Pre-hospital assessment with ultrasound in emergencies: implementation in the field

BACKGROUND: Point-of-care ultrasound (US) is a proven diagnostic imaging tool in the emergency department (ED). Modern US devices are now more compact, affordable and portable, which has led to increased usage in austere environments. However, studies supporting the use of US in the prehospital setting are limited. The primary outcome of this pilot study was to determine if paramedics could perform cardiac ultrasound in the field and obtain images that were adequate for interpretation. A secondary outcome was whether paramedics could correctly identify cardiac activity or the lack thereof in cardiac arrest patients.METHODS: We performed a prospective educational study using a convenience sample of professional paramedics without ultrasound experience. Eligible paramedics participated in a 3-hour session on point-of-care US. The paramedics then used US during emergency calls and saved the scans for possible cardiac complaints including: chest pain, dyspnea, loss of consciousness, trauma, or cardiac arrest.RESULTS: Four paramedics from two distinct fire stations enrolled a total of 19 unique patients, of whom 17 were deemed adequate for clinical decision making (89%, 95%CI 67%-99%). Paramedics accurately recorded 17 cases of cardiac activity (100%, 95%CI 84%-100%) and 2 cases of cardiac standstill (100%, 95%CI 22%-100%).CONCLUSION: Our pilot study suggests that with minimal training, paramedics can use US to obtain cardiac images that are adequate for interpretation and diagnose cardiac standstill. Further large-scale clinical trials are needed to determine if prehospital US can be used to guide care for patients with cardiac complaints.     

心脏直视手术中心脏复苏困难的处理

目的：为提高心脏直视手术中心脏复苏率。方法：总结２０例心脏直视手术中心脏复苏困难的处理经验。结果：胸内心脏挤压和中等剂量心脏兴奋剂有利于心脏手术中的心脏复苏；心肌出现粗颤即应尽早除颤，不宜片面追求较高的心脏自动复跳率。对复苏困难病例，依其不同情况，在常规复苏方法的基础上，可采用一些特殊复苏措施，包括消除导致复苏困难的原因、长时间心脏挤压和长时间体外循环辅助、采用外科手段等。结论：有多种因素影响心脏直视手术中的心脏复苏，正确分析判断复苏困难的特殊原因，恰当地采用综合性措施（包括外科手段）进行复苏可收到良好效果。     

Stress-dependent cardiac remodeling occurs in the absence of microRNA-21 in mice

MicroRNAs inhibit mRNA translation or promote mRNA degradation by binding complementary sequences in 3' untranslated regions of target mRNAs. MicroRNA-21 (miR-21) is upregulated in response to cardiac stress, and its inhibition by a cholesterol-modified antagomir has been reported to prevent cardiac hypertrophy and fibrosis in rodents in response to pressure overload. In contrast, we have shown here that miR-21-null mice are normal and, in response to a variety of cardiac stresses, display cardiac hypertrophy, fibrosis, upregulation of stress-responsive cardiac genes, and loss of cardiac contractility comparable to wild-type littermates. Similarly, inhibition of miR-21 through intravenous delivery of a locked nucleic acid-modified (LNA-modified) antimiR oligonucleotide also failed to block the remodeling response of the heart to stress. We therefore conclude that miR-21 is not essential for pathological cardiac remodeling.     

Creatinine-kinase-MB determination in non-cardiac trauma: its difference with cardiac infarction and its restricted use in trauma situations.

Cardiac injuries can be life threatening. The possibility of late complications urges the practitioner to search for any evidence of cardiac trauma. But the diagnosis of cardiac injury remains difficult. Electrocardiography and cardiac enzyme determination are most widely used, because they are readily available. Many studies advocate creatine-kinase-MB (CK-MB) isoenzyme levels as a sensitive test for cardiac contusion. Others have discarded CK-MB testing as useless in trauma situations. An elevated CK-MB value in haemodynamically stable patients may confuse the individual practitioner. To better clarify its role we investigated the course of CK/CK-MB release after trauma, with no or only a very small chance of cardiac injury and compared it with patients with severe chest trauma having cardiac complications. A total of 25 trauma patients with only skeletal muscle injury were studied. Blood samples were taken during the first 4 days after trauma. These results were compared with those of a group of 91 consecutive patients with severe chest injury, including 10 with cardiac complications. Initial results in skeletal trauma patients were indicative of cardiac injury (CK > 5% of total CK and at least 20 U/l) in 10 patients. These findings were identical to those found in patients with severe chest injury having cardiac complications. CK/CK-MB tests are frequently positive after trauma without cardiac injury, even when selective criteria are used. The time each isoenzyme is released from muscle tissue after trauma greatly influences the outcome of the test. As this release does not occur at the same moment for each isoenzyme, the test result is very much time-dependent. As a result of these findings CK-MB testing tends to cause more confusion than clarification in trauma situations. We therefore eliminated CK-MB testing from our trauma protocol as a screening investigation for cardiac injury.     

心肌肌钙蛋白在非缺血性心脏病中的诊断应用

心肌肌钙蛋白已经成为诊断急性心肌梗死的一种非常有意义的工具。但是,随着对其诊断能力的重新界定,心肌肌钙蛋白在临床应用中出现了新的问题和不确定性。当心肌肌钙蛋白的升高由非急性心肌缺血的发生而引起时,需要临床医生探寻其他引起心肌肌钙蛋白升高的原因。有许多心肌肌钙蛋白升高的临床情况并非急性冠脉综合征或急性心肌梗死等缺血性心脏病引起,现就此作一综述。     

The role of echocardiography in diagnosing space-occupying lesions of the heart

In contrast to primary cardiac tumors, which are less frequent and mostly benign in nature, the majority of intracardiac tumors are metastatic lesions. Cardiac ultrasound has evolved enormously since its emergence in the 1950s and is presently the modality of choice for imaging space-occupying lesions of the heart; it provides high quality, real-time images that are extremely valuable in the evaluation of cardiac masses. Although transthoracic echocardiography is an excellent initial diagnostic technique to evaluate and diagnose cardiac masses, transesophageal echocardiography provides superior image resolution and better visualization of cardiac masses in patients with suboptimal transthoracic echocardiography studies. Computed tomography and magnetic resonance imaging are additional tools used for cardiac imaging and may provide useful information in addition to that obtained by echocardiography, especially when the images obtained by the latter are suboptimal.     

The utility of cardiac sonography and capnography in predicting outcome in cardiac arrest

Emergency physicians and intensivists are increasingly utilizing capnography and bedside echocardiography during medical resuscitations. These techniques have shown promise in predicting outcomes in cardiac arrest, and no cases of return of spontaneous circulation in the setting of sonographic cardiac standstill and low end-tidal carbon dioxide have been reported. This case report illustrates an example of such an occurrence. Our aims are to report a case of return of spontaneous circulation in a patient with sonographic cardiac standstill, electrocardiographic pulseless electrical activity, and low end-tidal carbon dioxide tensions and to place the case in the context of previous literature on this topic. Case report and brief review of the literature. In 254 cases reported, no patient has survived in the setting of sonographic cardiac standstill and low end-tidal carbon dioxide tension, making the reported case unique. This case should serve to illustrate the utility and limitations of combined cardiac sonography and end-tidal carbon dioxide measurement in determining prognosis during cardiac arrest.     

Weighing in on molecular anchors: the role of ankyrin polypeptides in human arrhythmia

Loss-of-function gene variants which affect the biophysical properties of ion channel proteins have long been associated with the destabilization of cardiac electrical activity, leading to human arrhythmia and sudden cardiac death. However, recent studies have also demonstrated the importance of ion channel/transporter-anchoring molecules for normal cardiac function. Ankyrins are a family of membrane adaptor proteins whose role in metazoan physiology has been elucidated over the last quarter of a century, but with great strides taken in the last half decade with regard to cardiac cell physiology. The association of dysfunction in ankyrin-based cellular pathways with abnormal human cardiac function represents a surprising turn in the genetics of arrhythmias and sudden cardiac death, demonstrating an exciting new player in the field of 'channelopathies'.     

Magnesium in cardiopulmonary resuscitation: critical review

Although many different drugs and interventions have been studied in cardiac arrest to improve survival rates and neurological outcome, the results are still very poor. Magnesium (Mg) has important electrophysiological effects and normal concentrations are required to maintain regular cardiac conduction, rhythm and vascular tone, but its role in improving survival rates and neurological outcome in victims of cardiac arrest is not completely understood. We conducted a systematic review to identify evidence regarding the role of Mg in cardiac arrest. Specifically, we looked for data to answer if survival rates and neurological outcome are related to the administration of Mg either during CPR or following return of spontaneous circulation. We found that there are very few data available about the role of Mg in the treatment of cardiac arrest. Although two non-randomised and one animal study reported promising results, the lack of high quality studies makes it impossible to recommend for or against the administration of Mg during or early after resuscitation to improve outcome.     

利钠肽的研究进展

利钠肽家族作为内分泌激素，能够通过调节心脏和。肾脏的功能达到维持机体的内稳态。对利钠肽的最新研究表明，心力衰竭等心脏病患者的利钠肽水平升高，升高的利钠肽提示心血管事件的高危险性，监测利钠肽能够帮助诊断和判断预后。利钠肽能够抑制心肌的过度增殖和纤维化，具有改善心肌梗死和心衰时的心肌重构作用。脑钠肽是一种最重要的利钠肽，它可以作为心衰和其他心血管疾病的重要生物标记物，能够帮助我们了解肺动脉高压和粥样硬化性血管病等心血管疾病的进展。另外，合成的多种利钠肽如nesiritide已经被试验用来治疗急性充血性心衰。针对多种重组利钠肽的多个临床研究还在实验阶段，主要的方向包括它们在心脏手术中对心脏、肾脏的保护作用和抑制心肌重构的作用。     

Role of calcium blockers in protecting the myocardium in cardiac surgery

Calcium plays an essential role in ischemic events observed during cardiac surgery. Many experiments have studied the effects of calcium channel blockers on intracellular calcium overload during the periods of cardiac ischemia and reperfusion. Calcium channel blockers are no longer used before and during cardiac surgery because hypothermia inhibits their pharmacological action. However, during the post-operative period, calcium channel blockers are the drugs of choice to control coronary spasm, and arterial hypertension which is secondary to peripheral vasoconstriction.     

Psychology in coronary care

Psychological stress has been implicated in the onset and progression of coronary heart disease (CHD). Recent research has highlighted the importance of depression and anxiety as independent risk factors for mortality in cardiac patients. Accordingly, it is critical that clinically significant levels of distress are identified, both in-hospital and after discharge, to target patients who require specific psychological intervention, in addition to conventional cardiac rehabilitation. Ameliorating distress has been shown to improve adherence to treatment advice, such as modifying cardiac risk factors, compliance with medication regimens, and attendance at exercise programmes, which in turn should reduce cardiac morbidity and mortality. The emphasis within cardiac rehabilitation should be on tailoring provision to meet individual patients' needs.     

Weighing in on molecular anchors: the role of ankyrin polypeptides in human arrhythmia

Loss-of-function gene variants which affect the biophysical properties of ion channel proteins have long been associated with the destabilization of cardiac electrical activity, leading to human arrhythmia and sudden cardiac death. However, recent studies have also demonstrated the importance of ion channel/transporter-anchoring molecules for normal cardiac function. Ankyrins are a family of membrane adaptor proteins whose role in metazoan physiology has been elucidated over the last quarter of a century, but with great strides taken in the last half decade with regard to cardiac cell physiology. The association of dysfunction in ankyrin-based cellular pathways with abnormal human cardiac function represents a surprising turn in the genetics of arrhythmias and sudden cardiac death, demonstrating an exciting new player in the field of ‘channelopathies’.     

Noncardiac Surgery in Cardiac Patients

Complications of noncardiac surgery in cardiac patients are better managed and often prevented by monitoring certain vital functions. Some of the complications discussed here are electrolyte imbalance, hypovolemia, hypervolemia, hypotension, respiratory depression, fever, and thrombophlebitis and pulmonary embolism. The complications causing surgical mortality are the same for cardiac and noncardiac patients, but are more prevalent and more poorly tolerated in the cardiac patient.     

Hemodynamic effects of phenoxybenzamine in anesthetized dogs

Our studies demonstrated that phenoxybenzamine, 10 mg/kg, administered intravenously to intact anesthetized dogs, produced an immediate and significant increase of heart rate and cardiac output. In heart-lung preparations, phenoxybenzamine had no effect or a negative cardiac inotropic effect, hence these actions were not related to direct cardiac action or to release of myocardial norepinephrine stores. Serial estimations of arterial blood catecholamines after phenoxybenzamine showed an increase of epinephrine and norepinephrine; the peak values of these catecholamines did not correlate well with the maximum cardiac output responses. Ganglionic blockade largely eliminated the early cardiac effects of phenoxybenzamine, hence its action did not appear to be upon peripheral terminals of postganglionic sympathetic or parasympathetic nerves. Phenoxybenzamine was found to have antivagal actions which might account for some of the delayed cardiac acceleration. When beta adrenergic receptor blockade was induced by sotalol, the cardiac effects of phenoxybenzamine were largely eliminated. Baroreceptor denervation prevented the increase of cardiac output after phenoxybenzamine. These observations are consistent with the concept that the increase of cardiac rate and output produced by phenoxybenzamine is principally mediated by baroreceptor reflexes acting through sympathetic cardiac nerves or circulating catecholamines.     

Imaging as an End Point in Ischemia Trials

Imaging of cardiac function and anatomy has advanced at an exponential rate over the past two decades. Our ability to quantitatively assess the degree of myocardial ischemia and accurately define the vascular anatomy using noninvasive techniques is greater than ever before. Current advances is cardiac imaging are allowing us to more safely assess patients for myocardial ischemia and better understand the prognostic implications of our findings. This review summarizes the current state of knowledge in cardiac imaging for the assessment of cardiac ischemia with a focus on the use of cardiac MRI.     

Role of thrombolytic agents in cardiac arrest

The prognosis of patients having a cardiac arrest is generally poor, with a few exceptions. Interventions that aim to improve outcome in cardiac arrest have proved to be disappointing. In particular, no drug has been reliably proved to increase survival to discharge after cardiac arrest. Given that coronary thrombosis in situ and pulmonary thromboembolism are implicated in a large proportion of patients with cardiac arrest, the use of thrombolytic agents has been suggested. Case reports and animal studies have shown favourable results, and have proposed plausible mechanisms to explain them. This is a review of the current literature focusing on the use of thrombolysis during cardiac arrest. A comprehensive literature search was carried out on Medline from 1966 to January 2006, Embase from 1988 to January 2006 and the Cochrane Library, using the Ovid interface. Six articles were selected for review. Although some results are encouraging, all the studies currently available are limited by size and flaws in design.     

Treatment of Hyperkalemia in a Patient with Unrecognized Digitalis Toxicity

Cardiac glycoside toxicity is frequently associated with hyperkalemia and dysrhythmias in patients with renal insufficiency. Two common therapeutic options for these complications (calcium and transvenous cardiac pacing) are considered contraindicated in the setting of cardiac glycoside toxicity. We present the case of a patient presenting with a pronounced bradydysrhythmia and hyperkalemia who was treated with intravenous calcium and transvenous cardiac pacing and later found to have digitalis toxicity and acute renal failure. There were no adverse events associated with the therapies. The patient received digoxin-specific Fab fragments and hemodialysis as definitive therapeutic modalities. The case and the relevant literature evaluating the interaction of calcium salts and cardiac pacing in the setting of cardiac glycoside toxicity are discussed.     

Clinical utility of Doppler ultrasound in cardiac diseases

During the past decade Doppler echocardiography has evolved to an extent that it has become a major noninvasive tool for cardiac evaluation in both acquired and congenital heart disease. This article describes current applications of Doppler techniques in the evaluation of cardiac anatomy and hemodynamics. The principles and methods employed in the use of Doppler echocardiography are described and illustrated for assessment and quantitation of flow velocities, pressure gradients, valve areas, valve regurgitation, stroke volume, cardiac output, cardiac shunts, and diastolic filling indices. The increasing accuracy of these applications has led to a substantial reduction in the need for invasive diagnostic methods, such as cardiac catheterization, especially in patients where frequent follow-up evaluations are indicated.