Role of nitric oxide during coronary endothelial dysfunction after myocardial infarction

This study aimed to investigate whether permanent ischaemia influences subacute vasodilatation responses of non-infarcted rat coronary vasculature, and to characterise these coronary changes. Ischaemia led to a significant impairment of the endothelium-dependent vasodilator response, while coronary vasodilatory capacity remained unaltered. In normal coronary circulation, nitric oxide (NO) and prostanoids contributed to vasodilatation, while basal involvement of endothelium-derived hyperpolarising factor was limited. Vasodilatory impairment following myocardial infarction did not originate from alterations in the prostanoid pathway, and only a slightly increased influence of K+ channels was observed. However, NO-mediated vasodilatation was significantly increased after ischaemia, as also confirmed by higher mRNA and protein levels of iNOS and eNOS. Additionally, the amount of superoxide was enhanced following infarction. We conclude that subacute postinfarction remodeling is accompanied by endothelial dysfunction in non-infarcted coronary arteries. Although the NO-mediated response is increased after ischaemia, its final action is restricted due to the presence of superoxide.     

Autonomic impairment after myocardial infarction: Role in cardiac remodelling and mortality

1. Impairmant of baroreflex sensitivity (BRS) has been implicated in the reduction of heart rate variability (HRV) and in the increased risk of death after myocardial infarction (MI). In the present study, we investigated whether the additional impairment in BRS induced by sinoaortic baroreceptor denervation (SAD) in MI rats is associated with changes in the low‐frequency (LF) component of HRV and increased mortality rate. 2. Rats were randomly divided into four groups: control, MI, denervated (SAD) and SAD + MI rats. Left ventricular (LV) function was evaluated by echocardiography. Autonomic components were assessed by power spectral analysis and BRS. 3. Myocardial infarction (90 days) reduced ejection fraction (by ～42%) in both the MI and SAD + MI groups; however, an increase in LV mass and diastolic dysfunction were observed only in the SAD + MI group. Furthermore, BRS, HRV and the LF power of HRV were reduced after MI, with an exacerbated reduction seen in SAD + MI rats. The LF component of blood pressure variability (BPV) was increased in the MI, SAD and SAD + MI groups compared with the control group. Mortality was higher in the MI groups compared with the non‐infarcted groups, with an additional increase in mortality in the SAD + MI group compared with the MI group. Correlations were obtained between BRS and the LF component of HRV and between LV mass and the LF component of BPV. 4. Together, the results indicate that the abolishment of BRS induced by SAD in MI rats further reduces the LF band of HRV, resulting in a worse cardiac remodelling and increased mortality in these rats. These data highlight the importance of this mechanism in the prognosis of patients after an ischaemic event.     

Eplerenone after myocardial infarction?

Each year in the UK, an estimated 50,000 patients develop major left ventricular systolic dysfunction (LVSD) and heart failure following a myocardial infarct.1 Such patients have a particularly poor prognosis. Eplerenone (Inspra - Pfizer) is an aldosterone-receptor antagonist for patients who have LVSD and heart failure following a recent myocardial infarct. Here, we discuss whether such patients should receive this drug.     

临时起搏在抢救急性心肌梗死伴缓慢心律失常中的应用

急性心肌梗死(AMI)常合并严重的心律失常,尤其是急性下壁、广泛前壁梗死易伴严重的窦性心动过缓、窦性停搏和Ⅲ度房室传导阻滞等过缓性心律失常,且为患者早期死亡的原因之一.及时安装心脏临时起搏器进行治疗,可使患者平稳渡过危险期,降低病死率.近年来,我们采用临时心脏起搏抢救其患者16例.现报告如下.     

Work-related outcomes after a myocardial infarction

STUDY OBJECTIVE: To evaluate work-related outcomes of patients at 7 months after a myocardial infarction and to identify patient, disease, and intervention characteristics associated with these outcomes. DESIGN: Cross-sectional survey analysis. SETTING: Large Midwestern academic health system. PATIENTS: Eighty-nine patients with the discharge diagnosis of acute myocardial infarction during a 1-year index period. INTERVENTION: Work performance questionnaire administered by telephone, and medical record review. MEASUREMENTS AND MAIN RESULTS: Seven months after discharge, 232 patients were interviewed by telephone to determine work status before and after myocardial infarction, work-related outcomes (absenteeism and perceived work performance, assessed by the Work Performance Scale [WPS] of the Functional Status Questionnaire), and health-related quality of life. Univariate analyses were used to determine the association between individual characteristics and work-related outcomes. Of the 89 patients who had worked before the index myocardial infarction, 21 (23.6%) did not return to work. Variables associated with the outcome of not returning to work were past myocardial infarction (before the index myocardial infarction), coronary artery bypass graft surgery, heart failure, positive stress test, and low score on the Physical Component Summary (PCS-12) scale of the Short Form-12. Patients who did not return to work also tended to have more comorbidities and take more prescribed drugs than those who returned to work. Median WPS scores were higher for patients who had higher ejection fractions at discharge, had not experienced a myocardial infarction before the index event, underwent a percutaneous revascularization intervention at the time of hospitalization, and had not recently been absent from work. Workers reporting absences had lower PCS-12 scores than their counterparts or reported a rehospitalization before the survey. CONCLUSION: Preexisting cardiac disease and poorer physical functioning were consistently related to worse work-related outcomes. This small study demonstrates the need for a larger, broader study that includes health beliefs, treatment, and other job and patient factors that may influence work-related outcomes.     

Psychological rehabilitation after myocardial infarction.

The value of psychological counselling in rehabilitating patients after myocardial infarction was assessed. A total of 143 men who had recently had a myocardial infarction were randomly allocated to either a group receiving intensive rehabilitation or a control group, their outcome being examined after six months. Patients with neurotic, introverted personalities had a poor outcome in the control group but a satisfactory outcome when rehabilitated. Neurotic personalities responded to help, and rehabilitative measures did not increase neurosis. In addition all patients with a negative attitude towards their illness and future had a poor outcome but those with a positive attitude did well. Selection by simple methods of patients who would benefit from psychological rehabilitation seems desirable.     

心脏电机械活性标测系统检测心肌梗死后存活心肌

目的探讨心脏电机械活性标测系统(NOGATM)检测心肌梗死后存活心肌的可行性及应用价值。方法建立苏中幼猪急性心肌梗死模型,1 个月后分别行99mTc MIBI 18 F FDG双核素(DISA)心肌显像及NOGATM标测,DISA图像及标测三维重建图像采取9分段法进行对比分析。结果正常心肌(14 0±4 5) mV、存活心肌(9 8±3 5) mV、坏死心肌(4 3±2 7) mV之间单极电压值有显著性差异(P<0 05或<0 01)。以12 5 mV作为判断正常心肌界值,敏感性和特异性均为85%;以6 9 mV作为判断坏死心肌界值,敏感性为82%,特异性为75%。结论NOGATM可以用来检测存活心肌,单极电压低于6 9 mV提示心肌坏死。     

Acute myocardial infarction after hydrochloric acid ingestion

We report a case of acute ST segment elevated myocardial infarction associated with hydrochloric acid ingestion. Severe systemic acidosis developed shortly after massive hydrochloric ingestion; it was complicated by the presence of acute myocardial infarction. A new complication of acid ingestion is presented and a possible mechanism is discussed.     

Targeting danger-associated molecular patterns after myocardial infarction

Introduction: Myocardial infarction (MI) provokes an intense inflammatory response that can lead to left ventricular adverse remodeling and heart failure (HF). The prognosis of HF patients is poor and related to a decreased quality of life and considerable health care costs. Hence, targeting the early inflammatory response after MI provides an interesting target to attenuate left ventricular remodeling and prevent HF.

Areas covered: In the current review, we discuss the theory that our immune system does not distinguish between self and non-self, but rather senses danger. So-called danger-associated molecular patterns (DAMPs) serve as ligands for pattern recognition receptors (PRRs), which act as signal transduction molecules to induce a pro-inflammatory state. Many different DAMPs and PRRs have been identified recently. Here, we provide a concise overview of their interactions as well as their role in the inflammatory response after MI.

Expert opinion: Interference with Toll-like receptor (TLR) 2, TLR4 and NLRP3-inflammasome signaling has consistently shown to reduce infarct size and preserve cardiac function post-MI in experimental animal models. Since clinically applicable inhibitors have been developed for these pathways, the path has been cleared to assess whether these promising results can be translated into the human situation.